SGLT2i in Kidney Stones

January 8, 2026 updated by: University of Chicago

SGLT2i in Calcium Kidney Stones

This study is looking at whether empagliflozin, a medication typically used for diabetes and heart conditions, may affect factors that contribute to kidney stone formation. The research focuses on people who have had calcium-based kidney stones, i.e. calcium oxalate or calcium phosphate stones.

Previous studies in those without kidney stones found that empagliflozin increased urinary citrate levels without raising urine pH. The investigators are testing whether similar effects occur in people with a history of kidney stones.

Participants will take empagliflozin daily for 4 weeks. The investigators will collect 24-hour urine samples before and after treatment to measure various factors that influence stone formation, including citrate levels, pH, and calculated stone formation risk. The investigators will enroll 32 participants: 16 with a history of calcium oxalate stones and 16 with calcium phosphate stones.

Results from this study may inform future larger clinical trials investigating empagliflozin as a kidney stone prevention strategy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a single-center, prospective pilot study designed to evaluate the effects of the sodium-glucose co-transporter 2 inhibitor (SGLT2i), empagliflozin, on urinary risk factors in individuals with recurrent idiopathic calcium phosphate (CaP) or calcium oxalate (CaOx) kidney stones. Although empagliflozin is FDA-approved for other indications, it is being used off-label in our study to explore its potential for kidney stone prevention. The investigators' goal is to assess changes in urinary parameters relevant to stone formation, including citrate excretion, pH, and other metabolic markers.

Eligible participants will be adults aged 18 to 70 years with a documented history of CaP or CaOx kidney stones. Participants will be asked to stop certain medications and supplements prior to and during the study period if deemed safe by their primary care provider or nephrologist.

Each participant will complete two in-person study visits at the University of Chicago Clinical Research Center (CRC), a special research clinic, over approximately 4 weeks. They will also collect two 24-hour urine samples-one before starting the study drug and one at the end of the study. In addition, participants will take empagliflozin 10 mg once daily during the 4-week period and complete a brief phone or video check-in around the 2-week mark.

Laboratory tests and physical measurements will be performed during each visit. All urine samples will be analyzed by a central clinical laboratory (Litholink), and select samples will be stored for future analysis. Participants will be compensated for completing the study.

This pilot study is not intended to support a new drug indication or FDA labeling change. The findings will inform the design of a larger, hypothesis-driven study on the use of SGLT2 inhibitors in kidney stone prevention.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
32

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Calcium phosphate (CaP) stone participants:

  • Age 18-70

  • History of at least one calcium phosphate (hydroxyapatite) stone

    • Defined as at least 50% of stone material on most recent stone analysis

Calcium oxalate (CaOx) stone participants:

  • Age 18-70

  • History of at least one calcium oxalate stone

    • Defined as at least 50% of stone material on most recent stone analysis.

Other inclusion criteria considerations: The investigators will study balanced numbers of male and females. Prior studies did not have balanced representation of male and female sexes. In prior studies, less than 40% were female, or sex data is not presented. Study of both male and female sex is crucial with kidney stones and therapies that affect citrate and pH because there are well established epidemiologic differences in stone type and physiologic differences in acid-base handling by sex. Epidemiologically, younger women are more likely to have CaP stones, and this is likely because they have higher urine pH.

Exclusion Criteria:

  • History of primarily brushite, uric acid, cysteine, or struvite stones
  • History of severe acid-base abnormality, very low (less than 100mg/day) or very high (greater than 1500mg/day) urine citrate
  • Participants who cannot stop diuretic medication or alkali supplementation for the course of the study period
  • Use of drugs that can directly affect proximal tubule function (e.g., topiramate)
  • Diagnosis of complete distal renal tubular acidosis
  • Diagnosis of chronic kidney disease (eGFR <60 mL/min/1.73m²)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: CaP (Calcium Phosphate) stone patients
Defined as >50% calcium phosphate content on most recent stone analysis Age 18-70 years
Drug: Empagliflozin (Jardiance®)
Empagliflozin (Jardiance®), 10 mg tablet taken orally once daily for 4 weeks. Dispensed at baseline by the Investigational Drug Service. It will be administered at home by participants.
Active Comparator: CaOx (Calcium Oxalate) stone patients
Defined as >50% calcium oxalate content on most recent stone analysis Age 18-70 years
Drug: Empagliflozin (Jardiance®)
Empagliflozin (Jardiance®), 10 mg tablet taken orally once daily for 4 weeks. Dispensed at baseline by the Investigational Drug Service. It will be administered at home by participants.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in calcium phosphate
Time Frame: 4 weeks
Calcium phosphate supersaturation will be measured or calculated at baseline and study completion. The investigators will calculate change in calcium phosphate supersaturation for all participants and within each group.
4 weeks
Change in urine citrate
Time Frame: 4 weeks
Urine citrate will be measured or calculated at baseline and study completion. The investigators will calculate change in urine citrate for all participants and within each group.
4 weeks
Change in pH
Time Frame: 4 weeks
pH will be measured or calculated at baseline and study completion. The investigators will calculate change in pH for all participants and within each group.
4 weeks
Calcium oxalate supersaturation
Time Frame: 4 weeks
Calcium oxalate supersaturation will be measured or calculated at baseline and study completion. The investigators will calculate change in calcium oxalate supersaturation for all participants and within each group.
4 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in 24-hour urine citrate excretion (mg/day) from baseline to 4 weeks
Time Frame: 4 weeks
24-hour urine citrate excretion will be measured at baseline and study completion. The change from baseline to 4 weeks will be calculated for each participant and compared between CaP and CaOx stone groups.
4 weeks
Change in urine pH from baseline to 4 weeks
Time Frame: 4 weeks
Urine pH will be measured at baseline and study completion. The change from baseline to 4 weeks will be calculated for each participant and compared between groups.
4 weeks
Change in calcium phosphate supersaturation from baseline to 4 weeks
Time Frame: 4 weeks
Calcium phosphate supersaturation will be calculated using EQUIL2 at baseline and 4 weeks. The change will be calculated for each participant and compared between groups.
4 weeks
Change in calcium oxalate supersaturation from baseline to 4 weeks
Time Frame: 4 weeks
Calcium oxalate supersaturation will be calculated using EQUIL2 at baseline and 4 weeks. The change will be calculated for each participant and compared between groups.
4 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Chicago

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
National Institutes of Health (NIH)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 20, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 24, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 3, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 8, 2025

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB25-0673
  • 1R01DK144310 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Conditions

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