Weight Loss for Kidney Stones

Overseen By Jane Vines, MPH

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Alabama at Birmingham

Must not be taking: Diuretics, SGLT2-inhibitors

Disqualifiers: Diabetes, Pregnancy, Hypertension, Gout, others

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

Approved in 3 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 1

14 Participants Needed

Trial Summary

What is the purpose of this trial?

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.

Will I have to stop taking my current medications?

You will need to stop taking weight-loss medications and certain medications for stone prevention, like diuretics, potassium citrate, allopurinol, febuxostat, and calcium, nutritional, or herbal supplements, for 14 days before and during the study.

What data supports the effectiveness of the treatment Optifast VLCD Program for weight loss in kidney stone patients?

Research shows that a low-calorie diet can help reduce factors in urine that contribute to kidney stones in obese adults. Additionally, very-low-calorie diets (VLCD) have been effective in treating extreme obesity, which may indirectly help with kidney stone management. ^{1 2 3 4 5}

Is the Optifast VLCD Program safe for humans?

The Optifast VLCD Program, a very low calorie diet, has been used safely in patients with acute kidney injury (a sudden decrease in kidney function) under close medical supervision, with no adverse effects on kidney function or electrolytes (minerals in the body). ^{6 7 8 9 10}

How does the Optifast VLCD Program treatment differ from other treatments for kidney stones?

The Optifast VLCD Program is a very low-calorie diet designed for weight loss, which may help reduce the risk of kidney stones by addressing obesity, a known risk factor. Unlike surgical options like bariatric surgery, which can increase kidney stone risk, this diet focuses on controlled calorie intake to manage weight without altering the body's metabolism in ways that could increase stone formation. ^{3 4 6 11 12}

Research Team

Dean G Assimos, MD

Principal Investigator

University of Alabama at Birmingham

Eligibility Criteria

This trial is for obese individuals with a BMI over 35 who have had calcium oxalate kidney stones but no stone issues in the last 3 months. Participants must not have diabetes, severe dyslipidemia, or recent surgery and should be willing to follow specific dietary guidelines and avoid certain medications.

Inclusion Criteria

Willing to consume the Optifast VLCD diet

My last kidney stone was passed or removed over 3 months ago.

Your hemoglobin A1C level is lower than 6.5%.

Exclusion Criteria

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

I do not have uncontrolled high blood pressure or recent serious heart issues.

I have a history of conditions like hyperparathyroidism or cystic fibrosis.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

1 visit (in-person)

Controlled Diet Phase

Participants consume an eucaloric, ultra-low oxalate controlled diet for 6 days, including dietary equilibration and oxalate/sucralose oral load

6 days

Multiple visits for blood and urine collection

Weight Loss Program

Participants undergo a 14-week Optifast VLCD® Program to induce weight loss

14 weeks

Regular visits for monitoring and support

Post-Weight Loss Controlled Diet Phase

Participants repeat the low oxalate controlled diet and dietary/sucralose oral load study to observe changes after weight loss

6 days

Multiple visits for blood and urine collection

Follow-up

Participants are monitored for safety and effectiveness after the weight loss program

4 weeks

Treatment Details

Interventions

• Optifast VLCD Program

Trial Overview The study tests if the Optifast VLCD weight loss program can reduce endogenous oxalate synthesis contributing to urinary oxalate in obese people prone to kidney stones. It includes phases of low-oxalate diets and oral loads of oxalate/sucralose before and after weight loss.

Participant Groups

Group I: Controlled Diet and Weight Loss Program Experimental Treatment 6 Interventions

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.

Optifast VLCD Program is already approved in United States, European Union for the following indications:

Approved in United States as Optifast for:

• Dietary management of obesity
• Preparation for bariatric surgery

Approved in European Union as Optifast for:

• Dietary management of obesity

Who Is Running the Clinical Trial?

University of Alabama at Birmingham

Lead Sponsor

Trials

1,677

Recruited

2,458,000+

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Trials

2,513

Recruited

4,366,000+

University of Texas Southwestern Medical Center

Collaborator

Trials

1,102

Recruited

1,077,000+

Findings from Research

A combined nutritional and medical therapy approach significantly improved urinary risk factors for stone disease in 137 patients over an average follow-up of 14.39 months, with notable improvements in hypocitraturia (67% of patients), hypercalciuria (82%), and hyperuricosuria (72%).

The study highlights that individualized medical management based on specific urinary abnormalities can effectively reduce stone risk, especially for patients who do not respond to dietary changes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Patient-centered medical therapy for nephrolithiasis. Marchini, GS., Ortiz-Alvarado, O., Miyaoka, R., et al.[2013]

In a study of 57 patients with recurrent urolithiasis followed for 5 years, individualized dietary advice and pharmacological treatment led to significant reductions in urinary excretion of calcium, uric acid, and sodium.

The combination of these interventions also resulted in a significant decrease in the recurrence of kidney stones compared to pre-treatment levels, highlighting the effectiveness of tailored clinical therapy and nutrition in managing urolithiasis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Influence of clinical therapy and nutritional counseling on the recurrence of urolithiasis. Damasio, PC., Amaro, CR., Padovani, CR., et al.[2019]

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]

A 12-week low-calorie diet for obese adults with idiopathic calcium oxalate kidney stones did not lead to a decrease in 24-hour urinary lithogenic parameters, indicating that weight loss alone may not reduce stone risk.

Despite some participants achieving a BMI below 30 kg/m², the study suggests that calcium oxalate stone formation is likely influenced by factors beyond just body weight, highlighting the complexity of this condition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones. Danilovic, A., Marchini, GS., Pucci, ND., et al.[2022]

A very-low-calorie diet (VLCD) was effective in promoting significant weight loss and improving lipid profiles in 28 extremely obese subjects over one month, indicating its potential as a safe treatment for obesity.

The VLCD also led to a decrease in hyperinsulinism, which, while not statistically significant, suggests metabolic benefits that could reduce the risk of atherosclerosis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Treatment of extreme obesity with a very low calorie diet]. Ivković-Lazar, T.[2009]

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]

A very low calorie diet (VLCD) was safely administered to a patient with acute kidney injury (AKI) during a 15-week hospital stay, leading to the resolution of AKI by week 5 without adverse effects on kidney function or electrolytes.

The patient achieved significant weight loss of 76 kg, suggesting that VLCD can be an effective and safe intervention for managing obesity in hospitalized patients with AKI when closely monitored by medical professionals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Use of a Very Low Calorie Diet for Weight Loss in a Patient with Acute Kidney Injury and Class III Obesity: A Case Study. Parra Guasca, M., Manafi, M., Parnham, A., et al.[2023]

In a study of 6640 adults over one year, those on very-low-calorie diets (VLCD) experienced a significantly greater weight loss (-11.1 kg) compared to those on low-calorie diets (LCD) (-8.1 kg), but this came with increased risks.

The risk of developing symptomatic gallstones requiring hospital care was three times higher in the VLCD group compared to the LCD group, with 48 cases in VLCD versus 14 in LCD, indicating a notable safety concern for VLCDs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Risk of symptomatic gallstones and cholecystectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study. Johansson, K., Sundström, J., Marcus, C., et al.[2021]

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]

A systematic review of seven studies involving 2498 patients showed that bariatric surgery significantly alters urinary composition, leading to decreased levels of calcium, citrate, and urate, while increasing oxalate levels.

These changes in urinary composition, particularly the decrease in citrate and increase in oxalate, are associated with a higher risk of kidney stone disease (KSD) in patients post-surgery, highlighting the need for targeted preventive strategies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Changes in Urine Composition and Risk of Kidney Stone Disease Following Bariatric Surgery: A Systematic Review over Last 2 Decades. Gadiyar, N., Geraghty, RM., Premakumar, Y., et al.[2022]

Both very low-calorie diets (VLCD 240 and VLCD 420) resulted in significant weight loss in obese patients, with VLCD 240 achieving an average loss of 8.9 kg/month and VLCD 420 achieving 7.6 kg/month over 1-2 months.

The VLCD 420 diet showed a quicker recovery in nitrogen balance compared to VLCD 240, indicating better metabolic stability, as the nitrogen balance for VLCD 240 remained negative throughout the treatment period.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The efficacy and metabolic effects of two different regimens of very low calorie diet. Ohno, M., Miura, J., Arai, K., et al.[2014]

Dietary counseling is crucial for preventing kidney stones, particularly calcium oxalate stones, which are the most common type, and should focus on modifiable dietary factors.

Individuals with a history of calcium-containing kidney stones should maintain adequate fluid intake (at least 2 liters of urine per day) and not restrict calcium intake, as a minimum of 800 mg/day is recommended to prevent negative health effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary factors and kidney stone formation. Curhan, GC., Curhan, SG.[2013]

References

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

Patient-centered medical therapy for nephrolithiasis. [2013]

2. Brazil pubmed.ncbi.nlm.nih.gov

Influence of clinical therapy and nutritional counseling on the recurrence of urolithiasis. [2019]

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

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

4. Brazil pubmed.ncbi.nlm.nih.gov

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones. [2022]

5. Serbia pubmed.ncbi.nlm.nih.gov

[Treatment of extreme obesity with a very low calorie diet]. [2009]

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

Use of a Very Low Calorie Diet for Weight Loss in a Patient with Acute Kidney Injury and Class III Obesity: A Case Study. [2023]

8. England pubmed.ncbi.nlm.nih.gov

Risk of symptomatic gallstones and cholecystectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study. [2021]

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

Kidney stone risk following modern bariatric surgery. [2021]

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

Changes in Urine Composition and Risk of Kidney Stone Disease Following Bariatric Surgery: A Systematic Review over Last 2 Decades. [2022]

11. England pubmed.ncbi.nlm.nih.gov

The efficacy and metabolic effects of two different regimens of very low calorie diet. [2014]

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

Dietary factors and kidney stone formation. [2013]