Observational Approach Versus Surgical Intervention for Stones (OASIS)

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Nephrolithiasis; Kidney Stone
• Intervention / Treatment: Procedure: Surgery; Other: Observation

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.

• Study Type: Interventional
• Enrollment (Estimated): 1658
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Rebecca D McCune, BS, MS; Phone Number: 267-909-6030; Email: mccuner@chop.edu
• Study Contact Backup: Name: Brian J Augelli, BS; Phone Number: 609-504-4908; Email: augellib@chop.edu

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • The Children's Hospital of Philadelphia
      • Principal Investigator: Gregory E Tasian, MD, MSc, MSCE

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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:

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Non-Randomized (Observational)	Procedure: Surgery; Upfront surgery is the planned removal of asymptomatic stones and includes ureteroscopy and shockwave lithotripsy, which are routinely used in standard clinical care.; Other: Observation; Observation is the surveillance of asymptomatic stones with periodic CT, ultrasound, or x-ray, and clinic visits.
Active Comparator: Randomized	Procedure: Surgery; Upfront surgery is the planned removal of asymptomatic stones and includes ureteroscopy and shockwave lithotripsy, which are routinely used in standard clinical care.; Other: Observation; Observation is the surveillance of asymptomatic stones with periodic CT, ultrasound, or x-ray, and clinic visits.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Every 3 months (+/- 14 days) from date of consent (observational cohort) or randomization (randomized cohort) until 24 months.

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Children's Hospital of Philadelphia
• Collaborators: Patient-Centered Outcomes Research Institute
• Investigators: Principal Investigator: Gregory E Tasian, MD, MSc, MSCE, Children's Hospital of Philadelphia

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): May 31, 2031
• Study Completion (Estimated): October 1, 2032

Study Registration Dates

• First Submitted: July 16, 2026
• First Submitted That Met QC Criteria: July 16, 2026
• First Posted (Actual): July 22, 2026

Study Record Updates

• Last Update Posted (Actual): July 22, 2026
• Last Update Submitted That Met QC Criteria: July 16, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: kidney; kidney stones; nephrolithiasis; Patient Reported Outcomes; Comparative Effectiveness
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urolithiasis; Urinary Calculi; Pathological Conditions, Signs and Symptoms; Kidney Calculi; Nephrolithiasis; Investigative Techniques; Methods; Observation; Surgical Procedures, Operative
• Other Study ID Numbers: 26-024242; BPS-2025C1-44653 (Other Identifier: Patient-Centered Outcomes Research Institute)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No