Recruiting

Empiric vs. Selective

Sponsor:

Icahn School of Medicine at Mount Sinai

Code:

NCT07225764

Conditions

Kidney Stones

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Chlorthalidone

Low oxalate diet

Study Details

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.

Conditions

Kidney Stones

Study ID

NCT07225764

Start date

Oct 23, 2025

Status verified date

Aug, 2026

Completion date

Dec 31, 2027

Anticipated

Primary completion date

Dec 31, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

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

Study Design

Enrollment

80 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: 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.

active comparator: 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.

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.

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.

Primary outcome measure

  • Changes in super saturation of calcium oxalate [ Time Frame: 4-6 weeks ]

Central Contacts and Locations

Central contacts

Blair Gallante, MPH

631-991-1159blair.gallante@mountsinai.org

Mantu Gupta, MD

212-241-1272mantu.gupta@mountsinai.org

Locations

Mount Sinai West

Recruiting

New York, New York, United States, 10019

Contacts

Mantu Gupta, MD

212-241-1272mantu.gupta@mountsinai.org

Blair Gallante, MPH

631-991-1159blair.gallante@mountsinai.org

Principal Investigator:

Mantu Gupta

More Information

Sponsor

Icahn School of Medicine at Mount Sinai

Last update posted

Aug 14, 2026

Last verified

Aug, 2026

Keywords

  • kidney stones
  • calcium oxalate
  • nephrolithiasis

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Icahn School of Medicine at Mount Sinai on 2026-08-14.