CaOx Stone Prevention

NCT ID: NCT07225764

Last Updated: 2025-11-10

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: PHASE4
• Total Enrollment: 80 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-10-23
• Study Completion Date: 2027-06-30

Brief 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.

Detailed 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.

Conditions

Kidney Stones

Keywords

kidney stones; calcium oxalate; nephrolithiasis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Empiric Therapy

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.

Group Type: EXPERIMENTAL

Chlorthalidone

Intervention Type: DRUG

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.

Low oxalate diet

Intervention Type: BEHAVIORAL

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.

Selective Therapy

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.

Group Type: ACTIVE_COMPARATOR

Chlorthalidone

Intervention Type: DRUG

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.

Low oxalate diet

Intervention Type: BEHAVIORAL

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.

Interventions

Chlorthalidone

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.

Intervention Type: DRUG

Low 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.

Intervention Type: BEHAVIORAL

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Icahn School of Medicine at Mount Sinai

OTHER

Sponsor Role: lead

Responsible Party

Mantu Gupta

Chair of Urology, MSW and MSM Hospitals Professor, Icahn School of Medicine at Mount Sinai Director of Endourology, Mount Sinai Medical Center

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Mantu Gupta, MD

Role: PRINCIPAL_INVESTIGATOR

Mount Sinai West

Locations

Mount Sinai West

New York, New York, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Blair Gallante, MPH

Role: CONTACT

Phone: 631-991-1159

Email: blair.gallante@mountsinai.org

Mantu Gupta, MD

Role: CONTACT

Phone: 212-241-1272

Email: mantu.gupta@mountsinai.org

Facility Contacts

Mantu Gupta, MD

Role: primary

Blair Gallante, MPH

Role: backup

Other Identifiers

STUDY-25-00784

Identifier Type: -

Identifier Source: org_study_id