Influence of Obesity on Oxalate Metabolism and Handling in Calcium Oxalate Stone Formers

August 25, 2026 updated by: Dean Assimos, MD, University of Alabama at Birmingham
The primary goals of this study are to determine the contribution of dietary oxalate absorption, renal oxalate handling, and endogenous oxalate synthesis to urinary oxalate excretion in normal Body Mass Index (BMI) and obese calcium oxalate kidney stone formers.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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.

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 (Actual)

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.
22

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.
  • Not Applicable

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

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35243-3353
        • University of Alabama at Birmingham
    • Texas
      • Dallas, Texas, United States, 75390
        • University of Texas Southwestern Medical Center

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

19 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Normal Body Mass Index (≥ 18.5 to < 25); Obese Body Mass Index (≥ 30 to ≤ 45)
  • Able to provide informed consent
  • Willingness to consume controlled diet
  • Composition of most recent stone > 50% calcium oxalate, no uric acid component
  • First time or recurrent calcium oxalate stone former
  • 24-hour urine collections with creatinine values within 20% of appropriate ratio of creatinine (mg)/body weight (kg) for gender, and with creatinine values that are consistent between collections (within 20% of each other)
  • Willingness to stop supplements [vitamins, Ca (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics] for 14 days before start and during study
  • Willingness to not undertake vigorous exercise during the controlled dietary study
  • Normal fasting blood Comprehensive Metabolic Panel
  • Hemoglobin A1c < 6.5%
  • No food allergies or intolerance to any of the food in study menus
  • Permitted/willing to discontinue medications for kidney stone prevention, including thiazides, allopurinol, and febuxostat and citrate preparations, for 14 days before start and during the studies. They will be instructed to restart these medications at the conclusion of the study

Exclusion Criteria:

  • Diabetes
  • Abnormal fasting comprehensive metabolic panel (CMP)
  • Hemoglobin A1c (HbA1c) result ≥ 6.5%
  • Gout
  • Estimated Glomerular Filtration Rate (eGFR) <60 ml/min/1.73m^2
  • Primary hyperoxaluria
  • Cystic fibrosis
  • Cystinuria
  • Uric acid stone former
  • Utilization of immunosuppressive medication
  • Nephrotic syndrome
  • Enteric hyperoxaluria
  • Gastrointestinal disorder that could impact oxalate transport
  • Sarcoidosis
  • Uncontrolled hypertension
  • Renal tubular acidosis
  • Primary hyperparathyroidism
  • Liver disease
  • Neurogenic bladder
  • Urinary diversion
  • Chronic diarrhea
  • Bariatric surgery
  • Active malignancy or treatment for malignancy within 12 months prior to screening
  • Pregnancy
  • Breast feeding/nursing
  • Females of child bearing age who are not able to use an effective method of birth control during the study
  • Mental/medical condition that is likely to impede successful study completion
  • Illness including flu / common cold / fever 14 days before study and during study
  • Diarrhea or other abnormal gastrointestinal event (e.g. abnormal bowel movements) 14 days before study or during study
  • Antibiotic use within last 6 months (based on recommendations of the NIH Human Microbiome Project, Protocol A)
  • Inability or unwillingness to undergo MRI

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: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group 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.
Experimental: Controlled Dietary Study
Participants will consume the controlled diet for five days. After one day on the diet, subjects will provide three 24-hour urine collections. On the last dayof the diet, subjects will come in a fasted state to ingest a small amount of carbon-13 oxalate and sucralose, with hourly urine collections and blood samples being taken before and after the ingestion.
Other: Controlled Diet
Participant will consume a controlled low oxalate diet for five days
Dietary supplement: Carbon-13 Oxalate and Sucralose Ingestion
Subjects will ingest a small amount of carbon-13 oxalate and sucralose, dissolved in water.

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
Urinary Oxalate Excretion
Time Frame: Baseline through Day 5
Urinary oxalate excretion from urine samples will be measured as mg/day
Baseline through Day 5

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 Alabama at Birmingham

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)
University of Texas, Southwestern Medical Center at Dallas

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Dean Assimos, MD, University of Alabama at Birmingham

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.
September 1, 2021

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.
December 1, 2026

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.
August 1, 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).
April 1, 2020

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.
April 1, 2020

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.
April 3, 2020

Study Record Updates

Last Update Posted (Actual)

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.
August 26, 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.
August 25, 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.
August 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.
  • IRB300004693-OHM
  • UAB (Other Identifier: UAB)
  • P20DK119788 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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