Kidney StoneNCT04633811
Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone Formers
A study testing Low Oxalate Diet before Weight Loss, Oral load of oxalate and sucralose before Weight Loss and Optifast VLCD Program in people with Kidney Stone, run by University of Alabama at Birmingham at 1 site in United States.
Trial summary
This protocol seeks to determine if weight reduction with the Optifast VLCD program leads to reduced contribution of endogenous oxalate synthesis and dietary oxalate absorption to the urinary oxalate pool in obese calcium oxalate stone formers. Read more about this study
- Who is it for?
- Ages 19 to 65 years
- Conditions the study is for
- Kidney Stone
- What is being tested?
- Low Oxalate Diet before Weight Loss, Oral load of oxalate and sucralose before Weight Loss and Optifast VLCD Program
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Dec 2021to 31 Dec 2026
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- First time or recurrent calcium oxalate stone formers defined as composition of most recent stone >50% calcium oxalate without uric acid component
- Last stone passage or removal greater than 3 months prior to screening
- Body Mass Index (BMI) >35 kg/m2
- Able to provide consent
- Hemoglobin A1C <6.5%
- Normal fasting blood CMP: Normal serum Na, K, Cl, CO2, Calcium, Albumin, AST, ALT <2 times upper limit of normal, Glucose <126 mg/dl, eGFR >60 ml/min/1.73 m2.
Show all 16Show fewer
- 24-hour urine collection with creatinine within 20% of gender appropriate (mg creat/kg body weight) and consistent between collections (within 20% of each other)
- Willing to ingest menus prepared at the University of Alabama and University of Texas Southwestern Clinical Research Units
- Willing to consume the Optifast VLCD diet
- Willing to ingest menus prepared in Metabolic kitchen. No food allergies or intolerance to any of the foods in study menus. Substitutions for lactose intolerance will be made.
- Willing to avoid vigorous exercise during eucaloric, low-oxalate dietary phase
- Willing to stop use of weight-loss medications
- Willing to stop for 14 days before and during study: medications for stone prevention including diuretics, potassium citrate, allopurinol, febuxostat, and calcium, nutritional, or herbal supplements
- Those with controlled hypertension (systolic blood pressure <160 mmHg, diastolic <90 mmHg) will be included.
- Those without severe dyslipidemia (LDL <200 mg/dL, HDL >30 mg/dL, and triglycerides <250 mg/dL) will be included. Treated and controlled dyslipidemia is accepted
- Smoking/chewing tobacco/vaping will be allowed
Who cannot join
- Renal colic or past stone surgery in the past 3 months
- Estimated Glomerular Filtration Rate (eGFR) less than 60 ml/min/1.73m2
- History of type 2 diabetes or screening hgb A1c greater than or equal to 6.5%
- Alcohol or drug abuse. Alcohol consumption >12 units per week and/or unwillingness to abstain from alcohol consumption 2 days before and during the study.
- Mental/medical condition likely to impede study completion
- Current/planned pregnancy or breastfeeding in coming 6 months, unwillingness to use effective method of birth control during the study for individuals of childbearing potential.
Show all 16Show fewer
- Planned vacation in coming 4 months
- Febrile illness including flu/common cold/COVID-19 within 21 days of study start
- Primary or enteric hyperoxaluria
- Gastrointestinal disorder or surgery that impacts oxalate transport
- Cirrhosis, pancreatic or biliary disorder, porphyria, gout
- Malignancy treated within the past 12 months
- Nephrotic syndrome, neurogenic bladder, urinary diversion
- History of primary hyperparathyroidism, cystinuria, renal tubular acidosis, sarcoidosis, cystic fibrosis
- Uncontrolled hypertension, myocardial infarction in past 6 months, unstable angina, congestive heart failure
- Medications: Topiramate, acetazolamide, zonisamide, diuretics, SGLT2-inhibitors, immunosuppressants
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Alabama at Birmingham
Birmingham, Alabama, 35243
About this study
Official title: Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone
This protocol seeks to determine if weight reduction with the Optifast VLCD program leads to reduced contribution of endogenous oxalate synthesis and dietary oxalate absorption to the urinary oxalate pool in obese calcium oxalate stone formers.
Read the detailed description
Obese adults (≥19 and ≤ 65 years) with a history of calcium oxalate kidney stone disease will be recruited at both University of Alabama at Birmingham (UAB) and University of Texas South Western (UTSW). Following consent, subjects will complete a screening phase, which includes (1) a meeting with a dietitian to ensure willingness to consume controlled ultra-low oxalate diets and determine anthropometric measurements and blood pressure, (2) collection of fasted blood and 2 x 24-hour urine specimens on self-choice diets to determine general health status and urinary chemistries, respectively, (3) completion of a 7-day run-in diet that includes the use of one serving of an Optifast meal daily to assess tolerance to Optifast VLCD® products. Participants will then consume an eucaloric, ultra-low oxalate controlled diet for 6 days. The controlled dietary phase involves 2 days of dietary equilibration, followed by 2 x 24-hour urine collections, and on the 5th day a dietary oxalate/sucralose oral load. Following the dietary oxalate/sucralose oral load, subjects will have blood collected every 30 minutes and collect 1-hour urines. Participants will then go on an intensive 14-week Optifast VLCD® Program to induce weight loss. At the end of this Optifast VLCD® Program participants will again perform the low oxalate controlled diet and dietary/sucralose oral load study. A total of 40 adult obese calcium oxalate kidney stone formers (20 male and 20 female) will be enrolled (20 at UAB and 20 at UTSW).
- Conditions
- Kidney Stone
- Being tested
- Low Oxalate Diet before Weight Loss, Oral load of oxalate and sucralose before Weight Loss, Optifast VLCD Program, Optifast VLCD Transition Phase, Low Oxalate Diet after Weight Loss
- Medical subject headings
- Kidney Calculi
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low Oxalate Diet before Weight LossDietary supplement
Subjects will be instructed to ingest a controlled diet low in oxalate for a total of 6 days. 2 x 24 hour urines will be collected on days 3 and 4.
Oral load of oxalate and sucralose before Weight LossDietary supplement
Subjects will ingest 100mg carbon-13 oxalate, and 1 gram of sucralose on day 5 of the 6-day low oxalate diet phase. Following the oral load, blood and urine will be collected every 30 minutes and hourly, respectively
Optifast VLCD ProgramDietary supplement
Subjects will go on a 10-week Intestive level Optifast VLCD weight loss program
Optifast VLCD Transition PhaseDietary supplement
After completion of the 10-week Optifast VLCD Program, subjects will be weaned off the Optifast products for 4 weeks.
Low Oxalate Diet after Weight LossDietary supplement
Subjects will be instructed to ingest a controlled diet low in oxalate for a total of 11 days and collect 2 x 24 hour urines on days 8 and 9
Oral load of oxalate and sucralose after Weight LossDietary supplement
Subjects will ingest 100mg carbon-13 oxalate, and 1 gram of sucralose on day 10 of the 11-day low oxalate diet phase. Following the oral load, blood and urine will be collected every 30 minutes and hourly, respectively
| Study group | Role | What they receive |
|---|---|---|
| Controlled Diet and Weight Loss Program | Experimental | Subjects will consume a low oxalate diet with blood and urine collections to establish baseline levels before undergoing a weight loss program with Optifast VLCD products. After completing the weight loss program, subjects will once again consume a low oxalate diet with blood and urine collections to observe any changes that may have occurred due to the weight loss. Receives: Dietary Supplement: Low Oxalate Diet before Weight Loss; Dietary Supplement: Oral load of oxalate and sucralose before Weight Loss; Dietary Supplement: Optifast VLCD Program; Dietary Supplement: Optifast VLCD Transition Phase; Dietary Supplement: Low Oxalate Diet after Weight Loss; Dietary Supplement: Oral load of oxalate and sucralose after Weight Loss |
What is being measured
The primary outcome is the main question the study is designed to answer.
Measurement of 24 hour urinary oxalate excretion
Subjects will ingest a controlled diet low in oxalate and collect 2 x 24-hour urines before and after the Optifast VLCD Program. The utilization of a low oxalate diet allows assessment of the change in contribution of endogenous oxalate synthesis to the urinary oxalate pool.
Measured: 4 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2020
- Study start3 Dec 2021
- Primary completion31 Dec 2025
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Kidney StoneStudies of the same condition, open and under way.
- More trials run by University of Alabama at BirminghamThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Alabama at Birmingham
- Sponsor type
- University, hospital or other
- Collaborators
- University of Texas Southwestern Medical Center, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Responsible party
- Principal investigator, Dean Assimos, MD, University of Alabama at Birmingham
- Investigators
- Dean Assimos, MD, Principal investigator, University of Alabama at Birmingham
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04633811
- Sponsor's protocol ID
- IRB-300006133
- Other IDs
- R01DK128160
- Status last verified
- Mar 2026
- First submitted
- 11 Nov 2020
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No