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

Trial Summary

What is the purpose of this trial?

This is a single-center study that aims to better understand how diet and sex affect the risk of kidney stones in people who have had gastric bypass surgery. Subjects will be asked to follow a special (clinic-provided) diet for six days and come to a research clinic for 3 study visits.

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 data supports the idea that Special Diet for Kidney Stones Post-Bariatric Surgery is an effective treatment?

The available research shows that a controlled metabolic diet can reduce the risk of kidney stones after bariatric surgery by lowering the concentration of certain substances in urine that contribute to stone formation. Specifically, it reduces calcium oxalate supersaturation, which is a key factor in stone development. Additionally, dietary recommendations focusing on reducing oxalate intake and increasing calcium, citrate, and fluid consumption can help prevent kidney stones. These dietary changes address the increased risk of kidney stones due to changes in urine composition after surgery, such as high oxalate levels and low citrate levels. While other treatments exist, the special diet directly targets these specific risk factors, making it an effective approach for preventing kidney stones in post-bariatric surgery patients. ^{1 2 3 4 5}

What data supports the effectiveness of the treatment Special Diet for Kidney Stones Post-Bariatric Surgery?

Research suggests that dietary changes, such as reducing oxalate intake and increasing calcium, can help prevent kidney stones after bariatric surgery by addressing changes in urine composition that increase stone risk. These dietary recommendations aim to reduce high urine oxalate and increase low urine citrate and volume, which are common after surgery. ^{1 2 3 4 5}

What safety data exists for the special diet to prevent kidney stones after bariatric surgery?

The safety data for the special diet, which includes recommendations to prevent kidney stones after bariatric surgery, is primarily focused on dietary adjustments to mitigate the risk of kidney stones. These adjustments include managing dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, and vitamins D, C, B6, along with fluid intake. The diet aims to address changes in urine composition, such as high urine oxalate, low urine citrate, and low urine volume, which are linked to increased kidney stone risk after malabsorptive bariatric procedures. The data suggests that these dietary recommendations can help reduce the risk of kidney stones by addressing the metabolic changes post-surgery. ^{1 2 4 5 6}

Is the special diet for kidney stones after bariatric surgery safe for humans?

The special diet for preventing kidney stones after bariatric surgery is generally considered safe for humans, as it focuses on adjusting dietary intake of oxalate, calcium, and other nutrients to manage changes in urine composition that can lead to stones. These dietary recommendations aim to mitigate risks associated with bariatric surgery, such as increased urinary oxalate and decreased urine volume, which are linked to kidney stone formation. ^{1 2 4 5 6}

Is the special diet a promising treatment for kidney stones after bariatric surgery?

Yes, the special diet is promising because it can help reduce the risk of kidney stones by managing the body's chemical balance. It focuses on controlling the intake of certain foods and nutrients, which can prevent the formation of stones by reducing harmful substances in the urine. ^{1 4 5 6 7}

How does the special diet for kidney stones after bariatric surgery differ from other treatments?

The special diet for kidney stones after bariatric surgery is unique because it focuses on reducing urinary calcium oxalate levels by controlling dietary oxalate and calcium intake, which is crucial after bariatric surgery due to changes in how the body absorbs nutrients. Unlike other treatments, this diet specifically addresses the increased risk of kidney stones caused by metabolic changes from the surgery. ^{1 4 5 6 7}

Research Team

Prochaska Megan, MD

Principal Investigator

University of Chicago

Eligibility Criteria

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

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

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

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

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

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]

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]

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]

References

1. United States pubmed.ncbi.nlm.nih.gov

Prevalence of hyperoxaluria after bariatric surgery. [2021]

2. United States pubmed.ncbi.nlm.nih.gov

Risk Factors for Kidney Stone Formation following Bariatric Surgery. [2022]

3. England pubmed.ncbi.nlm.nih.gov

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

4. United States pubmed.ncbi.nlm.nih.gov

Controlled metabolic diet reduces calcium oxalate supersaturation but not oxalate excretion after bariatric surgery. [2021]

5. Switzerland pubmed.ncbi.nlm.nih.gov

Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation. [2021]

6. United States pubmed.ncbi.nlm.nih.gov

Kidney Stones After Bariatric Surgery: Risk Assessment and Mitigation. [2020]

7. United States pubmed.ncbi.nlm.nih.gov

Kidney stone risk following modern bariatric surgery. [2021]