Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07225764

CaOx Stone Prevention

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.

Recruiting

Interested in participating?

Request Info

Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Chlorthalidone

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

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.

Primary outcomes

  1. Changes in super saturation of calcium oxalate

    Time frame: 4-6 weeks

    Change in urine calcium oxalate supersaturation from baseline to the final follow-up visit, measured via 24-hour urine collection. This is a marker that can be predictive of stone episodes, as recurrent stones may take years to develop.

Secondary outcomes

  1. Changes in urinary oxalate levels

    Time frame: 4-6 weeks

    Difference in 24-hour urinary oxalate excretion from baseline to the final follow-up visit, measured in mg/day, to assess the effect of dietary and pharmacologic interventions on oxalate levels.

  2. Changes in urinary calcium levels

    Time frame: 4-6 weeks

    Difference in 24-hour urinary calcium excretion from baseline to the final follow-up visit, measured in mg/day, to evaluate the effect of chlorthalidone and dietary interventions on urinary calcium levels.

  3. Chlorthalidone Adherence Survey (adapted from Brief Medication Questionnaire)

    Time frame: 4-6 weeks

    Participant-reported adherence to prescribed chlorthalidone therapy, assessed via a structured survey at the follow-up visit, to evaluate compliance with the study intervention.

    Response will be either 0=nonadherent or 1=adherent.

Study contacts

Contact information is provided by the study sponsor or research team.

Blair Gallante, MPH

CONTACT

[email protected]

631-991-1159

Mantu Gupta, MD

CONTACT

[email protected]

212-241-1272

Sponsors and collaborators

Lead sponsor

Icahn School of Medicine at Mount Sinai

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Nov 10, 2025
Registry last updated
Nov 10, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.