Observational Approach Versus Surgical Intervention for Stones

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:

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

Inclusion criteria

• Individuals age 6 or older
• Diagnosis of kidney stone disease (nephrolithiasis)
• 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.
• Informed consent and if appropriate, child assent.
• Willingness to be randomized to surgery or observation Note: subjects otherwise eligible who decline randomization may be enrolled in a parallel observational cohort.
• Fluent in English or Spanish
• Willingness to be audio- and/or video- recorded during interviews

Exclusion criteria

• Untreated hydronephrosis or caliectasis
• Pain (e.g., renal colic, abdominal pain) or gross hematuria attributed to kidney stones.
• 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).
• Stone in the renal pelvis, ureter, bladder or urethra
• Pregnant females
• Solitary kidney, transplant kidney, urinary diversion, medullary sponge kidney
• Anatomic abnormality of the kidney (e.g., horseshoe kidney)
• Parents/guardians or subjects who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures