Effect of a High Citrate Beverage on Urine Chemistry in Urinary Stone Disease

This study will investigate the effect of a patented high citrate beverage on urine chemistry in patients with urinary stone disease (USD). It is a minimal risk study of an over-the-counter beverage called Moonstone, which is commercially available. This study is considered preparatory for the RO-1 and is not intended to produce a definitive outcome regarding kidney stones.

Study Overview

• Status: Completed
• Conditions: Urinary Stone
• Intervention / Treatment: Other: Water; Dietary supplement: Moonstone

• Study Type: Interventional
• Enrollment (Actual): 6
• Phase: Early Phase 1

Contacts and Locations

Study Locations

• United States
  • New York
    • New York, New York, United States, 10016
      • NYU Langone Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

The study will enroll patients with calcium, cystine and uric acid stone composition. Patients will be at least 18 years of age, with no upper limit of age. Patients will sign an informed consent form (ICF). We will seek participants who have experienced any USD events including renal colic with spontaneous stone passage, emergency room visits, or urological interventions, in the previous 5 years in order to encourage enrollment and adherence to the protocol. We will include all racial and ethnic groups, and both men and women. Besides stone composition, standard demographic data including gender, age, and body mass index will be collected.

Patients who are taking alkalinizing medications for prevention of USD including KCit, potassium bicarbonate, sodium citrate and sodium bicarbonate will be eligible for participation in the study. The patient's usual dose, however, will be discontinued for the 2 weeks which make up the two study periods. This maneuver will not be an important risk for stones for several reasons: 1) the period off alkali altogether will be one week; 2) the one week of Moonstone will offer a significant amount of alkali, likely as much or more than the patients' usual prescription doses; 3) participants will continue to adhere to fluid intake and dietary prescriptions.

These data are intended to be included in an RO-1 resubmission due November 5. We will therefore aspire to include 10 patients with calcium stones, 3 patients with cystine stones and 3 patients with uric acid stones.

Exclusion Criteria:

Investigators will exclude patients taking thiazides (indapamide, hydrochlorothiazide, and chlorthalidone). Our reasoning is that most calcium stone patients are not taking thiazides and such patients may be total body potassium-depleted (not necessarily reflected by serum potassium. Potassium depletion reduces citrate excretion (through effects on intracellular pH in the proximal tubule) so that patients taking thiazides could start with lower urine citrate excretion and have less of an increment in the Moonstone periods. The order of the periods might affect the magnitude of urine chemistry changes in those two periods.

Patients with chronic kidney disease tend to have reduced urinary citrate excretion due to mild metabolic acidosis. We will therefore exclude patients with estimated glomerular filtration rates (eGFRs) less than 60 ml/min/1.73 m2 calculated by the CKD-EPI equation. eGFRs will have been measured in the preceding year at a time when urinary tract obstruction due to USD was not present. We will also exclude women who are pregnant or nursing and people with any medical, psychiatric, debilitating disease/disorder, or social condition that in the judgment of the investigator would interfere with or serve as a contraindication to adherence to the study protocol or ability to give informed consent, or affect the overall prognosis of the patient.

The study will also exclude patients with a previous history of gastrointestinal intolerance, or any other intolerance of alkalinizing preparations. The proportion of USD patients who do not tolerate KCit is not clear. The Cochrane review on this topic states that there are adverse events reported with citrate therapy, but the effect was not statistically significant, in part because of incomplete reporting. Based on our experience, we usually cite this problem to affect about 10% of stone formers, with older people more frequently affected. We therefore do not think this exclusion criterion will have a sizable effect on enrollment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Study period "Water"; Participants will take in 1L of tap water per day plus ad lib, self-selected fluids.	Other: Water; Participants will take in 1L of tap water per day plus ad lib, self-selected fluids. Participants will follow their own self-chosen ad lib diets and complete a diet diary (Appendix) for days 6 and 7 in the first study period. On day 7, a 24-hour urine collection will be performed, and a 50-ml aliquot of urine will be sent to Litholink (Chicago, IL) via FedEx for analysis. Participants will then continue to the second study period and will use the diet diary completed in the first study period on days 6 and 7 to reproduce the identical diets for days 6 and 7 of the subsequent collection period.
Experimental: Study period "Moonstone"; Participants will take one packet of Moonstone powder reconstituted in 500 ml water, twice a day, to total 1 L per day (66 meq of potential alkali/day) plus ad lib fluids. Moonstone packets will be supplied by Dr. Arnie's, Inc.	Dietary supplement: Moonstone; Participants will take one packet of Moonstone powder reconstituted in 500 ml water, twice a day, to total 1 L per day (66 meq of potential alkali/day) plus ad lib fluids. Moonstone packets will be supplied by Dr. Arnie's, Inc. Participants will follow their own self-chosen ad lib diets and complete a diet diary (Appendix) for days 6 and 7 in the first study period. On day 7, a 24-hour urine collection will be performed, and a 50-ml aliquot of urine will be sent to Litholink (Chicago, IL) via FedEx for analysis. Participants will then continue to the second study period and will use the diet diary completed in the first study period on days 6 and 7 to reproduce the identical diets for days 6 and 7 of the subsequent collection period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urine citrate excretion	In calcium stone formers, the effect of Moonstone on urine citrate excretion will be compared to that of water in a non-inferiority analysis.	24 hours
24-hour urine volume	The effects of Moonstone on 24-hour urine volume, calcium excretion and SS will be compared.	24 hours
24-hour urine pH	The effect of Moonstone on 24-hour urine pH will be compared to that of water in a non-inferiority analysis in both cystine and uric acid stone formers	24 hours
Increase in 24-hour urine citrate excretion	A secondary outcome is an increase in 24-hour urine citrate excretion after Moonstone, compared with a period of water, in calcium stone-forming individuals.	24 hours

Collaborators and Investigators

• Sponsor: NYU Langone Health

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2020
• Primary Completion (Actual): December 14, 2020
• Study Completion (Actual): December 14, 2020

Study Registration Dates

• First Submitted: January 4, 2021
• First Submitted That Met QC Criteria: January 4, 2021
• First Posted (Actual): January 6, 2021

Study Record Updates

• Last Update Posted (Actual): January 6, 2021
• Last Update Submitted That Met QC Criteria: January 4, 2021
• Last Verified: January 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urologic Diseases; Pathological Conditions, Anatomical; Calculi; Urinary Calculi; Urolithiasis
• Other Study ID Numbers: 20-01153

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: The de-identified participant data from the final research dataset used in the published manuscript will be shared upon reasonable request beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research provided the investigator who proposes to use the data executes a data use agreement with NYU Langone Health. Requests may be directed to the PI. The protocol and statistical analysis plan will be made available on Clinicaltrials.gov only as required by federal regulation or as a condition of awards and agreements supporting the research.
• IPD Sharing Time Frame: beginning 9 months and ending 36 months following article publication
• IPD Sharing Access Criteria: Requests may be directed to the PI.
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No