CaOx Stone Prevention

Mount Sinai Health System

Status and phase: Enrolling; Phase 4

Conditions: Kidney Stones

Treatments: Behavioral: Low oxalate diet; Drug: Chlorthalidone

Study type: Interventional

Funder types: Other

Identifiers

NCT07225764

STUDY-25-00784

Details and patient eligibility

About

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.

Full description

This is a single-center, randomized controlled trial evaluating the effectiveness of empiric versus selective medical therapy for the prevention of calcium oxalate kidney stones. The study will enroll 80 patients at Mount Sinai West undergoing percutaneous nephrolithotomy (PCNL) for predominantly calcium oxalate stones. Participants will be randomized postoperatively to receive either empiric therapy (based on stone composition and urinalysis) or selective therapy (based on 24-hour urine metabolic evaluation). The primary endpoint is the change in calcium oxalate supersaturation (ssCaOx) at 4 weeks post-treatment. The study is designed to determine whether an empiric approach can achieve comparable outcomes to selective therapy while simplifying access to preventive treatment.

Enrollment: 80 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 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 criteria

• 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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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80 participants in 2 patient groups

Empiric Therapy

Experimental group

Description:

Patients randomized to the empiric group will receive treatment based on the pH on urinalysis and stone composition. Patients with greater than 50% calcium oxalate monohydrate (COM) stone composition will be counseled on a low oxalate diet by a medical provider. Patients with greater than 50% calcium oxalate dihydrate (COD) stone composition will be prescribed 25 mg of chlorthalidone once a day. In the rare event the stone composition is 50% COM and 50% COD, then those patients will receive both low oxalate diet counseling and a prescription for chlorthalidone.

Treatment:

Drug: Chlorthalidone

Behavioral: Low oxalate diet

Selective Therapy

Active Comparator group

Description:

Patients randomized to the selective group will undergo medical therapy based on the American Urological Association (AUA) guidelines from the 24-hour urine collection results. Patients with idiopathic hyperoxaluria (\> 40mg/day) will receive a low oxalate diet and receive the same dietary counseling, handout, and questionnaire as the empiric group. Patients with idiopathic hypercalciuria (\> 250mg in men, \>200mg in women) will be prescribed 25mg of chlorthalidone once a day.

Treatment:

Drug: Chlorthalidone

Behavioral: Low oxalate diet