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RecruitingNCT07718802OASISUpdated Sep 3, 2026

Observational Approach Versus Surgical Intervention for Stones

An interventional study of Surgery and Observation in Nephrolithiasis and Kidney Stone, sponsored by Children's Hospital of Philadelphia. Recruiting at 2 sites in United States. Open to participants aged 6 Years and older. Per ClinicalTrials.gov, last updated 2026-09-03.

Sponsored by Children's Hospital of Philadelphia · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
1,658
Allocation
Randomized
Ages
6 Years and older
Sex
All
01

Study summary

The aims of the Observational Approach versus Surgical Intervention for Asymptomatic Stone (OASIS) trial are: 1) to determine whether observation compared to upfront surgery results in less healthcare-related life disruption due to kidney stones among children and adults with asymptomatic kidney stones; 2) to identify the groups benefiting the most from each strategy; and 3) to determine the preferences and values informing the choice between observation and upfront surgery.

Read the detailed description

A critical barrier to improving the health of the nearly 40 million Americans with kidney stone disease is the weak evidence base supporting the management of individuals with asymptomatic kidney stones. The proposed Observational Approach versus Surgical Intervention for Asymptomatic Stone (OASIS) randomized clinical trial answers the research question of whether observation or upfront surgery results in less life disruption from asymptomatic kidney stones for children and adults. The management options for patients with asymptomatic stones are 1) observation or 2) upfront surgical treatment, both of which are considered safe, part of usual care, widely accessible, and covered by insurance.

OASIS responds to the charge for well-designed Randomized Controlled Trials (RCT) from the Agency for Healthcare Research and Quality (AHRQ) systematic review on kidney stone disease management and ensures patient centeredness by examining outcomes that patients have identified as meaningful.

Intervention

Randomization to either:

  1. Observation is the surveillance of asymptomatic stones with periodic CT, ultrasound, or x-ray, and clinic visits.
  2. Upfront surgery is the planned removal of asymptomatic stones and includes ureteroscopy (URS) and shockwave lithotripsy (SWL), which are routinely used in standard clinical care.

Observational Cohort (Non-Randomized Cohort):

Up to 300 eligible subjects who are willing to consent to data collection but refuse randomization will be enrolled and followed for two years.

Study Design OASIS is a pragmatic randomized controlled superiority trial conducted at approximately 30 sites that participate in Patient Centered Outcomes Research Network (PCORnet). The trial will include an additional observational cohort for eligible subjects who decline randomization.

02

Conditions studied

  • Nephrolithiasis
  • Kidney Stone

Keywords

  • kidney stones
  • kidney
  • nephrolithiasis
  • Comparative Effectiveness
  • Patient Reported Outcomes
03

Who can participate

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

Inclusion criteria

  1. Individuals age 6 or older
  2. Diagnosis of kidney stone disease (nephrolithiasis)
  3. Asymptomatic, non-obstructive kidney stones measuring 4 to 10 mm (inclusive)

    • Asymptomatic is defined as the absence of abdominal pain, flank pain, gross hematuria, and nausea and/or vomiting in the last 3 months that in the judgement of the site PI could be attributable to kidney stones.
    • Non-obstructive is defined as a stone in a renal calyx or stones in multiple renal calyces on CT, ultrasound, and/or x-ray obtained within 6 months of screening.
  4. Informed consent and if appropriate, child assent.
  5. Willingness to be randomized to surgery or observation Note: subjects otherwise eligible who decline randomization may be enrolled in a parallel observational cohort.
  6. Fluent in English or Spanish
  7. Willingness to be audio- and/or video- recorded during interviews

Exclusion criteria

Exclusion Criteria:

  1. Untreated hydronephrosis or caliectasis
  2. Pain (e.g., renal colic, abdominal pain) or gross hematuria attributed to kidney stones.
  3. Recurrent symptomatic urinary tract infections (≥3 in 12 months or ≥2 in 6 months). A symptomatic urinary tract infection is defined as having at least one bladder or voiding symptom (e.g., frequency, urgency, dysuria) with bacteriuria (≥105 colony forming units/mL of no more than 2 urinary tract pathogens).
  4. Stone in the renal pelvis, ureter, bladder or urethra
  5. Pregnant females
  6. Solitary kidney, transplant kidney, urinary diversion, medullary sponge kidney
  7. Anatomic abnormality of the kidney (e.g., horseshoe kidney)
  8. Parents/guardians or subjects who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures
04

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
1,658 participants (estimated)

Study arms

  • Active comparator
    Non-Randomized (Observational)

    Procedure: Surgery · Other: Observation

  • Active comparator
    Randomized

    Procedure: Surgery · Other: Observation

Interventions

  • ProcedureSurgery

    Upfront surgery is the planned removal of asymptomatic stones and includes ureteroscopy and shockwave lithotripsy, which are routinely used in standard clinical care.

  • OtherObservation

    Observation is the surveillance of asymptomatic stones with periodic CT, ultrasound, or x-ray, and clinic visits.

05

What researchers measure

Primary outcomes

  1. Healthcare-related life disruption

    Composite of: Stone-specific emergency department (ED)/urgent care visits, stone-specific hospitalizations and surgery for stones for new symptoms (Shockwave Lithotripsy (SWL) and Ureteroscopy (URS)) as reported via Patient Centered Outcomes Research Network (PCORnet) Common Data Model (CDM) query and participant self-report on REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

Secondary outcomes

  1. Patient reported physical and emotional health (Pain Interference)

    Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference (PI) is a standardized, self-reported assessment tool developed by the National Institutes of Health (NIH). It measures how much pain hinders a person's physical, mental, social, and recreational activities, as well as their sleep and enjoyment of life. It uses a standardized T-score (average is 50; standard deviation is 10) to reflect the level of disruption. Higher numbers mean more pain interference (pain is having a greater negative impact on your daily life, making it harder to participate in work, social, and physical activities). The study team is using the validated versions for adults (18 years and older at time of consent), children (ages 8-17 years at time of consent), and parent-proxy versions for caregivers of children ages (6-7 years at time of consent). This information will be captured via patient report in REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

  2. Patient reported physical and emotional health (Anxiety)

    Patient-Reported Outcomes Measurement Information System (PROMIS) Anxiety is a standardized, self-reported assessment tool developed by the National Institutes of Health (NIH). It measures the severity of fear, worry, dread, hyperarousal, and physical stress symptoms over the past seven days on a 5-point scale (ranging from never to always). Raw scores are converted into a standardized T-score with an average of 50 and a standard deviation of 10. A higher T-score indicates a higher severity of anxiety. The study team is using validated versions for adults (18 years and older at time of consent), children (ages 8-17 years at time of consent), and parent-proxy versions for caregivers of children ages (6-7 years at time of consent). This information will be captured via patient report in REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

  3. Patient reported physical and emotional health (Stone Quality of Life)

    The Wisconsin Stone Quality of Life questionnaire (WISQOL) is a disease-specific health-related quality of life (HRQOL) instrument designed to assess the impact on patients of stones in the urinary tract. Each item is scored on a 5-point Likert scale, yielding a total raw score of 28 to 140. Higher scores reflect a better health-related quality of life. Raw scores are typically converted to a standardized 0-100 scale. This information will be captured via patient report on REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

  4. Stone passage

    Patient Reported Survey: Number of self-reported stone passages (A kidney stone episode is passing a stone that caused pain or other bothersome symptoms or having surgery to remove a stone.) This information will be captured via patient report on REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months. Reporting total after 2 years.

  5. Lost productivity (Missed School)

    Patient Reported Survey: Number of days the patient (for patients under 18 years old at time of consent) missed school due to kidney stones or kidney stone-related care (0 days, 1-2 days, 3-5 days, 6-10 days, more than 10 days) in the last 3 months. This information will be captured via patient report in REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

  6. Lost productivity (Caregiver Missed Work)

    Patient Reported Survey: Number of days the patient's caregiver(s) (for patients \<18 years old at time of consent) missed work due to kidney stones or kidney stone-related care (0 days, 1-2 days, 3-5 days, 6-10 days, more than 10 days) in the last 3 months. This information will be captured via patient report on REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

  7. Lost productivity (Patient Missed Work)

    Patient Reported Survey: Number of days the patient missed work (for patients 18 years and older at time of consent) due to kidney stones or kidney stone-related care (0 days, 1-2 days, 3-5 days, 6-10 days, More than 10 days) in the last 3 months. This information will be captured via patient report in REDCap.

    Time frame: Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

06

Study locations

1 of 2 sites recruiting
  • University of Minnesota
    Minneapolis, Minnesota 55454, United States
    Not yet recruiting
  • The Children's Hospital of Philadelphia
    Philadelphia, Pennsylvania 19104, United States
    • Gregory E Tasian, MD, MSc, MSCE · Principal investigator
    Recruiting
07

References and documents

Individual participant data

Plan to share: Undecided

No publications or documents are linked to this record.

08

Registry details

Key details

Study ID
NCT07718802
Lead sponsor
Children's Hospital of Philadelphia
Collaborators
Patient-Centered Outcomes Research Institute
Responsible party
Sponsor
First posted
Jul 22, 2026
Start date
Aug 17, 2026
Primary completion
May 31, 2031 (estimated)
Completion
Oct 1, 2032 (estimated)
Last update
Sep 3, 2026

Study contacts

Rebecca D McCune, BS, MS
Contact
mccuner@chop.edu
267-909-6030
Brian J Augelli, BS
Contact
augellib@chop.edu
609-504-4908
Gregory E Tasian, MD, MSc, MSCE
principal investigator · Children's Hospital of Philadelphia

Oversight

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

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