RecruitingPhase 4NCT07225764

CaOx Stone Prevention

Empiric vs Selective Medical Therapy for Calcium Oxalate Stone Prevention: A Randomized Controlled Trial

Sponsor

Icahn School of Medicine at Mount Sinai

Enrollment

80 participants

Start Date

Oct 23, 2025

Study Type

INTERVENTIONAL

Conditions

Kidney Stones

Summary

This single-center randomized controlled trial at Mount Sinai West will enroll 80 patients undergoing percutaneous nephrolithotomy for calcium oxalate stones. Participants will be randomized to receive either empiric therapy or selective therapy guided by 24-hour urine evaluation. The primary outcome is change in calcium oxalate supersaturation at 4 weeks, aiming to determine whether empiric therapy can provide outcomes comparable to selective therapy while simplifying access to prevention.

Eligibility

Min Age: 18 Years

Inclusion Criteria7

Adult age of 18 years
Diagnosed with kidney stones and scheduled for PCNL.
Calcium Oxalate Stone Former
Pre-operative CT-scan within 90 days of surgery and stone density with \> 1000 Hounsfield units
Non-pregnant or breastfeeding
Able and willing to provide informed consent.
Pre-operative eGFR greater than 70 mL/min/1.73 m² -Negative pre-operative urine culture

Exclusion Criteria6

Documented history of gastric or intestinal bypass, liver disease, history of gastrointestinal malabsorptive disease (Crohn's disease, ulcerative colitis, and short-gut syndrome)
Hyperparathyroidism -Renal tubular acidosis
Active kidney stone prevention treatment (use of thiazides, alkaline therapy, or low oxalate diet) at the time of surgery
History of hypokalemia or baseline hypotension
Allergy to medications used in trial or sulfa-containing medications
Patient prescribed thiazide, loop diuretics, carbonic anhydrase inhibitors, xanthine oxidase inhibitors, active Vitamin D, bisphosphonates, denosumab, glucocorticoids, or potassium supplementation

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Interventions

DRUGChlorthalidone

Chlorthalidone 25 mg orally once daily is used to reduce urinary calcium excretion and prevent recurrent calcium-containing kidney stones. In this study, it is prescribed either based on stone composition (empiric group) or guided by 24-hour urine results (selective group) for participants meeting criteria for hypercalciuria or calcium oxalate dihydrate stones.

BEHAVIORALLow oxalate diet

Participants receive counseling to follow a low oxalate diet, limiting high oxalate foods (\>50 mg/100 g) and restricting moderate oxalate foods (\<50 mg/100 g) to a single four-ounce serving per day. The diet is prescribed either based on stone composition (empiric group) or guided by 24-hour urine results (selective group) for participants with idiopathic hyperoxaluria or calcium oxalate monohydrate stones.