NCT04633811

Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone Formers

Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone

• Status: Active Not Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 14 (actual)
• Sponsor: University of Alabama at Birmingham · Academic / Other
• Sex: All
• Age: 19 Years – 65 Years
• Healthy volunteers: Not accepted

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.

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

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Low Oxalate Diet before Weight Loss	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.
DIETARY_SUPPLEMENT	Oral load of oxalate and sucralose before Weight Loss	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
DIETARY_SUPPLEMENT	Optifast VLCD Program	Subjects will go on a 10-week Intestive level Optifast VLCD weight loss program
DIETARY_SUPPLEMENT	Optifast VLCD Transition Phase	After completion of the 10-week Optifast VLCD Program, subjects will be weaned off the Optifast products for 4 weeks.
DIETARY_SUPPLEMENT	Low Oxalate Diet after Weight Loss	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
DIETARY_SUPPLEMENT	Oral load of oxalate and sucralose after Weight Loss	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

Timeline

• Start date: 2021-12-03
• Primary completion: 2025-12-31
• Completion: 2026-12-31
• First posted: 2020-11-18
• Last updated: 2026-03-06

Locations

1 site across 1 country: United States