Special Diet for Kidney Stones Post-Bariatric Surgery

Overseen By Prochaska Megan, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Chicago

Disqualifiers: Renal diseases, Bladder problems, Vitamin D deficiency

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 4

28 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how a special diet might affect the risk of kidney stones in individuals who have undergone gastric bypass surgery. Researchers aim to determine if diet and biological sex influence the development of kidney stones after this weight-loss surgery. Participants will follow a specific diet provided by the clinic and attend three study visits. Ideal candidates for this trial are those approved for bariatric surgery at the University of Chicago Medicine with no history of kidney stones or kidney diseases. As an unphased trial, this study offers participants the chance to contribute to groundbreaking research that could enhance post-surgery outcomes for many.

Do I need to stop my current medications for the trial?

The trial protocol does not specify whether you need to stop taking your current medications.

Do I need to stop my current medications for this trial?

The trial information does not specify whether you need to stop taking your current medications.

What prior data suggests that this special diet is safe for post-bariatric surgery patients?

Research has shown that special diets to prevent kidney stones after weight-loss surgery are generally safe. These diets focus on dietary changes to lower the risk of kidney stones, which can become more common after such surgeries.

Studies indicate that weight-loss surgery can increase the risk of kidney stones by altering how the body processes certain nutrients. However, following a special diet can help reduce this risk. The diet typically involves adjusting the intake of specific foods to maintain kidney health.

Overall, the special diet studied is considered safe and usually does not cause side effects. For those considering joining a trial with this diet, existing research supports its safety. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores the potential of a special diet to prevent kidney stones in patients who have undergone bariatric surgery. Unlike current treatments, which often involve medication or lifestyle changes after stones have formed, this approach aims to proactively prevent stones by tailoring the diet specifically to patients undergoing Roux-en-y gastric bypass or sleeve gastrectomy. By carefully monitoring dietary intake and conducting blood and urine tests before and after surgery, researchers hope to identify dietary patterns that minimize stone formation, offering a proactive solution to a common post-surgery issue. This trial could lead to a simple yet effective strategy to enhance long-term health outcomes for bariatric surgery patients.

What evidence suggests that this special diet could be effective for preventing kidney stones post-bariatric surgery?

Research has shown that people who undergo weight-loss surgeries, such as gastric bypass or sleeve gastrectomy, are more likely to develop kidney stones. Studies have found that this risk increases by 7.6% over five years post-surgery, particularly with certain procedures. This occurs partly because the surgery can lead to increased absorption of oxalate, a substance in some foods that can form stones. In this trial, participants will follow a special diet designed to lower this risk. These diets focus on reducing oxalate levels and other factors that contribute to stone formation, potentially preventing kidney stones in patients after surgery. ^{2 4 6 7 8}

Who Is on the Research Team?

Prochaska Megan, MD

Principal Investigator

University of Chicago

Are You a Good Fit for This Trial?

This trial is for individuals approved for bariatric surgery at the University of Chicago Medicine, who have no personal or family history of kidney stones. It's not open to those with vitamin D deficiency (levels below 25ng/mL), primary renal diseases, impaired kidney function (eGFR < 90), or known bladder voiding issues.

Inclusion Criteria

I am approved for and scheduled to have bariatric surgery at the University of Chicago Medicine.

You have never had kidney stones, and no one in your family has had kidney stones.

Exclusion Criteria

My kidney function is impaired.

I have issues emptying my bladder.

Your blood test shows that you have very low levels of vitamin D.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Pre-Surgery Assessment

Participants complete a diet record and a 24-hour urine collection before surgery

1 month

2 visits (1 in-person, 1 virtual)

Post-Surgery Assessment (1 month)

Participants consume a 3-day fixed diet and present to the clinical research center for timed blood and urine draws

4 days

1 visit (in-person)

Post-Surgery Assessment (1 year)

Participants consume a 3-day fixed diet and present to the clinical research center for timed blood and urine draws

4 days

1 visit (in-person)

Follow-up

Participants are monitored for changes in urine calcium oxalate supersaturation and other parameters over time

13 months

What Are the Treatments Tested in This Trial?

Interventions

• Special diet

Trial Overview

The study investigates how a special diet affects the risk of developing kidney stones after gastric bypass surgery. Participants will follow this clinic-provided diet for six days and attend three research clinic visits.

How Is the Trial Designed?

Group I: Sleeve gastrectomy subjects Experimental Treatment 1 Intervention

Inclusion Criteria: Age 18-70. Participants pre-sleeve gastrectomy who are approved and sleeve gastrectomy in the Bariatric Surgery Center at the UCM. Exclusion Criteria: Patients with primary kidney diseases, kidney stone disease, or kidney impairment (eGFR \< 90). Patients with known bladder voiding problems. Participants will complete a diet record and a 24-hour urine collection both before and after surgery. Participants will consume a 3 day fixed diet and present to the clinical research center for timed blood and urine draws. They will do this before and twice after (1 month and 1 year) surgery.

Group II: Roux-en-y gastric bypass subjects Experimental Treatment 1 Intervention

Inclusion Criteria: Age 18-70. Participants pre-Roux-en-y gastric bypass (RYGB) who are approved and planned for Roux-en-y gastric bypass surgery in the Bariatric Surgery Center at the UCM. Exclusion Criteria: Patients with primary kidney diseases, kidney stone disease, or kidney impairment (eGFR \< 90). Patients with known bladder voiding problems. Participants will complete a diet record and a 24-hour urine collection both before and after surgery. Participants will consume a 3 day fixed diet and present to the clinical research center for timed blood and urine draws. They will do this before and twice after (1 month and 1 year) surgery.

Who Is Running the Clinical Trial?

University of Chicago

Lead Sponsor

Trials

1,086

Recruited

844,000+

Published Research Related to This Trial

Bariatric surgery is effective for long-term weight loss but can lead to complications like hyperoxaluria, which increases the risk of kidney stones due to changes in urinary metabolism.

The review suggests dietary modifications, including managing oxalate and calcium intake, to mitigate the risk of urinary stone formation after surgery, highlighting the importance of nutrition in post-operative care.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation. Ormanji, MS., Rodrigues, FG., Heilberg, IP.[2021]

In a study of 58 nonstone forming adults who underwent bariatric surgery, it was found that 74% exhibited hyperoxaluria, meaning they had higher than normal levels of oxalate in their urine, which can lead to kidney stones.

The study revealed that patients who underwent biliopancreatic diversion-duodenal switch procedures had even higher oxalate excretion compared to those who had Roux-en-Y surgery, indicating that certain types of bariatric surgery may carry a greater risk for developing hyperoxaluria.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prevalence of hyperoxaluria after bariatric surgery. Patel, BN., Passman, CM., Fernandez, A., et al.[2021]

Bariatric surgeries like Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) significantly increase the risk of developing kidney stones, particularly RYGB, which can triple the risk of calcium oxalate stones compared to obese individuals without surgery.

The increased risk of kidney stones after these surgeries is mainly due to changes in urine composition, such as higher urinary oxalate and lower citrate levels, but these risks can be managed through patient education and dietary or pharmacological interventions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kidney Stones After Bariatric Surgery: Risk Assessment and Mitigation. Espino-Grosso, PM., Canales, BK.[2020]

Bariatric surgery has been associated with metabolic changes that increase the risk of kidney stones, as highlighted by various studies over the past decade, although many of these studies had limitations such as being retrospective or lacking proper controls.

The review discusses the urinary chemistry profiles linked to kidney stone formation in bariatric patients and suggests potential therapies to manage hyperoxaluria, which is a key factor in stone disease, based on findings from a new experimental animal model.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kidney stone risk following modern bariatric surgery. Gonzalez, RD., Canales, BK.[2021]

Malabsorptive bariatric surgery increases the risk of kidney stones due to changes in urine composition, such as higher oxalate levels and lower citrate and volume, while restrictive surgeries do not carry this risk.

Dietary recommendations post-surgery may help reduce the risk of kidney stones by addressing the unfavorable changes in urine composition, highlighting the importance of understanding these risks for better patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Risk Factors for Kidney Stone Formation following Bariatric Surgery. Prochaska, M., Worcester, E.[2022]

Bariatric surgery leads to significant cardiovascular benefits and improved survival rates in overweight individuals, along with consistent reductions in albuminuria and proteinuria after weight loss.

However, it also increases the risk of developing kidney stones due to hyperoxaluria, which can lead to serious renal complications, highlighting the need for monitoring and potential treatment strategies post-surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Bariatric surgery and the kidney-much benefit, but also potential harm. Ritz, E.[2020]

A controlled metabolic diet that is low in oxalate and normal in calcium significantly reduced urinary calcium oxalate supersaturation in 9 subjects with a history of kidney stones after bariatric surgery, from 1.97 to 1.13 delta Gibbs (P < .01).

Despite the reduction in supersaturation, the diet did not significantly lower urinary oxalate excretion, suggesting that additional strategies, such as oral calcium supplements, may be needed to effectively manage hyperoxaluria in these patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Controlled metabolic diet reduces calcium oxalate supersaturation but not oxalate excretion after bariatric surgery. Pang, R., Linnes, MP., O'Connor, HM., et al.[2021]

Citations

1.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC5361755/

Kidney Stones After Bariatric Surgery: Risk Assessment ...

Of note, a 1.5-fold increase in oxalate absorption was observed after oral oxalate load 12 months after surgery, which correlated with a similar increase in ...

2.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC8171111/

Risk Factors for Kidney Stone Formation following Bariatric ...

This review will discuss the risk of kidney stones after bariatric surgery and recommendations for mitigating that risk.

3.

nature.com

nature.com/articles/s41598-024-78771-y

Bariatric surgery does not affect kidney stone disease

This risk of developing urolithiasis in bariatric patients increases by 7.6% for 5 years post-surgery and higher after malabsorptive procedures.

4.

sciencedirect.com

sciencedirect.com/science/article/pii/S1743919116310342

Review Nephrolithiasis after bariatric surgery

Both obesity and bariatric surgery are associated with an increased risk for nephrolithiasis. Stone formation risk varies with the type of bariatric surgical ...

5.

mdpi.com

mdpi.com/2072-6643/12/5/1442

Dietary Recommendations for Bariatric Patients to Prevent ...

The authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation.

6.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC4167184/

KIDNEY STONE INCIDENCE AND METABOLIC URINARY ...

Bariatric surgery has been associated with increased metabolic kidney stone risk and post-operative stone formation.

7.

withpower.com

withpower.com/trial/phase-kidney-calculi-10-2020-f93af

Special Diet for Kidney Stones Post-Bariatric Surgery

The special diet for preventing kidney stones after bariatric surgery is generally considered safe for humans, as it focuses on adjusting dietary intake of ...

8.

link.springer.com

link.springer.com/article/10.1007/s00345-022-04268-w

Dietary weight loss strategies for kidney stone patients

An energy-restricted diet with or without meal replacement could be a promising weight loss strategy for overweight kidney stone patients.