Kidney StoneNCT06331546
Gut Oxalate Absorption in Calcium Oxalate Stone Disease
A study testing Low-oxalate diet, High-oxalate diet and soluble oxalate gut absorption test in people with Kidney Stone and Kidney Calculi, run by University of Alabama at Birmingham at 2 sites in United States.
Trial summary
The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased absorption of dietary oxalate, which would lead to increased urinary excretion of oxalate. Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Kidney Stone, Kidney Calculi, Urolithiasis
- What is being tested?
- Low-oxalate diet, High-oxalate diet and soluble oxalate gut absorption test
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 80 participants
- Where
- 2 sitesUnited States
- Study dates
- 17 Apr 2024to 31 Dec 2031
- 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 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- age 18-80 yrs
- Body Mass Index > 18.5 kg/m2
- Normal fasting serum electrolytes on comprehensive metabolic profile
- Willing to ingest fixed diets
- Willing to stop supplements (vitamins including vitamin C, calcium (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics) for 2 weeks before start and during study.
- For stone formers: first time or recurrent Calcium Oxalate stone former. Composition of most recent stone ≥ 50% calcium oxalate if available, uric acid component <20%
Who cannot join
- Chronic Kidney Disease stage 4-5
- Primary hyperoxaluria, Enteric (secondary) hyperoxaluria
- Liver, bowel, endocrine or renal diseases (other than idiopathic Calcium Oxalate kidney stones) or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results, including: Cystic fibrosis, Celiac disease, Cystinuria, Uric acid stone former, Nephrotic syndrome, Sarcoidosis, Renal tubular acidosis, Primary hyperparathyroidism, Neurogenic bladder, Urinary diversion, Chronic diarrhea, Bariatric surgery, Inflammatory bowel disease
- Pregnancy or breast-feeding
- Incompatible dietary requirements with the study, food allergies or intolerance to any of the foods in study menus
- Active malignancy or treatment for malignancy within 12 months prior to screening
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- Utilization of immunosuppressive medication
- Uncontrolled hypertension or diabetes
- Diabetes type 1
- Chronic NSAID use
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States2 sites, 2 recruiting
- Recruiting
University of Alabama at Birmingham
Birmingham, Alabama, 35294
Sonia Fargue, PhD, 205-9756932, kidneystone@uabmc.edu
Research Coordinator, 205-9345712, kidneystone@uabmc.edu
- Recruiting
UTSW
Dallas, Texas, 75390
Naim Maalouf, MD, Naim.Maalouf@UTSouthwestern.edu
Peter Gales, Peter.Gales@UTSouthwestern.edu
About this study
Official title: Gastrointestinal Oxalate Absorption in Calcium Oxalate Stone Disease
The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased absorption of dietary oxalate, which would lead to increased urinary excretion of oxalate.
The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones.
Participants will
- ingest fixed diets containing low and moderately high amounts of oxalate for 5 days at a time
- ingest a soluble form of oxalate and sugar preparations to test gut permeability
- collect urine, blood, stool and breath sample during the fixed diets and the soluble oxalate test
Read the detailed description
In this study the investigators propose to measure the net gastrointestinal absorption of oxalate both by food-bound oxalate, using low- (<60 mg/day) and high- (250-300 mg/day) oxalate diets (600-800 mg daily calcium in both), and by the soluble 13C2-oxalate oral test in both Calcium Oxalate Kidney Stone patients and matched controls.
Phase 1. Screening and low-oxalate diet 24-hr urinary excretions. Between the University of Alabama at Birmingham (UAB) and the University of Texas Southwestern Medical Center (UTSW), the study will enroll 40 subjects with idiopathic Calcium Oxalate Kidney Stone (20 Males/20 Females) and 40 non-kidney stone forming controls (20 Males/20 Females). Participants in the two groups will be matched for age (within 10 yrs) and gender. Screening will include blood complete metabolic profile and two 24-hr urine specimens collected at home on self-choice diets and anthropometric measurements.
Participants will then ingest the controlled low-oxalate (<60 mg/d) diet for 5 consecutive days and collect two 24-hr urines after 2 days of dietary equilibration.
Phase 2. 13C2-Oxalate gut absorption tests. On Day 5, participants will arrive after an overnight fast in the research unit to undergo the 13C2-oxalate absorption test. After a 1-hour baseline urine collection, they will ingest an oral load containing 100 mg 13C2-oxalate and 1 g sucralose, dissolved in bottled water. For the next 9 hrs, blood and urine will be collected hourly, and breath as more time points. They will remain on the fixed diet for 24 hrs with a breakfast 2 hours after the load, lunch 6 hrs post-load, and dinner at home 12 hrs post-load. They will collect the remainder of their 24-hr urine at home and the totality of the stool eliminated during the first 24 hrs after the load using kits provided.
Phase 3. High-oxalate diet 24-hr urinary excretions. After a minimum of 1 week wash-out period, during which participants will eat freely, participants will consume the high oxalate (250-300 mg/day) diet for the next 4 days. Two 24-hr urine specimens will be collected after 2 days of equilibration and a fasting blood draw on the morning of Day 5.
.
- Conditions
- Kidney Stone, Kidney Calculi, Urolithiasis, Urolithiasis, Calcium Oxalate, Nephrolithiasis, Nephrolithiasis, Calcium Oxalate
- Being tested
- Low-oxalate diet, High-oxalate diet, soluble oxalate gut absorption test
- Medical subject headings
- Kidney Calculi, Urolithiasis, Nephrolithiasis, Calcium Oxalate, Nephrolithiasis, Hyperoxaluria
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low-oxalate dietDietary supplement
4 days of fixed eucaloric diet with low oxalate (<60 mg/day), normal calcium content (600-1000 mg/day)
High-oxalate dietDietary supplement
4 days of fixed eucaloric diet with moderately high oxalate (250-300 mg/day), normal calcium content (600-1000 mg/day)
soluble oxalate gut absorption testOther
Oral ingestion of 13C2-oxalate and sucralose.
| Study group | Role | What they receive |
|---|---|---|
| Idiopathic Calcium Oxalate Kidney Stone Patients | Experimental | Low and High oxalate fixed diets. Soluble oxalate absorption test. Receives: Dietary Supplement: Low-oxalate diet; Dietary Supplement: High-oxalate diet; Other: soluble oxalate gut absorption test |
| Healthy non-kidney stone forming individuals | Active comparator | Low and High oxalate fixed diets. Soluble oxalate absorption test. Receives: Dietary Supplement: Low-oxalate diet; Dietary Supplement: High-oxalate diet; Other: soluble oxalate gut absorption test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Net Gastrointestinal absorption of food-bound oxalate
difference between 24-hour urinary oxalate excretion on the high oxalate diet and the low oxalate diet, normalized to the difference in dietary oxalate composition of the two diets (%)
Measured: 4 day
Secondary outcomes (2)
Absorption of soluble 13C2-oxalate
Proportion of 13C2-oxalate recovered in urine to the amount orally ingested (%)
Measured: 1 day
Estimated endogenous oxalate synthesis (oxalate mg/day)
24-hour urinary oxalate excretion on the low oxalate diet (mg/day)
Measured: 2 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Mar 2024
- Study start17 Apr 2024
- Primary completion31 Dec 2030 (estimated)
- Study completion31 Dec 2031 (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
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 80 participants (estimated)
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, Sonia Fargue, University of Alabama at Birmingham
- Investigators
- Sonia Fargue, PhD, Principal investigator, University of Alabama at Birmingham
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06331546
- Sponsor's protocol ID
- IRB300004693-GIA
- Other IDs
- R01DK137784
- Status last verified
- Oct 2026
- First submitted
- 19 Mar 2024
- Last updated
- 13 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No