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CompletedNCT03617185Updated Sep 17, 2026Results posted

Effect of Exercise and Surgical Weight Loss on Polyneuropathy

An interventional study of High Intensity Interval Training (HIIT) and Routine Exercise in Polyneuropathies, Obesity and Bariatric Surgery Candidate, sponsored by University of Michigan. Completed at 1 site in United States. Open to participants aged 40 Years and older. Per ClinicalTrials.gov, last updated 2026-09-17.

Sponsored by University of Michigan · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
140
Allocation
Randomized
Ages
40 Years and older
Sex
All
01

Study summary

The purpose of this research study is to evaluate how exercise and surgical weight loss affect how likely an individual is to develop peripheral neuropathy and other neurologic complications.

Read the detailed description

The length of this study, including screening is approximately 24 months. Patients at Bariatric Surgery Clinics will be recruited for this study. Both patients that decide to undergo bariatric surgery, and those that do not undergo surgery will be enrolled. Patients will be randomized to either a high intensity interval training (HIIT) or standard exercise regimen after eligibility is confirmed and the baseline visit is complete. All patients will complete follow-up appointments at 3 month, 12 months and 24 months. Patients that are randomized to the HIIT program will compete 2 supervised and 1 unsupervised training sessions a week for 24 months.

02

Conditions studied

  • Polyneuropathies
  • Obesity
  • Bariatric Surgery Candidate

Keywords

  • Metabolic syndrome
  • Exercise
03

In context

Polyneuropathies

133 studies on the registry are indexed under Polyneuropathies; 33 are open to participants now.

This study's enrollment of 140 is above the median of 63 across 70 interventional studies indexed under Polyneuropathies.

Browse Polyneuropathies studies →

Lead sponsor

University of Michigan is the lead sponsor of 1,506 studies on the registry; 192 are open to participants now.

Of its 169 completed or terminated interventional studies of FDA-regulated products, 133 (79%) have results posted.

Browse University of Michigan studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
40 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Attending a bariatric surgery clinic
  • > 35 with one comorbid condition present or BMI > 40 without comorbid conditions present
  • Willing and capable to sign the Institutional Review Board (IRB) approved consent form and cooperate with the medical procedures for the study duration
  • Willing to accept random treatment assignment to HIIT or routine exercise counseling

Exclusion criteria

Exclusion Criteria:

  • History of distal symmetric polyneuropathy (DSP) from causes other than diabetes and/or the metabolic syndrome as determined through medical history, family history, history of medications, occupational history, history of exposure to toxins, physical and neurological examinations;
  • Use of warfarin, heparin, or other anticoagulants, which would increase the risk of complications from skin
  • to HIIT participation including a failed exercise stress test
  • Participation in an experimental medication trial within 3 months of starting the study
  • Undergoing therapy for malignant disease other than basal-cell or squamous-cell skin cancer
  • Medical or psychiatric reason for not being a surgical candidate
  • Requiring a walking assist device;
  • Currently smoking
Terms in these criteria, in plain language(3)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
140 participants (actual)

Study arms

  • Active comparator
    Bariatric Surgery/HIIT

    Patients who have undergone bariatric surgery will be randomized to this arm and will follow a high intensity interval training (HIIT) protocol for 24 months. Patients will complete 2 supervised HIIT sessions and 1 unsupervised HIIT session a week.

    Other: High Intensity Interval Training (HIIT) · Procedure: Bariatric surgery

  • Active comparator
    Bariatric Surgery/Routine Exercise

    Patients who have undergone bariatric surgery will be randomized to this arm and will follow a standard routine exercise regimen for 24 months.

    Other: Routine Exercise · Procedure: Bariatric surgery

  • Active comparator
    No Bariatric Surgery/HIIT

    Patients who have not undergone bariatric surgery will be randomized to this arm and will follow a high intensity interval training (HIIT) protocol for 24 months. Patients will complete 2 supervised HIIT sessions and 1 unsupervised HIIT session a week.

    Other: High Intensity Interval Training (HIIT)

  • Active comparator
    No Bariatric Surgery/Routine Exercise

    Patients who have not undergone bariatric surgery will be randomized to this arm and will follow a standard routine exercise regimen for 24 months.

    Other: Routine Exercise

Interventions

  • OtherHigh Intensity Interval Training (HIIT)

    Patients will complete a HIIT training protocol of a total of 10 x 1 min intervals at 90% heart rate (HR) max. They will continue this training protocol, 3 sessions a week (2 supervised and 1 unsupervised), for 24 months.

  • OtherRoutine Exercise

    Patients will receive counseling regarding exercise as a routine part of their participation in the bariatric surgery clinic. Specifically, they are counseled to participate in 60 min of aerobic exercise daily in addition to 2-3 non-consecutive days of strength training workouts every wk. Patients are encouraged to contact the bariatric conditioning program, obtain a gym membership, purchase exercise equipment, join a walking group, and/or sign up for fitness classes (employer or city parks and recreation).

  • ProcedureBariatric surgery

    Patients will undergo bariatric surgery as part of their routine care

06

What researchers measure

Primary outcomes

  1. Intraepidermal Nerve Fiber Density (IENFD) at the Proximal Thigh

    Intraepidermal Nerve Fiber Density (IENFD) as assessed by 3mm skin biopsies at the proximal thigh.

    Time frame: Baseline, 3 months, 12 months and 24 months

Secondary outcomes

  1. Intraepidermal Nerve Fiber Density (IENFD) at Distal Leg.

    Intraepidermal Nerve Fiber Density (IENFD) as assessed by 3mm skin biopsies at the distal leg.

    Time frame: Baseline, 3 months, 12 months and 24 months

  2. Corneal Confocal Microscopy (CCM) - Fiber Density

    Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Fiber Density are quantified by fibers/mm2, a higher number represents a higher density of fibers. Lower numbers indicate worse neuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  3. Corneal Confocal Microscopy (CCM) - Branch Density

    Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Branch Density are quantified by branches/mm2, a higher number represents a higher density of branches. Lower numbers indicate worse neuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  4. Corneal Confocal Microscopy (CCM) - Fiber Length

    Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Fiber Length are quantified by mm/mm2, a higher number represents a higher total length of fibers. Lower numbers indicate worse neuropathy .

    Time frame: Baseline, 3 month, 12 months and 24 months

  5. Corneal Confocal Microscopy (CCM) - Tortuosity Coefficient

    Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Tortuosity Coefficient represents the total tortuosity (twisting/bending of nerves). As a coefficient the value is unitless, a higher value represents greater tortuosity. Lower numbers indicate worse neuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  6. 24-2 Frequency Doubling Technology (FDT) - Mean Deviation

    24-2 FDT was used to evaluate retinopathy using visual field deficits. Mean Deviation is presented below. Mean deviation is the average difference from normal expected value in the patients' particular age group. Lower values indicate more visual deficit. Higher values indicate fewer visual deficit.

    Time frame: Baseline, 3 month, 12 months and 24 months

  7. 24-2 Frequency Doubling Technology (FDT) - Foveal Sensitivity dB

    24-2 FDT was used to evaluate retinopathy using visual field deficits. Foveal sensitivity is presented below. Foveal sensitivity is the measurement of the fovea's light detection ability. Lower values suggest visual field deficits.

    Time frame: Baseline, 3 month, 12 months and 24 months

  8. 24-2 Frequency Doubling Technology (FDT) - Pattern SD

    24-2 FDT was used to evaluate retinopathy using visual field deficits. Pattern SD (PSD) is presented below. PSD provides information about localized loss. A higher PSD indicates a non-uniform sensitivity loss and visual field deficit.

    Time frame: Baseline, 3 month, 12 months and 24 months

  9. Retinal Fundus Photography

    As assessed by fundus photographs, participants were identified as either having retinopathy or not having retinopathy. Data is shown as number of people with retinopathy at a particular study visit.

    Time frame: Baseline, 3 month, 12 months and 24 months

  10. Nerve Conduction Study (NCS) - Latency

    Latency measures the time in millisecond between stimulation and the recording electrode. Was performed on sural, peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \>6.5 - Abnormal * Sural: 0 - No response, \>4.5 - Abnormal * Tibial: 0 - No response, \>6.1 - Abnormal

    Time frame: Baseline and 24 months

  11. Nerve Conduction Study (NCS) - Motor Amplitude

    Amplitude measures the height of electrical signal (waveform) in millivolts produced by the stimulated motor nerve. Was performed on peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \< 1.1 - Abnormal * Tibial: 0 - No response, \<1.1 - Abnormal

    Time frame: Baseline and 24 months

  12. Nerve Conduction Study (NCS) - Sensory Amplitude

    Amplitude measures the height of electrical signal (waveform) in microvolts produced by the stimulated sensory nerve. Was performed on sural nerve. No response and abnormal values indicate neuropathy. \* Sural: 0 - No response, \<4 - Abnormal

    Time frame: Baseline and 24 months

  13. Nerve Conduction Study (NCS) - CV

    Conduction velocity (V) measures the speed (m/s) at which the electrical impulse travels along the nerve. Was performed on peroneal nerves. No response and abnormal values indicate neuropathy. Abnormal values are \<36 or 39, depending on whether certain criteria applied to the participant. Data was not analyzed separately.

    Time frame: Baseline and 24 months

  14. Nerve Conduction Study (NCS) - F Wave Index

    F wave index measures the time in millisecond between stimulation at a distal (near the muscle) point and for the stimulus to travel to the spinal cord and back, allowing to assess the entire length of the nerve. Was performed on peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \>55 - Abnormal * Tibial: 0 - No response, \>55 - Abnormal

    Time frame: Baseline and 24 months

  15. Cardiac Autonomic Neuropathy Testing-Deep Breathing/Exhalation to Inhalation (E:I) Ratio

    Deep breathing/exhalation to inhalation (E:I) ratio were evaluated using PS monitor software. Values \< 1 are abnormal, indicative of cardiovascular autonomic neuropathy

    Time frame: Baseline and 24 months

  16. Cardiac Autonomic Neuropathy Testing (30:15 Ratio)

    Postural change-30:15 ratio was evaluated using PS monitor software. Values \< 1 are abnormal, indicative of cardiovascular autonomic neuropathy

    Time frame: Baseline and 24 months

  17. Cardiac Autonomic Neuropathy Testing (Valsalva Ratio)

    Valsalva ratio was evaluated using PS monitor software. Values \<= 1.10 are abnormal, indicative of cardiovascular autonomic neuropathy

    Time frame: Baseline and 24 months

  18. Participants With Probable Polyneuropathy as Defined by the Toronto Definition of Probable Neuropathy

    Toronto definition of probable neuropathy is having at least 2 out of 3 of the following: abnormal sensory examination, reflexes, and patient-reported symptoms. Data is reported as number of participants who, under the Toronto definition, were identified as having probable polyneuropathy.

    Time frame: 24 months

  19. Michigan Neuropathy Screening Instrument (MNSI)

    MNSI questionnaire is scored from 0-15, score \> 4 indicate neuropathy, higher scores indicate worse neuropathy. A score of 1 point is given for answers of "yes" for questions 1-6, 8-12, 14, and 15 and "no" for questions 7 and 13.

    Time frame: Baseline, 3 month, 12 months and 24 months

  20. Michigan Neuropathy Screening Instrument (MNSI) - Exam

    MNSI exam is scored from 0-8, score \>= 2.5 indicate neuropathy. Higher scores indicate worse neuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  21. Michigan Neuropathy Screening Instrument (MNSI) - Index

    The Michigan Neuropathy Screening Instrument (MNSI) index is a weighted composite score computed using the sum of the b-coefficients for all items within the MNSI questionnaire (15 questions) and MNSI exam (4 physical/visual exam). Range: -0.93, 7.39 Values \> 2.5407 are indicative of clinical neuropathy

    Time frame: Baseline, 3 month, 12 months and 24 months

  22. Utah Early Neuropathy Score (UENS)

    UENS is a composite score with five sections measuring multiple clinical measures of nerve injury. Sections are scored separately for each side (Right vs Left), and the total score is the sum across everything. Range: 0-42, higher score represents more severe polyneuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  23. Modified Toronto Neuropathy Score (mTNS)

    mTNS is a scale of 0-33 that measures neuropathy symptoms and exam findings. Higher scores indicate more severe polyneuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  24. Survey of Autonomic Symptoms (SAS)

    SAS evaluates the presence and magnitude of autonomic symptoms. Total impact score ranges from 0-60 (or up to 55 for participants to whom certain criteria did not apply). Higher score indicates worse autonomic neuropathy

    Time frame: Baseline, 3 month, 12 months and 24 months

  25. Diabetic Neuropathy Score (DNS)

    DNS is a questionnaire of neuropathy symptoms. Score ranges 0-4, \>/=1 indicates polyneuropathy. 0 indicates no polyneuropathy.

    Time frame: Baseline, 3 month, 12 months and 24 months

  26. Short Form McGill Pain Questionnaire

    Sum of the sensory score (0-30) and affective score (0-15) for a total score of 0-45. A higher score represents greater pain present.

    Time frame: Baseline, 3 months, 12 months, 24 months

  27. Numerical Rating Scale for Pain

    Participant reported pain scale with range 0-10, higher score indicates more pain.

    Time frame: Baseline, 3 months, 12 months, 24 months

  28. Neuropathy Quality of Life (NeuroQOL)

    Neuropathy Quality of Life (NeuroQOL) evaluates symptoms and function in regard to quality of life over the past four weeks. Range 1-15, higher score indicates neuropathy having a greater impact on quality of life.

    Time frame: Baseline, 3 months, 12 months, and 24 months

  29. 8 Foot Get Up and Go Test

    This test measures in seconds how long it takes the participant to stand up from a seated position, walk around a cone places 8 feet away, and return to the chair and sit down. Less time indicates better speed, agility, and balance when moving.

    Time frame: Baseline, 3 months, 12 months, and 24 months

  30. Berg Balance Scale

    Berg Balance Scale measures participants' ability to balance and avoid falls. Scores range from 0-56, higher score indicates less likely to fall.

    Time frame: Baseline, 3 months, 12 months, and 24 months

  31. Modified Falls Efficacy Scale - Fall Evaluation

    Patient response indicating if they have fallen in the last year. Data is shown as number of people who have fallen in the last year.

    Time frame: Baseline, 3 months, 12 months, and 24 months

  32. Neurothesiometer

    Neurothesiometer is placed on the bottom of the great toe, and slowly increased until participant reports they can feel the vibration. The greater the microns, the less feeling the participant has, suggestive of worse sensory function. Value \> 25 Microns is indicative of neuropathy. There is no known maximum range. Lower values indicate better sensory function.

    Time frame: Baseline, 3 months, 12 months, and 24 months

  33. NIH Toolbox Cognitive Battery

    NIH Toolbox Cognition Fluid (Range: 0-100) - Composite score derived as an average across five cognitive domains. It's a fully adjusted T-score comparing the participant to a nationally representative sample, stratified by age and other demographics. Individual domain scores are fully adjusted T score with range 0-100 and measures the following- * Inhibitory Control and Attention - executive function, attention . * Dimensional Change Card Sort - executive function * Picture Sequence Memory - episodic memory * List Sorting Working Memory - working memory * Pattern Comparison - processing speed A T-score of 50 represents the population mean. A score of 60 indicates that the participant is 1 SD above the national average for individuals with similar demographic characteristics Higher scores reflect better cognitive functionality. No set clinical threshold, scores above mean indicate above average cognition for a given age group.

    Time frame: Baseline and at 24 months

  34. Rey Auditory Verbal Learning Test

    Used to evaluate verbal learning and memory using a list of 15 unrelated words presented to the participant over repeat trial. Includes 3 independent scales: * Auditory Learning (Total recall) - Measures memory and learning ability. Raw score range (0- 75) * Delayed Recall - Measures long term memory retention. Raw score range (0-15) * Recognition - Measures ability to recognize previously learned information. Raw score range (0-15). * Raw scores were converted to age-standardized Z-scores using 10-year age bands (e.g., 20-29, 30-39, 40-49, etc.), with a mean of 0 and standard deviation of 1. * A Z-score of 0 represents the population mean * For each scale, scores above 0 are better. Standard deviations above the mean indicates a better learning and memory ability for a given age group. No set clinical threshold, scores above mean indicate above average cognition for a given age group.

    Time frame: Baseline and at 24 months

07

Results

Posted Oct 29, 2025

Participant flow

Participants were recruited from Bariatric Surgery clinics in Ann Arbor and Detroit.

Baseline
Participant flow — Baseline
MilestoneBariatric Surgery/HIITNo Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/Routine Exercise
Started35353535
Completed35323232
Not completed0333
Withdrew: Lost to follow-up0211
Withdrew: Withdrawal by subject0101
Withdrew: Driving distance/travel0020
Withdrew: Family obligations0001
3 Months
Participant flow — 3 Months
MilestoneBariatric Surgery/HIITNo Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/Routine Exercise
Started35323232
Completed29283229
Not completed6403
Withdrew: Lost to follow-up4102
Withdrew: Withdrawal by subject1300
Withdrew: Driving distance/travel1000
Withdrew: Family obligations0001
12 Months
Participant flow — 12 Months
MilestoneBariatric Surgery/HIITNo Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/Routine Exercise
Started29283229
Completed26272828
Not completed3141
Withdrew: Lost to follow-up3130
Withdrew: Withdrawal by subject0001
Withdrew: Driving distance/travel0010
24 Months
Participant flow — 24 Months
MilestoneBariatric Surgery/HIITNo Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/Routine Exercise
Started26272828
Completed26272828
Not completed0000

Outcome measures

PrimaryIntraepidermal Nerve Fiber Density (IENFD) at the Proximal Thigh

Intraepidermal Nerve Fiber Density (IENFD) as assessed by 3mm skin biopsies at the proximal thigh.

Time frame:
Baseline, 3 months, 12 months and 24 months
Reported as:
Mean · fibers/mm
Intraepidermal Nerve Fiber Density (IENFD) at the Proximal Thigh
fibers/mmBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline11.9 ± 3.912.7 ± 4.49.8 ± 4.911 ± 4.6
3 Months12.6 ± 3.914.3 ± 59.9 ± 4.210.6 ± 6
12 Months11.5 ± 6.114.2 ± 6.29.2 ± 4.28.5 ± 4.4
24 Months11.9 ± 6.013.5 ± 6.210.3 ± 4.39.3 ± 3.8
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.15 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -1.98 · 95% CI -4.63 to 0.74
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.08 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -2.33 · 95% CI -4.98 to 0.31
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.15 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -1.84 · 95% CI -4.43 to 0.74
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.67 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.07 · 95% CI -0.02 to 0.16
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.77 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.09 · 95% CI 0.002 to 0.19
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.69 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.07 · 95% CI -0.02 to 0.16
SecondaryIntraepidermal Nerve Fiber Density (IENFD) at Distal Leg.

Intraepidermal Nerve Fiber Density (IENFD) as assessed by 3mm skin biopsies at the distal leg.

Time frame:
Baseline, 3 months, 12 months and 24 months
Reported as:
Mean · fibers/mm
Intraepidermal Nerve Fiber Density (IENFD) at Distal Leg.
fibers/mmBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline6.3 ± 46.8 ± 4.37.3 ± 4.15.7 ± 3.8
3 Months7.3 ± 4.16.2 ± 4.16.3 ± 3.65.5 ± 3.8
12 Months7.7 ± 5.28.7 ± 5.46.4 ± 3.66.4 ± 5.5
24 Months6.9 ± 4.57.4 ± 4.46.4 ± 3.85.8 ± 4.1
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.27 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.98 · 95% CI -2.77 to 0.79
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.18 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -1.09 · 95% CI -2.71 to 0.53
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.21 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 1.32 · 95% CI -0.82 to 3.48
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.66 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.02 · 95% CI -0.05 to 0.09
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.25 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.05 · 95% CI -0.02 to 0.11
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.09 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.06 · 95% CI -0.13 to 0.01
SecondaryCorneal Confocal Microscopy (CCM) - Fiber Density

Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Fiber Density are quantified by fibers/mm2, a higher number represents a higher density of fibers. Lower numbers indicate worse neuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · fibers/mm^2
Corneal Confocal Microscopy (CCM) - Fiber Density
fibers/mm^2Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Corneal Nerve Fiber Density (fibers/mm2)22.1 ± 6.819.5 ± 5.719.5 ± 6.222.4 ± 5.4
3 Months-Corneal Nerve Fiber Density (fibers/mm2)20 ± 6.519.9 ± 4.919.3 ± 6.519.8 ± 6.3
12 Months-Corneal Nerve Fiber Density (fibers/mm2)19.8 ± 9.420.7 ± 5.217.2 ± 6.318.8 ± 6.8
24 Months-Corneal Nerve Fiber Density (fibers/mm2)20.5 ± 5.120.2 ± 3.919 ± 5.518.8 ± 5.7
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.97 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.06 · 95% CI -3.72 to 3.85
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.03 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -3.82 · 95% CI -7.32 to -0.31
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.38 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -1.56 · 95% CI -5.18 to 2.05
SecondaryCorneal Confocal Microscopy (CCM) - Branch Density

Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Branch Density are quantified by branches/mm2, a higher number represents a higher density of branches. Lower numbers indicate worse neuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · branches/mm^2
Corneal Confocal Microscopy (CCM) - Branch Density
branches/mm^2Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Corneal Nerve Branch Density (branches/mm2)56.4 ± 30.757.1 ± 24.653.6 ± 31.954.7 ± 25.3
3 Months-Corneal Nerve Branch Density (branches/mm2)62.2 ± 3272.6 ± 3462 ± 31.363.9 ± 37.2
12 Months-Corneal Nerve Branch Density (branches/mm2)126.6 ± 68.6137.4 ± 55.101.2 ± 57.9116.8 ± 79
24 Months-Corneal Nerve Branch Density (branches/mm2)124.7 ± 54.3129.8 ± 39.7116.6 ± 49.1127.1 ± 55.9
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.62 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.95 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.59 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryCorneal Confocal Microscopy (CCM) - Fiber Length

Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Corneal Nerve Fiber Length are quantified by mm/mm2, a higher number represents a higher total length of fibers. Lower numbers indicate worse neuropathy .

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · mm/mm2
Corneal Confocal Microscopy (CCM) - Fiber Length
mm/mm2Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Corneal Nerve Fiber Length (mm/mm2)18.6 ± 6.118.9 ± 5.317.9 ± 6.119.3 ± 4.9
3 Months-Corneal Nerve Fiber Length (mm/mm2)19 ± 5.920.6 ± 5.319.3 ± 5.519.3 ± 6.1
12 Months-Corneal Nerve Fiber Length (mm/mm2)25.7 ± 7.528 ± 6.723 ± 8.124.7 ± 8.7
24 Months-Corneal Nerve Fiber Length (mm/mm2)25.2 ± 6.825.3 ± 4.824 ± 6.925.2 ± 7.4
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.89 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.3 · 95% CI -4.26 to 4.86
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.83 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.43 · 95% CI -4.64 to 3.76
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.82 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.51 · 95% CI -4.27 to 5.3
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.51 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.05 · 95% CI -0.11 to 0.21
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.60 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.04 · 95% CI -0.11 to 0.19
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.99 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Mean difference (net): 0.002 · 95% CI -0.17 to 0.17
SecondaryCorneal Confocal Microscopy (CCM) - Tortuosity Coefficient

Non-invasive imaging technique of the corneal nerves to quantify nerve density and morphology. Tortuosity Coefficient represents the total tortuosity (twisting/bending of nerves). As a coefficient the value is unitless, a higher value represents greater tortuosity. Lower numbers indicate worse neuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · Coefficient
Corneal Confocal Microscopy (CCM) - Tortuosity Coefficient
CoefficientBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Corneal Tortuosity (coefficient value)19.4 ± 5.619 ± 6.318.6 ± 6.719.2 ± 4.9
3 Months-Corneal Tortuosity (coefficient value)17.8 ± 4.319.9 ± 5.617.7 ± 4.618.5 ± 4.9
12 Months-Corneal Tortuosity (coefficient value)20.8 ± 7.220.6 ± 5.620.1 ± 7.321.4 ± 5.8
24 Months-Corneal Tortuosity (coefficient value)20 ± 10.122 ± 7.821 ± 4.920.1 ± 5.6
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.82 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.21 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.33 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
Secondary24-2 Frequency Doubling Technology (FDT) - Mean Deviation

24-2 FDT was used to evaluate retinopathy using visual field deficits. Mean Deviation is presented below. Mean deviation is the average difference from normal expected value in the patients' particular age group. Lower values indicate more visual deficit. Higher values indicate fewer visual deficit.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · dB
24-2 Frequency Doubling Technology (FDT) - Mean Deviation
dBBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Mean Deviation-1.6 ± 4.2-1.6 ± 2.7-2 ± 4.1-2.5 ± 4
3 Months-Mean Deviation-1 ± 4.1-1.5 ± 2.7-1.7 ± 4-2.8 ± 4.6
12 Months-Mean Deviation-0.9 ± 3.2-1.3 ± 3.1-2.4 ± 3.8-1.5 ± 4.3
24 Months-Mean Deviation-1.1 ± 3.8-0.7 ± 2.7-2.3 ± 3.4-2.1 ± 4.8
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.98 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.02 · 95% CI -2.12 to 2.17
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.71 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.35 · 95% CI -2.26 to 1.56
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.92 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.10 · 95% CI -2.10 to 2.31
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.98 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference of slope: 0.001 · 95% CI -0.08 to 0.08
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.66 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.02 · 95% CI -0.06 to 0.10
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.66 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.02 · 95% CI -0.10 to 0.06
Secondary24-2 Frequency Doubling Technology (FDT) - Foveal Sensitivity dB

24-2 FDT was used to evaluate retinopathy using visual field deficits. Foveal sensitivity is presented below. Foveal sensitivity is the measurement of the fovea's light detection ability. Lower values suggest visual field deficits.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · dB
24-2 Frequency Doubling Technology (FDT) - Foveal Sensitivity dB
dBBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Foveal Sensitivity27.7 ± 4.528.3 ± 3.526.9 ± 4.925.4 ± 5.9
3 Months--Foveal Sensitivity28.3 ± 5.328.3 ± 4.527.1 ± 4.126.4 ± 4.6
12 Months--Foveal Sensitivity28.1 ± 428.9 ± 3.625.9 ± 5.528.3 ± 4.6
24 Months--Foveal Sensitivity27 ± 5.328.2 ± 4.526.7 ± 526.5 ± 6.6
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.26 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.58 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.97 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
Secondary24-2 Frequency Doubling Technology (FDT) - Pattern SD

24-2 FDT was used to evaluate retinopathy using visual field deficits. Pattern SD (PSD) is presented below. PSD provides information about localized loss. A higher PSD indicates a non-uniform sensitivity loss and visual field deficit.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · dB
24-2 Frequency Doubling Technology (FDT) - Pattern SD
dBBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Patter SD3.4 ± 1.13.1 ± 1.13.3 ± 1.13.7 ± 1.3
3 Months-Patter SD3.1 ± 1.13.2 ± 1.33.3 ± 13.9 ± 1.7
12 Months-Patter SD3.2 ± 1.13.3 ± 1.73.5 ± 1.13.6 ± 1.6
24 Months-Patter SD3.2 ± 0.83.1 ± 0.73.5 ± 1.13.9 ± 1.7
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.25 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.98 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.88 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryRetinal Fundus Photography

As assessed by fundus photographs, participants were identified as either having retinopathy or not having retinopathy. Data is shown as number of people with retinopathy at a particular study visit.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Count of participants · Participants
Retinal Fundus Photography
ParticipantsBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline0111
3 Months0000
12 Months0000
24 Months0000
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Fisher Exact · p = 1 (The P-value tests whether the change in participant count (as either having retinopathy or not having retinopathy) from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Fisher Exact · p = 1 (The P-value tests whether the change in participant count (as either having retinopathy or not having retinopathy) from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Fisher Exact · p = 0.44 (The P-value tests whether the change in participant count (as either having retinopathy or not having retinopathy) from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryNerve Conduction Study (NCS) - Latency

Latency measures the time in millisecond between stimulation and the recording electrode. Was performed on sural, peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \>6.5 - Abnormal * Sural: 0 - No response, \>4.5 - Abnormal * Tibial: 0 - No response, \>6.1 - Abnormal

Time frame:
Baseline and 24 months
Reported as:
Mean · ms
Nerve Conduction Study (NCS) - Latency
msBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Peroneal distal motor latency (ms)4.6 ± 0.84.4 ± 0.64.4 ± 0.74.5 ± 1
Baseline-Sural peak latency (ms)3.8 ± 0.53.7 ± 0.43.6 ± 0.33.9 ± 0.4
Baseline-Tibial distal motor latency (ms)4.8 ± 0.64.9 ± 0.84.5 ± 0.64.7 ± 0.7
24 Months-Peroneal distal motor latency (ms)4.3 ± 0.54.4 ± 0.74.2 ± 0.74.2 ± 0.7
24 Months-Sural peak latency (ms)3.5 ± 0.43.5 ± 0.43.6 ± 0.63.4 ± 0.5
24 Months-Tibial distal motor latency (ms)4.3 ± 0.74.4 ± 0.84.3 ± 0.94.6 ± 1.1
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.83 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.05 · 95% CI -0.40 to 0.50
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.33 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.20 · 95% CI -0.62 to 0.21
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.75 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.06 · 95% CI -0.36 to 0.49
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.45 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.13 · 95% CI -0.49 to 0.23
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.13 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.24 · 95% CI -0.57 to 0.08
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.03 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.41 · 95% CI -0.79 to -0.03
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.05 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.50 · 95% CI -0.002 to 1.01
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.08 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.48 · 95% CI -0.07 to 1.03
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.38 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.21 · 95% CI -0.27 to 0.70
SecondaryNerve Conduction Study (NCS) - Motor Amplitude

Amplitude measures the height of electrical signal (waveform) in millivolts produced by the stimulated motor nerve. Was performed on peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \< 1.1 - Abnormal * Tibial: 0 - No response, \<1.1 - Abnormal

Time frame:
Baseline and 24 months
Reported as:
Mean · mV
Nerve Conduction Study (NCS) - Motor Amplitude
mVBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Peroneal amplitude (mV)5.21 ± 2.395.95 ± 3.055.18 ± 2.566.25 ± 4.13
Baseline-Tibial amplitude (mV)9.4 ± 3.599.16 ± 4.558.06 ± 4.47.59 ± 4.66
24 Months-Peroneal amplitude (mV)4.9 ± 2.116.23 ± 2.934.93 ± 2.025.11 ± 4.04
24 Months-Tibial amplitude (mV)9.65 ± 4.989.28 ± 4.758.54 ± 4.028.04 ± 4.22
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.48 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.31 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.23 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.65 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.69 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.69 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryNerve Conduction Study (NCS) - Sensory Amplitude

Amplitude measures the height of electrical signal (waveform) in microvolts produced by the stimulated sensory nerve. Was performed on sural nerve. No response and abnormal values indicate neuropathy. \* Sural: 0 - No response, \<4 - Abnormal

Time frame:
Baseline and 24 months
Reported as:
Mean · μV
Nerve Conduction Study (NCS) - Sensory Amplitude
μVBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Sural amplitude (µV)12.4 ± 510.8 ± 5.310.6 ± 4.79.1 ± 5.3
24 Months-Sural amplitude (µV)12.4 ± 6.114.2 ± 5.810.7 ± 5.710.6 ± 6.7
Statistical analysis
  • Bariatric Surgery/HIIT vs Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.82 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.26 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.62 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryNerve Conduction Study (NCS) - CV

Conduction velocity (V) measures the speed (m/s) at which the electrical impulse travels along the nerve. Was performed on peroneal nerves. No response and abnormal values indicate neuropathy. Abnormal values are \<36 or 39, depending on whether certain criteria applied to the participant. Data was not analyzed separately.

Time frame:
Baseline and 24 months
Reported as:
Mean · m/s
Nerve Conduction Study (NCS) - CV
m/sBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Peroneal CV (m/s)46.91 ± 4.1445.37 ± 4.2746.49 ± 4.3945.47 ± 6.38
24 Months-Peroneal CV (m/s)46.96 ± 5.5847.48 ± 4.2544.69 ± 5.4345.96 ± 5.24
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.82 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.27 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.52 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryNerve Conduction Study (NCS) - F Wave Index

F wave index measures the time in millisecond between stimulation at a distal (near the muscle) point and for the stimulus to travel to the spinal cord and back, allowing to assess the entire length of the nerve. Was performed on peroneal, and tibial nerves. No response and abnormal values indicate neuropathy. * Peroneal: 0 - No response, \>55 - Abnormal * Tibial: 0 - No response, \>55 - Abnormal

Time frame:
Baseline and 24 months
Reported as:
Mean · ms
Nerve Conduction Study (NCS) - F Wave Index
msBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline-Peroneal F wave index (ms)48.29 ± 6.9949.57 ± 4.5449.28 ± 5.7348.91 ± 9.35
Baseline-Tibial F wave index (ms)50.84 ± 8.8851.92 ± 5.7852.45 ± 5.450.8 ± 9.21
24 Months-Peroneal F wave index (ms)48.45 ± 4.5748.5 ± 5.448.95 ± 5.1850.07 ± 6.95
24 Months-Tibial F wave index (ms)50.56 ± 5.750.41 ± 6.0650.61 ± 5.3251.88 ± 5.12
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.32 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.43 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.48 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.75 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.09 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.03 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryCardiac Autonomic Neuropathy Testing-Deep Breathing/Exhalation to Inhalation (E:I) Ratio

Deep breathing/exhalation to inhalation (E:I) ratio were evaluated using PS monitor software. Values \< 1 are abnormal, indicative of cardiovascular autonomic neuropathy

Time frame:
Baseline and 24 months
Reported as:
Mean · ratio
Cardiac Autonomic Neuropathy Testing-Deep Breathing/Exhalation to Inhalation (E:I) Ratio
ratioBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline1.3 ± 0.11.2 ± 0.21.3 ± 0.21.2 ± 0.2
24 Months1.2 ± 0.21.3 ± 0.21.3 ± 0.21.2 ± 0.2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.79 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.02 · 95% CI -0.16 to 0.129
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.46 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.05 · 95% CI -0.2 to 0.01
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.24 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.01 · 95% CI -0.26 to 0.07
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.98 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.001 · 95% CI -0.01 to 0.01
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.49 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.002 · 95% CI -0.004 to 0.01
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.17 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.004 · 95% CI -0.002 to 0.01
SecondaryCardiac Autonomic Neuropathy Testing (30:15 Ratio)

Postural change-30:15 ratio was evaluated using PS monitor software. Values \< 1 are abnormal, indicative of cardiovascular autonomic neuropathy

Time frame:
Baseline and 24 months
Reported as:
Mean · ratio
Cardiac Autonomic Neuropathy Testing (30:15 Ratio)
ratioBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline1.1 ± 0.21.1 ± 01.1 ± 0.11.1 ± 0.1
24 Months1.2 ± 0.21.2 ± 0.21.2 ± 0.21.3 ± 0.2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.07 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.15 · 95% CI -0.01 to 0.31
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.72 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.024 · 95% CI -0.11 to 0.16
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.33 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.06 · 95% CI -0.06 to 0.19
SecondaryCardiac Autonomic Neuropathy Testing (Valsalva Ratio)

Valsalva ratio was evaluated using PS monitor software. Values \<= 1.10 are abnormal, indicative of cardiovascular autonomic neuropathy

Time frame:
Baseline and 24 months
Reported as:
Mean · ratio
Cardiac Autonomic Neuropathy Testing (Valsalva Ratio)
ratioBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline1.5 ± 0.21.5 ± 0.21.4 ± 0.21.4 ± 0.2
24 Months1.3 ± 0.21.4 ± 0.31.3 ± 0.21.4 ± 0.3
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.46 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.064 · 95% CI -0.11 to 0.24
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.15 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.13 · 95% CI -0.04 to 0.31
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.20 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.11 · 95% CI -0.06 to 0.30
SecondaryParticipants With Probable Polyneuropathy as Defined by the Toronto Definition of Probable Neuropathy

Toronto definition of probable neuropathy is having at least 2 out of 3 of the following: abnormal sensory examination, reflexes, and patient-reported symptoms. Data is reported as number of participants who, under the Toronto definition, were identified as having probable polyneuropathy.

Time frame:
24 months
Reported as:
Number · participants with probable neuropathy
Participants With Probable Polyneuropathy as Defined by the Toronto Definition of Probable Neuropathy
participants with probable neuropathyBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline65911
24 Months9779
Statistical analysis
  • Bariatric Surgery/HIIT · Wilcoxon (Mann-Whitney) · p = 0.07 · Wilcoxon test statistic: 10
  • Bariatric Surgery/Routine Exercise · Wilcoxon (Mann-Whitney) · p = 0.34 · Wilcoxon test statistic: 3
  • No Bariatric Surgery/HIIT · Wilcoxon (Mann-Whitney) · p = 0.42 · Wilcoxon test statistic: 2.5
  • No Bariatric Surgery/Routine Exercise · Wilcoxon (Mann-Whitney) · p = 0.77 · Wilcoxon test statistic: 9
SecondaryMichigan Neuropathy Screening Instrument (MNSI)

MNSI questionnaire is scored from 0-15, score \> 4 indicate neuropathy, higher scores indicate worse neuropathy. A score of 1 point is given for answers of "yes" for questions 1-6, 8-12, 14, and 15 and "no" for questions 7 and 13.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Michigan Neuropathy Screening Instrument (MNSI)
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline Questionnaire2.5 ± 2.42.5 ± 1.72.4 ± 2.22.8 ± 2.1
3 Months Questionnaire2.5 ± 2.72 ± 1.92.5 ± 2.72.3 ± 2.2
12 Months Questionnaire2.7 ± 2.92.1 ± 2.22.3 ± 22.8 ± 2.1
24 Months Questionnaire3.2 ± 2.62.3 ± 21.8 ± 1.72.8 ± 2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.21 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.61 · 95% CI -1.5 to 0.35
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.85 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.09 · 95% CI -0.98 to 0.80
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.37 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.46 · 95% CI -0.58 to 1.50
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.78 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 1.00 · 95% CI 0.99 to 1.02
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.53 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.99 · 95% CI 0.98 to 1.01
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.08 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.98 · 95% CI 0.96 to 1.00
SecondaryMichigan Neuropathy Screening Instrument (MNSI) - Exam

MNSI exam is scored from 0-8, score \>= 2.5 indicate neuropathy. Higher scores indicate worse neuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Michigan Neuropathy Screening Instrument (MNSI) - Exam
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline Exam1 ± 1.40.9 ± 1.21.1 ± 1.41.3 ± 1.7
3 Months Exam1 ± 1.40.4 ± 0.71.2 ± 1.81.5 ± 1.6
12 Months Exam1.1 ± 1.31 ± 1.31.1 ± 1.71.4 ± 1.7
24 Months Exam0.9 ± 1.30.6 ± 0.91.3 ± 1.81.8 ± 1.5
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.01 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.04 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.47 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.18 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.98 · 95% CI 0.96 to 1.01
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.52 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.99 · 95% CI 0.96 to 1.02
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.87 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 1.00 · 95% CI 0.97 to 1.02
SecondaryMichigan Neuropathy Screening Instrument (MNSI) - Index

The Michigan Neuropathy Screening Instrument (MNSI) index is a weighted composite score computed using the sum of the b-coefficients for all items within the MNSI questionnaire (15 questions) and MNSI exam (4 physical/visual exam). Range: -0.93, 7.39 Values \> 2.5407 are indicative of clinical neuropathy

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · MNSI Score
Michigan Neuropathy Screening Instrument (MNSI) - Index
MNSI ScoreBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline Index1.6 ± 1.31.5 ± 0.91.4 ± 1.31.8 ± 1.3
3 Months Index1.6 ± 1.31.1 ± 11.7 ± 1.41.8 ± 1.5
12 Months Index1.7 ± 1.61.3 ± 1.11.6 ± 1.32 ± 1.5
24 Months Index1.7 ± 1.51.5 ± 1.51.9 ± 1.31.9 ± 1.2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.20 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.57 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.61 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.)
SecondaryUtah Early Neuropathy Score (UENS)

UENS is a composite score with five sections measuring multiple clinical measures of nerve injury. Sections are scored separately for each side (Right vs Left), and the total score is the sum across everything. Range: 0-42, higher score represents more severe polyneuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Utah Early Neuropathy Score (UENS)
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline UENS Total Score2.4 ± 4.11.6 ± 2.62.4 ± 3.73.5 ± 4.6
3 Months UENS Total Score1.7 ± 2.81.8 ± 3.52.9 ± 5.23 ± 4.3
12 Months UENS Total Score3.9 ± 4.92.8 ± 3.83.2 ± 5.24.8 ± 6.3
24 Months UENS Total Score2.8 ± 3.72.5 ± 3.62.9 ± 2.33.8 ± 4.8
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.44 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.73 · -1.2% CI -1.2 to 2.67
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.97 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.03 · 95% CI -2.16 to 2.10
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.71 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.40 · 95% CI -1.78 to 2.58
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.99 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 1.00 · 95% CI 0.98 to 1.02
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.88 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 1.00 · 95% CI 0.98 to 1.02
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.09 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.99 · 95% CI 0.97 to 1.00
SecondaryModified Toronto Neuropathy Score (mTNS)

mTNS is a scale of 0-33 that measures neuropathy symptoms and exam findings. Higher scores indicate more severe polyneuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Modified Toronto Neuropathy Score (mTNS)
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline3.8 ± 7.71.5 ± 2.62.1 ± 3.43.5 ± 5.7
3 Months2.1 ± 4.21.3 ± 1.52.1 ± 4.42.8 ± 4.7
12 Months3.5 ± 5.91.8 ± 32.3 ± 4.13.4 ± 5.9
24 Months4.4 ± 6.42.6 ± 2.91.4 ± 1.93.2 ± 3.9
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.78 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.52 · 95% CI -3.41 to 4.45
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.63 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.59 · 95% CI -3.14 to 1.95
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.43 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 1.01 · 95% CI -1.55 to 3.58
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.43 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.99 · 95% CI 0.98 to 1.01
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.83 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 1.00 · 95% CI 0.98 to 1.02
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = <0.01 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.97 · 95% CI 0.94 to 0.99
SecondarySurvey of Autonomic Symptoms (SAS)

SAS evaluates the presence and magnitude of autonomic symptoms. Total impact score ranges from 0-60 (or up to 55 for participants to whom certain criteria did not apply). Higher score indicates worse autonomic neuropathy

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Survey of Autonomic Symptoms (SAS)
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline4.7 ± 4.15 ± 4.35.1 ± 4.75.1 ± 5.1
3 Months8.2 ± 8.34.9 ± 4.23.4 ± 3.84.8 ± 4.3
12 Months5.3 ± 7.25.1 ± 4.14.5 ± 3.66.2 ± 7.3
24 Months5.3 ± 7.18.4 ± 45.3 ± 5.36.2 ± 5.7
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.84 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.54 · 95% CI -6.68 to 5.59
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.48 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 2.70 · 95% CI -7.57 to 12.97
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.64 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.87 · 95% CI -4.94 to 3.18
SecondaryDiabetic Neuropathy Score (DNS)

DNS is a questionnaire of neuropathy symptoms. Score ranges 0-4, \>/=1 indicates polyneuropathy. 0 indicates no polyneuropathy.

Time frame:
Baseline, 3 month, 12 months and 24 months
Reported as:
Mean · score on a scale
Diabetic Neuropathy Score (DNS)
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline1.1 ± 1.30.9 ± 0.90.8 ± 11.1 ± 1.4
3 Months1.1 ± 1.40.6 ± 10.8 ± 1.20.9 ± 1.4
12 Moths1 ± 1.30.6 ± 0.90.8 ± 1.20.9 ± 1.1
24 Months1.3 ± 1.50.6 ± 10.7 ± 0.81.1 ± 1.4
Statistical analysis
  • Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.69 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.2
  • Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.24 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Median difference (net): -0.3
  • No Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.45 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.2
  • No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.84 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.1
SecondaryShort Form McGill Pain Questionnaire

Sum of the sensory score (0-30) and affective score (0-15) for a total score of 0-45. A higher score represents greater pain present.

Time frame:
Baseline, 3 months, 12 months, 24 months
Reported as:
Mean · score on a scale
Short Form McGill Pain Questionnaire
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline3.7 ± 4.43.1 ± 4.42.7 ± 4.13.5 ± 5.5
3 Months3.8 ± 7.72.1 ± 3.62.6 ± 4.23.5 ± 6
12 Months3.3 ± 8.52.3 ± 3.42.4 ± 2.82.6 ± 4.5
24 Months5.2 ± 6.62.5 ± 4.52.1 ± 2.62.2 ± 3.8
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.09 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Mean difference (net): -2.60 · 95% CI -5.66 to 0.44
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.56 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Mean difference (net): -0.97 · 95% CI -4.36 to 2.41
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.21 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Mean difference (net): -1.72 · 95% CI -4.5 to 1.05
SecondaryNumerical Rating Scale for Pain

Participant reported pain scale with range 0-10, higher score indicates more pain.

Time frame:
Baseline, 3 months, 12 months, 24 months
Reported as:
Mean · score on a scale
Numerical Rating Scale for Pain
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline2.2 ± 2.62.7 ± 3.42.5 ± 3.73.8 ± 4
3 Months3.3 ± 4.22.7 ± 3.74.2 ± 4.23.6 ± 4.2
12 Months2.9 ± 4.03.5 ± 4.26.1 ± 4.43.8 ± 4.4
24 Months3.8 ± 4.04.7 ± 4.74.5 ± 4.35 ± 4.2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.62 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group)
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.92 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group)
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.90 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group)
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.46 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.02 · 95% CI -0.06 to 0.03
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.47 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.02 · 95% CI -0.06 to 0.03
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.91 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: 0.003 · 95% CI -0.04 to 0.05
SecondaryNeuropathy Quality of Life (NeuroQOL)

Neuropathy Quality of Life (NeuroQOL) evaluates symptoms and function in regard to quality of life over the past four weeks. Range 1-15, higher score indicates neuropathy having a greater impact on quality of life.

Time frame:
Baseline, 3 months, 12 months, and 24 months
Reported as:
Mean · NeuroQOL Score
Neuropathy Quality of Life (NeuroQOL)
NeuroQOL ScoreBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline2.62 ± 2.342.13 ± 1.122.1 ± 0.942.71 ± 1.98
3 Months2.49 ± 2.371.62 ± 0.51.93 ± 0.972.7 ± 1.5
12 Months2.23 ± 2.481.62 ± 0.432.21 ± 0.872.42 ± 1.26
24 Months3.07 ± 3.021.86 ± 0.861.7 ± 0.582.55 ± 1.98
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.83 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.06 · 95% CI -0.53 to 0.65
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.97 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.01 · 95% CI -0.76 to 0.78
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.76 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.09 · 95% CI -0.73 to 0.54
Secondary8 Foot Get Up and Go Test

This test measures in seconds how long it takes the participant to stand up from a seated position, walk around a cone places 8 feet away, and return to the chair and sit down. Less time indicates better speed, agility, and balance when moving.

Time frame:
Baseline, 3 months, 12 months, and 24 months
Reported as:
Mean · Seconds
8 Foot Get Up and Go Test
SecondsBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline6.2 ± 1.56.1 ± 16.4 ± 1.26.6 ± 1.4
3 Months6 ± 1.15.9 ± 0.86.4 ± 1.36.8 ± 1.5
12 Months6.2 ± 1.25.6 ± 0.76.6 ± 1.66.8 ± 1.3
24 Months7.1 ± 3.96 ± 0.96.5 ± 17 ± 1.2
Statistical analysis
  • Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.58 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): 0.5
  • Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.80 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.1
  • No Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.86 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): 0.1
  • No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.46 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): 0.3
SecondaryBerg Balance Scale

Berg Balance Scale measures participants' ability to balance and avoid falls. Scores range from 0-56, higher score indicates less likely to fall.

Time frame:
Baseline, 3 months, 12 months, and 24 months
Reported as:
Mean · score on a scale
Berg Balance Scale
score on a scaleBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline55.41 ± 1.1655.53 ± 1.0255.41 ± 1.1654.57 ± 1.93
3 Months55.48 ± 1.555.47 ± 1.2755.48 ± 1.554.81 ± 1.73
12 Months54.88 ± 2.1255.41 ± 1.4854.88 ± 2.1254.65 ± 1.6
24 Months55.15 ± 2.3655.5 ± 1.255.15 ± 2.3655 ± 1.89
Statistical analysis
  • Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.38 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.58
  • Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.72 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): 0.11
  • No Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.55 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): -0.31
  • No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.28 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant) · Mean difference (net): 0.57
SecondaryModified Falls Efficacy Scale - Fall Evaluation

Patient response indicating if they have fallen in the last year. Data is shown as number of people who have fallen in the last year.

Time frame:
Baseline, 3 months, 12 months, and 24 months
Reported as:
Count of participants · Participants
Modified Falls Efficacy Scale - Fall Evaluation
ParticipantsBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline89912
3 Months8885
12 Months72210
24 Months6876
Statistical analysis
  • Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.54 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant)
  • Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 1.00 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant)
  • No Bariatric Surgery/HIIT · t-test, 2 sided · p = 0.77 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant)
  • No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.24 (The P-value tests whether the within-participant change in the group from baseline to 2 years is significant)
SecondaryNeurothesiometer

Neurothesiometer is placed on the bottom of the great toe, and slowly increased until participant reports they can feel the vibration. The greater the microns, the less feeling the participant has, suggestive of worse sensory function. Value \> 25 Microns is indicative of neuropathy. There is no known maximum range. Lower values indicate better sensory function.

Time frame:
Baseline, 3 months, 12 months, and 24 months
Reported as:
Mean · Microns
Neurothesiometer
MicronsBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline8.7 ± 8.310.2 ± 921.1 ± 47.420.2 ± 34.9
3 Months9.7 ± 11.38 ± 5.620.8 ± 47.715.4 ± 27
12 Months12.1 ± 12.89.9 ± 1519.1 ± 47.723.3 ± 48.3
24 Months13.6 ± 14.28 ± 6.212 ± 11.321.7 ± 39.5
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.36 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -2.00 · 95% CI -6.37 to 2.36
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = <0.01 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 4.5 · 95% CI 1.31 to 7.71
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.30 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 5.62 · 95% CI -5.37 to 16.63
SecondaryNIH Toolbox Cognitive Battery

NIH Toolbox Cognition Fluid (Range: 0-100) - Composite score derived as an average across five cognitive domains. It's a fully adjusted T-score comparing the participant to a nationally representative sample, stratified by age and other demographics. Individual domain scores are fully adjusted T score with range 0-100 and measures the following- * Inhibitory Control and Attention - executive function, attention . * Dimensional Change Card Sort - executive function * Picture Sequence Memory - episodic memory * List Sorting Working Memory - working memory * Pattern Comparison - processing speed A T-score of 50 represents the population mean. A score of 60 indicates that the participant is 1 SD above the national average for individuals with similar demographic characteristics Higher scores reflect better cognitive functionality. No set clinical threshold, scores above mean indicate above average cognition for a given age group.

Time frame:
Baseline and at 24 months
Reported as:
Mean · T-score
NIH Toolbox Cognitive Battery
T-scoreBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline Inhibitory Control and Attention Test42.6 ± 6.844 ± 8.342.7 ± 7.843 ± 8.9
Baseline Dimensional Change Card Sort Test51.6 ± 12.954.6 ± 11.554.5 ± 13.251.8 ± 12.3
Baseline Picture Sequence Memory Test56.2 ± 11.855.8 ± 12.255.6 ± 1254.2 ± 8.5
Baseline List Sorting Working Memory Test54.8 ± 10.151.7 ± 9.353.3 ± 10.850.3 ± 8.2
Baseline Pattern Comparison Processing Speed Test48.9 ± 13.149.4 ± 12.251 ± 1550.4 ± 13.9
Baseline Cognition Fluid Composite51.2 ± 12.351.6 ± 11.852.1 ± 11.249.8 ± 11.3
24 Months Inhibitory Control and Attention Test42.9 ± 9.344.3 ± 7.644.2 ± 8.243.9 ± 8.5
24 Months Dimensional Change Card Sort Test53.7 ± 12.553.7 ± 13.556.7 ± 1154.6 ± 10.9
24 Months Picture Sequence Memory Test55.9 ± 10.854.7 ± 1358.7 ± 10.856.3 ± 10.8
24 Months List Sorting Working Memory Test56.6 ± 10.152.1 ± 8.654.4 ± 7.550.7 ± 11.4
24 Months Pattern Comparison Processing Speed Test52.7 ± 13.846.7 ± 16.748.8 ± 13.447.3 ± 15.7
24 Months Cognition Fluid Composite53.5 ± 12.250.4 ± 11.253.9 ± 9.150.6 ± 10.2
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.16 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 3.14 · 95% CI -1.30 to 7.58
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.33 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 1.91 · 95% CI -2.05 to 5.88
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.49 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 1.43 · 95% CI -2.72 to 5.59
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.35 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 2.97 · 95% CI -3.48 to 9.44
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.10 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 5.6 · 95% CI -3.48 to 9.44
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.32 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 3.24 · 95% CI -3.34 to 9.82
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.49 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 2.4 · 95% CI -4.57 to 9.37
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.30 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 3.2 · 95% CI -3.03 to 9.56
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.86 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Median difference (net): 0.49 · 95% CI -5.40 to 6.38
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.88 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.42 · 95% CI -5.39 to 6.24
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.83 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.60 · 95% CI -5.14 to 6.31
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.81 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.62 · 95% CI -6.02 to 4.76
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.12 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -5.29 · 95% CI -12.1 to 1.57
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.63 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -1.84 · 95% CI -9.53 to 5.84
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.40 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -2.87 · 95% CI -9.80 to 4.05
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.65 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 1.04 · 95% CI -3.63 to 5.73
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.27 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 2.68 · 95% CI -2.17 to 7.54
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.90 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.27 · 95% CI -4.10 to 4.65
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.85 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.02 · 95% CI -0.21 to 0.17
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.28 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Interaction term for difference in slope: -0.10 · 95% CI -0.29 to 0.09
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · Mixed Models Analysis · p = 0.99 (The P-value tests for association between the outcome and treatment at each visit, compared to the no-treatment group) · Mean difference (net): 0.001 · 95% CI -0.18 to 0.19
SecondaryRey Auditory Verbal Learning Test

Used to evaluate verbal learning and memory using a list of 15 unrelated words presented to the participant over repeat trial. Includes 3 independent scales: * Auditory Learning (Total recall) - Measures memory and learning ability. Raw score range (0- 75) * Delayed Recall - Measures long term memory retention. Raw score range (0-15) * Recognition - Measures ability to recognize previously learned information. Raw score range (0-15). * Raw scores were converted to age-standardized Z-scores using 10-year age bands (e.g., 20-29, 30-39, 40-49, etc.), with a mean of 0 and standard deviation of 1. * A Z-score of 0 represents the population mean * For each scale, scores above 0 are better. Standard deviations above the mean indicates a better learning and memory ability for a given age group. No set clinical threshold, scores above mean indicate above average cognition for a given age group.

Time frame:
Baseline and at 24 months
Reported as:
Mean · Z-score
Rey Auditory Verbal Learning Test
Z-scoreBariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/HIITNo Bariatric Surgery/Routine Exercise
Baseline Auditory Learning0.1 ± 1.20.3 ± 1.20.4 ± 0.80.4 ± 1
Baseline Delayed Recall0 ± 1.1-0.2 ± 1.10.1 ± 0.9-0.1 ± 1
Baseline Recognition0.7 ± 0.80.6 ± 0.80.7 ± 1.20.7 ± 0.9
24 Months Auditory Learning-0.2 ± 1.30.2 ± 1.20.4 ± 10 ± 1.1
24 Months Delayed Recall-0.4 ± 1-0.1 ± 10.2 ± 0.9-0.1 ± 1.1
24 Months Recognition0.6 ± 1.20.9 ± 0.80.8 ± 1.20 ± 1
Statistical analysis
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.57 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.19 · 95% CI -0.87 to 0.49
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.33 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.26 · 95% CI -0.81 to 0.28
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.22 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Median difference (net): -0.38 · 95% CI -1.00 to 0.23
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.27 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.29 · 95% CI -0.23 to 0.81
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.54 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.16 · 95% CI -0.69 to 0.37
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.93 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.02 · 95% CI -0.57 to 0.53
  • Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.64 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.14 · 95% CI -0.46 to 0.74
  • Bariatric Surgery/Routine Exercise vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.37 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): -0.21 · 95% CI -0.70 to 0.27
  • No Bariatric Surgery/HIIT vs No Bariatric Surgery/Routine Exercise · t-test, 2 sided · p = 0.88 (The P-value tests whether the within-participant change in the outcome from baseline to 2 years differs between the treatment and no-treatment groups.) · Mean difference (net): 0.04 · 95% CI -0.59 to 0.69

Adverse events

Collected over 2 years. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Bariatric Surgery/HIIT0/35 (0%)0/35 (0%)0/35 (0%)
No Bariatric Surgery/HIIT0/35 (0%)0/35 (0%)2/35 (5.7%)
Bariatric Surgery/Routine Exercise0/35 (0%)0/35 (0%)1/35 (2.9%)
No Bariatric Surgery/Routine Exercise0/35 (0%)0/35 (0%)0/35 (0%)
Most frequent other events
Most frequent other events
EventBariatric Surgery/HIITNo Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseNo Bariatric Surgery/Routine Exercise
Infection at Skin Biopsy SiteInfections and infestations0/351/351/350/35
Injury During ExerciseInjury, poisoning and procedural complications0/351/350/350/35

Baseline characteristics

Data was collected for participants who were randomized in the study

Age, Continuous
Age, Continuous(years)No Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseBariatric Surgery/HIITNo Bariatric Surgery/Routine ExerciseTotal
Median50.54 ± 7.5649.66 ± 6.9849.91 ± 5.7751.14 ± 8.0850.31 ± 7.1
Sex: Female, Male
Sex: Female, Male(Participants)No Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseBariatric Surgery/HIITNo Bariatric Surgery/Routine ExerciseTotal
Female29262825108
Male6971032
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)No Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseBariatric Surgery/HIITNo Bariatric Surgery/Routine ExerciseTotal
Hispanic or Latino20013
Not Hispanic or Latino33353534137
Unknown or Not Reported00000
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)No Bariatric Surgery/HIITBariatric Surgery/Routine ExerciseBariatric Surgery/HIITNo Bariatric Surgery/Routine ExerciseTotal
Asian00011
Bi/Multi Racial Non-Hispanic00101
Black13251434
Hispanic10012
Hispanic White10001
Middle Eastern00011
Native-American00011
Native-American/Black11002
Non-Hispanic White1932291797
08

Study locations

1 site
  • University Of Michigan
    Ann Arbor, Michigan 48109, United States
09

References and documents

Publications

  • Reynolds EL, Koenig F, Watanabe M, Kwiatek A, Elafros MA, Stino A, Henderson D, Herrmann DN, Feldman EL, Callaghan BC. Comparison of intraepidermal nerve fiber density and confocal corneal microscopy for neuropathy. Ann Clin Transl Neurol. 2024 Dec;11(12):3115-3124. doi: 10.1002/acn3.52218. Epub 2024 Oct 12. PubMed 39394845 ↗

Study documents

PDFs hosted by the registry, ClinicalTrials.gov.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Sep 17, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT03617185
Lead sponsor
University of Michigan
Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Responsible party
Brian Callaghan (Fovette E Dush Early Career Professor and Assistant Professor of Neurology, University of Michigan) — Principal investigator
First posted
Aug 6, 2018
Start date
Jul 27, 2018
Primary completion
Aug 1, 2024
Completion
Aug 1, 2024
Results posted
Oct 29, 2025
Last update
Sep 17, 2026

Study contacts

Brian C Callaghan, MD, MS
principal investigator · University of Michigan, Department of Neurology

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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