CClinicalTrials.gg
CompletedNCT04614168Updated Jan 28, 2026Results posted

Maximising Time With a Normal Blood Glucose to Restore the Glucagon Response in Type 1 Diabetes

An interventional study of Stepped hyperinsulinaemic-hypoglycaemic clamp study and Insulin pump in Type 1 Diabetes, Type 1 Diabetes Mellitus With Hypoglycemia and Hypoglycemia, sponsored by University of Edinburgh. Completed at 1 site in United Kingdom. Open to participants aged 21 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-01-28.

Sponsored by University of Edinburgh · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
24
Allocation
Randomized
Ages
21 Years to 65 Years
Sex
All
01

Study summary

Almost all people who have had type 1 diabetes for 5 years have a defect in secretion of the hormone Glucagon. This hormone is involved in the body's response to low blood glucose (hypoglycaemia). It works by releasing glucose stores from the liver to bring the blood glucose back to normal. This defect therefore increases the risk of severe hypoglycaemia. The reason for this Glucagon defect in people with Type 1 diabetes is currently unknown.

This study aims to look at the Glucagon response to hypoglycaemia in 24 people with type 1 diabetes to ascertain whether tight blood glucose control over a period of time improves this response. The investigators aim to achieve good blood glucose control using new generation Automated Insulin Delivery systems (AIDs). This system is made of: an insulin pump, a continuous glucose monitor (CGM) and an algorithm that allows adjustment of insulin delivery based on the blood glucose readings from the CGM. This is the most up to date technology that there is in the management of type 1 diabetes. However, people using this technology often still have problems with high blood glucose after eating. To ensure a very good blood glucose control participants will also follow a low carbohydrate diet to prevent this blood glucose rise after meals.

The Glucagon response to low blood glucose will be measured at zero and eight months using the hyperinsulinaemic hypoglycaemic clamp technique.

Read the detailed description

This is a feasibility pilot study involving 24 participants with type 1 diabetes. Participants will be recruited from the local type 1 diabetes clinic and insulin pump waiting list. Each participant will enter the trial for a period of 8 months. The investigators aim to test if maximising time in glycaemic range (blood glucose 3.9-10 mmol/L) will restore the glucagon response to insulin-induced hypoglycaemia.

After signing informed consent participants will be screened for eligibility against the inclusion and exclusion criteria.

Those who are eligible will have an initial 20-day period of baseline blood glucose data collection. This will be achieved using a blinded continuous glucose monitoring (CGM) device. Participants will continue on their pre-trial diabetes care during this period and will be required to monitor their own blood glucose as normal.

The participants will be split into two groups using stratified sampling to match for: age, gender and BMI.

Group 1 will be the control group. Participants in this group will continue on standard diabetes care for the duration of the trial. Participants will be required to undertake two further periods of blinded CGM monitoring at 4 and 8 months.

Group 2 will be the intervention group. Participants in this group will be placed on the automated insulin delivery (AID) system and asked to follow a low carbohydrate diet of 30-40g of carbohydrate per main meal portion. The AID system will consist of: a Tandem t:slim X2 insulin pump with control IQ technology and a Dexcom G6 continuous glucose monitor. After receiving training on the use of the devices these participants will enter a 2 week study run-in period to become accustomed to the devices and so that device settings can be optimised. As a safety measure these participants will be asked to measure blood ketones at least once daily throughout the trial. Study staff will monitor the data from the participants study devices throughout the trial and adjust settings as required to maximise time in glycaemic range.

At the beginning and end of the trial all participants will undergo a hyperinsulinaemic hypoglycaemic clamp study to measure their counterregulatory hormone response to hypoglycaemic. Participants will also undergo cognitive tests and assessment of hypoglycaemic awareness during each clamp study.

02

Conditions studied

  • Type 1 Diabetes
  • Type 1 Diabetes Mellitus With Hypoglycemia
  • Hypoglycemia
  • Hypoglycemia Unawareness
  • Glucagon Deficiency
  • Insulin Hypoglycemia

Keywords

  • Type 1 diabetes
  • Hypoglycaemia
  • Hypoglycemia
  • Glucagon
  • Insulin
  • Low carbohydrate diet
  • Stable isotope
03

In context

Diabetes Mellitus, Type 1

3,522 studies on the registry are indexed under Diabetes Mellitus, Type 1; 577 are open to participants now.

This study's enrollment of 24 is below the median of 40 across 2,649 interventional studies indexed under Diabetes Mellitus, Type 1.

Browse Diabetes Mellitus, Type 1 studies →

Lead sponsor

University of Edinburgh is the lead sponsor of 393 studies on the registry; 64 are open to participants now.

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

04

Who can participate

Ages eligible
21 Years to 65 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Participants with Type 1 diabetes with C-peptide levels less than 200pmol/L.
  • Type 1 diabetes for 5 years or more.
  • HbA1c greater than or equal to 53 mol/mol.
  • Normal renal function.
  • Normal thyroid function.
  • Gold Score 4-7 (indicating impaired awareness of hypoglycaemia)
  • Willingness to monitor blood ketones daily.
  • Use of freestyle libre device is permitted at study entry and may be continued in participants in group 1

Exclusion criteria

Exclusion Criteria:

  • Current use of a non-approved closed loop / AID system or those on a predictive low glucose suspend insulin pump.
  • Proliferative retinopathy
  • Regular use of real time CGM in the preceding 3 months.
  • History of Diabetic ketoacidosis in the preceding 6 months.
  • Severe hypoglycaemic episode requiring external assistance in the preceding 6 months.
  • Inability to safely use technology used in this study (e.g. impaired vision, memory or dexterity that prevents safe operation of CGM or insulin pump.)
  • Inability to support the technology requirements for the study (e.g. unable to upload study device at home)
  • History of Haemophilia, Cystic Fibrosis, pancreatic disease or complete pancreatectomy, ischaemic heart disease, epilepsy or hypoglycaemia induced seizure
  • History of severe reaction or allergy to adhesive necessary to this study.
  • Unable to adhere to study timetable.
  • Unable to give informed consent.
  • Pregnancy. We will perform a pregnancy test on all eligible participants at baseline.
  • Concurrent use of any non-insulin glucose-lowering agent (including GLP-1 agonists, Symlin, DPP-4 inhibitors, SGLT-2 inhibitors, sulfonylureas. These may lower insulin requirements and predispose to diabetic ketoacidosis.
  • Concurrent use of medication that may affect blood glucose such as SSRIs
  • A condition, which in the opinion of the investigator, would put the patient or study at risk
  • HbA1c greater than or equal to 75 mmol/mol
05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
24 participants (actual)

Study arms

  • Active comparator
    Group 1 - Standard Care

    This group will continue on their standard diabetes care. They will be required to undergo three periods of blinded continuous glucose monitoring each lasting 20-days at: baseline, 4 months and 8 months. Participants in this group will undergo a hyperinsulinaemic hypoglycaemic clamp study at baseline and 8 months. They will also complete quality of life and diabetes treatment questionnaires at baseline and 8 months.

    Procedure: Stepped hyperinsulinaemic-hypoglycaemic clamp study · Device: Blinded continuous glucose monitor · Procedure: Stable isotope studies- D2 Glucose and D5 Glycerol

  • Experimental
    Group 2- Automated insulin delivery and low carbohydrate diet

    This group will be placed on an automated insulin delivery system: Tandem t:slim x2 insulin pump with Control IQ technology and Dexcom G6 continuous glucose monitor. They will also be asked to follow a low-carbohydrate diet of 30-40g of carbohydrate per main meal. At baseline they will have a 20-day period of blinded continuous glucose monitoring. Participants in this group will undergo a stepped hyperinsulinaemic hypoglycaemic clamp study at baseline and 8 months. They will also complete quality of life and diabetes treatment questionnaires at baseline and 8 months.

    Procedure: Stepped hyperinsulinaemic-hypoglycaemic clamp study · Device: Insulin pump · Device: Continuous glucose monitor · Other: Low carbohydrate diet · Device: Blinded continuous glucose monitor · Procedure: Stable isotope studies- D2 Glucose and D5 Glycerol

Interventions

  • ProcedureStepped hyperinsulinaemic-hypoglycaemic clamp study

    Participants will commence on a primed insulin infusion at a constant rate of 60mU/m2/min along with a variable rate 20% glucose infusion. Participants will have their blood glucose monitored every 5 minutes. The glucose infusion will be altered to achieve the desired blood glucose plateaus of: 5mmol/l, 3mmol/l and 2.5mmol/l. Each plateau will be held for 40 minutes. During each plateau blood samples will be taken on three occasions for: glucagon, cortisol, adrenaline, noradrenaline, D2 glucose and D5 glycerol. On two occasions during each plateau participants will complete the Edinburgh hypoglycaemia scale and the following cognitive tests: trail making test, digit span test, digit symbol substitution test and four choice reaction time test. At the end of the clamp study the insulin infusion will be discontinued and the blood glucose will be allowed to rise to the normal range. Participants will consume lunch before leaving the clinical research facility.

  • DeviceInsulin pump

    Insulin pump with a built-in algorithm that allows it to work with a CGM device to adjust insulin delivery based on CGM readings.

    Also known as: Tandem t:slim x2 with Control IQ technology

  • DeviceContinuous glucose monitor

    Continuous glucose monitoring device that sends data to the insulin pump to allow the algorithm to adjust insulin delivery. Participants are able to see the glucose data from the device when it is used in open mode.

    Also known as: Dexcom G6

  • OtherLow carbohydrate diet

    30-40g of carbohydrate per main meal portion.

  • DeviceBlinded continuous glucose monitor

    Allows data on blood glucose to be collected without values altering the behaviour of the participant. Participants have to continue to monitor their own blood glucose while wearing the device in the blinded mode.

    Also known as: Dexcom G6

  • ProcedureStable isotope studies- D2 Glucose and D5 Glycerol

    These studies will take place at the same time as the hyperinsulinaemic hypoglycaemic clamp studies. Participants will receive a priming dose of each stable isotope followed by a continuous infusion for the remainder of the clamp study.

06

What researchers measure

Primary outcomes

  1. The Change in Plasma Glucagon Levels (Pmol/L) Measured During Normoglycaemic and Hypoglycaemia

    The delta glucagon concentration (pmol/L) from plateau 1 (normoglycaemia- 5.0 mmol/L) to plateau 3 (hypoglycaemia- 2.5 mmol/L). The physiological response in health would be for an increase in glucagon secretion from normo- to hypoglycaemia.

    Time frame: Clamp 1 at baseline and clamp 2 at 8 months

Secondary outcomes

  1. Time in Glycaemic Range (3.9-10mmol/L)

    Percentage time spent in target glycaemic range.

    Time frame: Baseline (study entry), midpoint at 4 months and endpoint at 8 months

  2. Time Spent Below the Target Glycaemic Range (<3.9mmol/L)

    Percentage of time spent below the target glycaemic range

    Time frame: Baseline (study entry), midpoint at 4 months and endpoint at 8 months

  3. Time Spent Above the Target Glycaemic Range (>10mmol/L)

    Percentage of time spent above the target glycaemic range

    Time frame: Baseline (study entry), midpoint at 4 months and endpoint at 8 months

  4. The Change in Plasma Cortisol (ng/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

    Delta cortisol from P1 (5.0 mmol/L) to P3 (2.5 mmol/L)

    Time frame: Clamp 1 at baseline and clamp 2 at 8 months

  5. The Change in Plasma Adrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

    Delta adrenaline from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L)

    Time frame: Clamp 1 at baseline and clamp 2 at 8 months

  6. The Change in Plasma Noradrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

    The change in noradrenaline concentration from plateau 1 (5 mmol/L) to plateau 3 (2.5 mmol/L).

    Time frame: Clamp 1 at baseline and clamp 2 at 8 months

  7. Endogenous Glucose Production

    The change in the glucose rate of appearance from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L)

    Time frame: Clamp 1 at baseline and clamp 2 at 8 months

  8. HbA1c

    Delta HbA1c from baseline to study endpoint.

    Time frame: Baseline (study entry) endpoint (8 months)

  9. Change in Quality of Life at Trial Entry and End.

    Measured using the EQ5D-5L- -VAS. Number on scale of 0-100 to assess wellbeing on that day. 100 being the most well.

    Time frame: Baseline (study entry) endpoint (8 months)

  10. Change in Emotional Distress Related to Diabetes at Trial Entry and End.

    Diabetes Distress Scale (DDS-1)- a 28-item self-reporting scale. Each item can be scored from 1 (not a problem) to 6 (a very serious problem). This questionnaire will be completed at study entry and study end. Data presented is the DDS total score.

    Time frame: Baseline (study entry) endpoint (8 months)

  11. Change in Fear of Hypoglycaemic

    Measured using the Hypoglycaemia Fear Survey (HFS)- this survey consists of two subscales- Baseline (study entry) endpoint (8 months) Behaviour and Worry. There are 28 items in the survey that the participant ranks from Never (0) to Almost Always (4). Higher scores indicate fear of hypoglycaemia. In the Behaviour subscale the lowest possible score in 0 and the highest possible score is 60. In the Worry subscale the lowest possible score is 0 and the highest is 72. Participants will complete this questionnaire at study entry and study end.

    Time frame: Baseline (study entry) endpoint (8 months)

  12. Change in Confidence of Managing Hypoglycaemia

    Measured using the Hypoglycaemic Confidence Scale- this is a 9 item scale. The participant rates each item from Not Confident at All to Very Confident. Participants will complete this questionnaire at study entry and study end. Higher scores mean more confidence. 'Not confident' at lower end of scale scored as 1 and 'very confident' at top of the scale scored as 4. Min score is 9 and max score is 36.

    Time frame: Baseline (study entry) endpoint (8 months)

  13. Hypoglycaemia Awareness

    Measured during each clamp study using the Edinburgh Hypoglycaemic Scale- this is a 17 item scale of symptoms of hypoglycaemia. The participant ranks on a scale from Not at all (1) to A Great Deal (7) whether they are experiencing each symptom at the time of the questionnaire being completed. Higher scores mean more hypoglycaemia symptoms. The lowest possible score is 0 and the highest possible score is 119.

    Time frame: Clamp 1 - study entry, clamp 2 - 8 months

  14. Trial Making Test

    Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Delta score plateau 1 (5 mmol/L) to plateau 3 (2.5 mmol/L) compared between clamp studies. Participants are timed completing the test. Higher scores indicate a longer time to complete the test.

    Time frame: Clamp 1- study entry, clamp 2 - 8 months

  15. Digit Span Test

    Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in change in score from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L) compared between clamp studies. Lower scores mean more errors. Forwards- participant repeats the numbers as read. Backwards- the participant repeats the numbers backwards.

    Time frame: Clamp 1- study entry, clamp 2 - 8 months

  16. Digit Symbol Substitution Test

    Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in score between plateau 1 (5.0 mmol/L) and plateau 3 (2.5 mmol/L) compared between clamp studies. Given 90 seconds to complete as many items as possible. Higher scores mean more items completed in the allotted time.

    Time frame: Clamp 1- study entry, clamp 2 - 8 months

  17. Four Choice Reaction Time Test

    Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in score between plateau 1 (5.0mmol/L) and plateau 3 (2.5 mmol/L) compared between clamp studies. Higher scores mean more time taken to complete the task.

    Time frame: Clamp 1- study entry, clamp 2 - 8 months

07

Results

Posted Dec 17, 2025

Participant flow

Participant flow — Overall Study
MilestoneGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Started811
Completed511
Not completed30

Outcome measures

PrimaryThe Change in Plasma Glucagon Levels (Pmol/L) Measured During Normoglycaemic and Hypoglycaemia

The delta glucagon concentration (pmol/L) from plateau 1 (normoglycaemia- 5.0 mmol/L) to plateau 3 (hypoglycaemia- 2.5 mmol/L). The physiological response in health would be for an increase in glucagon secretion from normo- to hypoglycaemia.

Time frame:
Clamp 1 at baseline and clamp 2 at 8 months
Reported as:
Median · pmol/L
The Change in Plasma Glucagon Levels (Pmol/L) Measured During Normoglycaemic and Hypoglycaemia
pmol/LGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Delta Clamp 1 (P3-P1)1.34 (0.46 to 4.52)1.68 (0.96 to 3.35)
Delta Clamp 2 (P3-P1)2.26 (0.52 to 3.64)0.31 (0.00 to 1.53)
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = >0.99
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.64
SecondaryTime in Glycaemic Range (3.9-10mmol/L)

Percentage time spent in target glycaemic range.

Time frame:
Baseline (study entry), midpoint at 4 months and endpoint at 8 months
Reported as:
Mean · Percentage
Time in Glycaemic Range (3.9-10mmol/L)
PercentageGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline51.46 ± 13.6353.55 ± 14.48
Midpoint44.26 ± 11.578.01 ± 6.32
Endpoint39.64 ± 20.1576.85 ± 9.61
Statistical analysis
  • Group 1 - Standard Care vs Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · ANOVA · p = 0.37
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · ANOVA · p = <0.0001
SecondaryTime Spent Below the Target Glycaemic Range (<3.9mmol/L)

Percentage of time spent below the target glycaemic range

Time frame:
Baseline (study entry), midpoint at 4 months and endpoint at 8 months
Reported as:
Mean · Percentage
Time Spent Below the Target Glycaemic Range (<3.9mmol/L)
PercentageGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline1.02 ± 0.622.13 ± 3.17
Midpoint2.25 ± 3.500.94 ± 0.55
Endpoint2.18 ± 3.850.74 ± 0.57
Statistical analysis
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · ANOVA · p = 0.20
  • Group 1 - Standard Care · ANOVA · p = 0.95
SecondaryTime Spent Above the Target Glycaemic Range (>10mmol/L)

Percentage of time spent above the target glycaemic range

Time frame:
Baseline (study entry), midpoint at 4 months and endpoint at 8 months
Reported as:
Mean · Percentage
Time Spent Above the Target Glycaemic Range (>10mmol/L)
PercentageGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline21.94 ± 13.9333.64 ± 12.42
Midpoint21.67 ± 13.5518.93 ± 4.66
Endpoint23.42 ± 17.2319.06 ± 5.87
Statistical analysis
  • Group 1 - Standard Care · ANOVA · p = 0.58
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · ANOVA · p = 0.01
SecondaryThe Change in Plasma Cortisol (ng/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

Delta cortisol from P1 (5.0 mmol/L) to P3 (2.5 mmol/L)

Time frame:
Clamp 1 at baseline and clamp 2 at 8 months
Reported as:
Mean · ng/mL
The Change in Plasma Cortisol (ng/mL) Levels Measured During Normoglycaemic and Hypoglycaemia
ng/mLGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Delta P3-P1 Clamp 1146 ± 12672.52 ± 91.48
Delta P3-P1 Clamp 2195.2 ± 115.911.31 ± 37.14
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.13
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.01
SecondaryThe Change in Plasma Adrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

Delta adrenaline from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L)

Time frame:
Clamp 1 at baseline and clamp 2 at 8 months
Reported as:
Median · Delta pg/mL
The Change in Plasma Adrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia
Delta pg/mLGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Clamp 1260 (78.5 to 499)187 (27.25 to 658.5)
Clamp 2413 (267.5 to 524.5)252.5 (172.8 to 696.5)
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.63
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.36
SecondaryThe Change in Plasma Noradrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia

The change in noradrenaline concentration from plateau 1 (5 mmol/L) to plateau 3 (2.5 mmol/L).

Time frame:
Clamp 1 at baseline and clamp 2 at 8 months
Reported as:
Median · pg/mL
The Change in Plasma Noradrenaline (pg/mL) Levels Measured During Normoglycaemic and Hypoglycaemia
pg/mLGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Delta noradrenaline (P3-P1) Clamp 149 (-132 to 225)-10.56 (-50.25 to 38.75)
Delta noradrenaline (P3-P1) Clamp 2-43 (-133 to 56)90.5 (3.75 to 172.3)
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.44
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.02
SecondaryEndogenous Glucose Production

The change in the glucose rate of appearance from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L)

Time frame:
Clamp 1 at baseline and clamp 2 at 8 months
Reported as:
Mean · mg/kg/minute
Endogenous Glucose Production
mg/kg/minuteGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Delta glucose rate of appearance P3-P1 Clamp 1-0.16 ± 0.21-0.12 ± 0.16
Delta glucose rate of appearance P3-P1 Clamp 2-0.22 ± 0.16-0.8 ± 0.16
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.38
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.88
SecondaryHbA1c

Delta HbA1c from baseline to study endpoint.

Time frame:
Baseline (study entry) endpoint (8 months)
Reported as:
Median · mmol/mol
HbA1c
mmol/molGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
HbA1c0 (-4.5 to 4)-12 (-18 to -4)
Statistical analysis
  • Group 1 - Standard Care vs Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.0094
SecondaryChange in Quality of Life at Trial Entry and End.

Measured using the EQ5D-5L- -VAS. Number on scale of 0-100 to assess wellbeing on that day. 100 being the most well.

Time frame:
Baseline (study entry) endpoint (8 months)
Reported as:
Mean · Number
Change in Quality of Life at Trial Entry and End.
NumberGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline81 ± 6.5279.36 ± 12.33
Endpoint82 ± 11.5180.27 ± 9.96
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = >0.99
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.82
SecondaryChange in Emotional Distress Related to Diabetes at Trial Entry and End.

Diabetes Distress Scale (DDS-1)- a 28-item self-reporting scale. Each item can be scored from 1 (not a problem) to 6 (a very serious problem). This questionnaire will be completed at study entry and study end. Data presented is the DDS total score.

Time frame:
Baseline (study entry) endpoint (8 months)
Reported as:
Mean · Numerical score
Change in Emotional Distress Related to Diabetes at Trial Entry and End.
Numerical scoreGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline2.18 ± 0.642.2 ± 1.15
Endpoint1.96 ± 0.661.58 ± 0.49
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.13
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.03
SecondaryChange in Fear of Hypoglycaemic

Measured using the Hypoglycaemia Fear Survey (HFS)- this survey consists of two subscales- Baseline (study entry) endpoint (8 months) Behaviour and Worry. There are 28 items in the survey that the participant ranks from Never (0) to Almost Always (4). Higher scores indicate fear of hypoglycaemia. In the Behaviour subscale the lowest possible score in 0 and the highest possible score is 60. In the Worry subscale the lowest possible score is 0 and the highest is 72. Participants will complete this questionnaire at study entry and study end.

Time frame:
Baseline (study entry) endpoint (8 months)
Reported as:
Mean · Numerical score
Change in Fear of Hypoglycaemic
Numerical scoreGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Behaviour Scale Baseline22 ± 4.2420.55 ± 4.03
Behaviour Scale Endpoint19.2 ± 8.1118.82 ± 4.79
Worry scale Baseline24 ± 9.3424.25 ± 15.85
Worry Scale Endpoint21.4 ± 15.3912.88 ± 9.78
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.25
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.63
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.35
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.09
SecondaryChange in Confidence of Managing Hypoglycaemia

Measured using the Hypoglycaemic Confidence Scale- this is a 9 item scale. The participant rates each item from Not Confident at All to Very Confident. Participants will complete this questionnaire at study entry and study end. Higher scores mean more confidence. 'Not confident' at lower end of scale scored as 1 and 'very confident' at top of the scale scored as 4. Min score is 9 and max score is 36.

Time frame:
Baseline (study entry) endpoint (8 months)
Reported as:
Mean · Numerical score
Change in Confidence of Managing Hypoglycaemia
Numerical scoreGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Baseline27.2 ± 5.1727.64 ± 7.63
Endpoint29.2 ± 5.3131.27 ± 3.9
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.25
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.09
SecondaryHypoglycaemia Awareness

Measured during each clamp study using the Edinburgh Hypoglycaemic Scale- this is a 17 item scale of symptoms of hypoglycaemia. The participant ranks on a scale from Not at all (1) to A Great Deal (7) whether they are experiencing each symptom at the time of the questionnaire being completed. Higher scores mean more hypoglycaemia symptoms. The lowest possible score is 0 and the highest possible score is 119.

Time frame:
Clamp 1 - study entry, clamp 2 - 8 months
Reported as:
Median · Numerical score
Hypoglycaemia Awareness
Numerical scoreGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Clamp 1 Plateau 124 (22.5 to 31.5)27 (18 to 32)
Clamp 1 Plateau 235 (29.5 to 60.5)25 (19 to 50)
Clamp 1 Plateau 339.64 (30.5 to 62.5)34 (24 to 64)
Clamp 2 Plateau 134 (23.5 to 36)28 (22 to 36)
Clamp 2 Plateau 234 (27 to 64.5)29 (24 to 60)
Clamp 2 Plateau 346 (29.5 to 71)47 (26 to 76)
Statistical analysis
  • Group 1 - Standard Care · ANOVA · p = 0.77 (Column factor p-value.)
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · ANOVA · p = 0.37
SecondaryTrial Making Test

Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Delta score plateau 1 (5 mmol/L) to plateau 3 (2.5 mmol/L) compared between clamp studies. Participants are timed completing the test. Higher scores indicate a longer time to complete the test.

Time frame:
Clamp 1- study entry, clamp 2 - 8 months
Reported as:
Median · Minutes
Trial Making Test
MinutesGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Trail making A delta clamp 1-3.05 (-4.55 to 0.4)0.00 (-12.0 to 1.50)
Trail making A delta clamp 2-2.6 (-4.55 to 0.05)-1.9 (-7.2 to 2.4)
Trail making B delta clamp 111.5 (-10.35 to 22.8)-7.8 (-10.0 to 1.0)
Trail making B delta clamp 20.7 (-2.98 to 5.5)-5.6 (-23.9 to -0.9)
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.88
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.69
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.41
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.49
SecondaryDigit Span Test

Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in change in score from plateau 1 (5mmol/L) to plateau 3 (2.5 mmol/L) compared between clamp studies. Lower scores mean more errors. Forwards- participant repeats the numbers as read. Backwards- the participant repeats the numbers backwards.

Time frame:
Clamp 1- study entry, clamp 2 - 8 months
Reported as:
Median · Correct responses
Digit Span Test
Correct responsesGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Digit span forwards clamp1-1 (-2 to 0)-1 (-1 to 1)
Digit span forwards clamp 20 (-1.5 to 1.5)0 (-1 to 0)
Digit span backwards clamp 10 (-1 to 0)0 (-1 to 0)
Digit span backwards clamp 20 (-1 to 2)0 (0 to 1)
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.5
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.5
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.53
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · Wilcoxon (Mann-Whitney) · p = 0.4
SecondaryDigit Symbol Substitution Test

Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in score between plateau 1 (5.0 mmol/L) and plateau 3 (2.5 mmol/L) compared between clamp studies. Given 90 seconds to complete as many items as possible. Higher scores mean more items completed in the allotted time.

Time frame:
Clamp 1- study entry, clamp 2 - 8 months
Reported as:
Mean · Correct responses
Digit Symbol Substitution Test
Correct responsesGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Delta score clamp 1-4.4 ± 5.40.82 ± 6.56
Delta score clamp 2-6.6 ± 13.7-4.0 ± 7.1
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.88
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.06
SecondaryFour Choice Reaction Time Test

Measured during each plateau in a stepped hypoglycaemic clamp study at study entry and study end. Difference in score between plateau 1 (5.0mmol/L) and plateau 3 (2.5 mmol/L) compared between clamp studies. Higher scores mean more time taken to complete the task.

Time frame:
Clamp 1- study entry, clamp 2 - 8 months
Reported as:
Mean · Time (ms)
Four Choice Reaction Time Test
Time (ms)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Clamp 115.4 ± 7.438.45 ± 63.21
Clamp 252.9 ± 20.4357.78 ± 60.63
Statistical analysis
  • Group 1 - Standard Care · Wilcoxon (Mann-Whitney) · p = 0.38
  • Group 2- Automated Insulin Delivery and Low Carbohydrate Diet · t-test, 2 sided · p = 0.27

Adverse events

Collected over From recruitment of participant to study completion (8 months per participants).. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Group 1 - Standard Care0/5 (0%)0/5 (0%)0/5 (0%)
Group 2- Automated Insulin Delivery and Low Carbohydrate Diet0/11 (0%)1/11 (9.1%)0/11 (0%)
Most frequent serious events
Most frequent serious events
EventGroup 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate Diet
Proliferative retinopathyEye disorders0/51/11

Baseline characteristics

Age, Continuous
Age, Continuous(Years)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Mean35.9 ± 11.342.9 ± 9.539.95 ± 10.63
Sex/Gender, Customized
Sex/Gender, Customized(participants)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Female6410
Race and Ethnicity Not Collected
Race and Ethnicity Not Collected(Participants)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Count of participants——0
Region of Enrollment
Region of Enrollment(participants)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
United Kingdom81119
Age Diagnosed (Years)
Age Diagnosed (Years)(Years)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Median7 (3 to 32)20 (7 to 31)16.5 (4.75 to 31.25)
Time since diagnosis (Years)
Time since diagnosis (Years)(Years)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Median19.2 (14 to 28.1)25.5 (11 to 32)24.67 (12.5 to 31.29)
HbA1c
HbA1c(mmol/mol)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Median63 (63 to 64.8)61 (57 to 68)63 (58 to 65)
Weight
Weight(Kg)Group 1 - Standard CareGroup 2- Automated Insulin Delivery and Low Carbohydrate DietTotal
Mean84.5 ± 11.977.33 ± 7.880.35 ± 10.14

8 further baseline measures are reported on the registry.

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Study locations

1 site
  • Edinburgh Royal Infirmary/University of Edinburgh
    Edinburgh, United Kingdom
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References and documents

Publications

  • Baxter F, Baillie N, Forbes S. Study protocol: a randomised controlled proof-of-concept real-world study - does maximising time in range using hybrid closed loop insulin delivery and a low carbohydrate diet restore the glucagon response to hypoglycaemia in adults with type 1 diabetes? BMJ Open. 2022 Dec 20;12(12):e054958. doi: 10.1136/bmjopen-2021-054958. PubMed 36600427 ↗

Study documents

  • Protocol and statistical analysis plan · Sep 28, 2022

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: No

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jan 28, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT04614168
Lead sponsor
University of Edinburgh
Collaborators
NHS Lothian, The Leona M. and Harry B. Helmsley Charitable Trust, Tandem Diabetes Care, Inc., DexCom, Inc.
Responsible party
Sponsor
First posted
Nov 3, 2020
Start date
Jul 26, 2021
Primary completion
Sep 22, 2023
Completion
Dec 26, 2025
Results posted
Dec 17, 2025
Last update
Jan 28, 2026

Study contacts

Shareen Forbes, MBChB, PhD
principal investigator · University of Edinburgh

Oversight

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

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