The relationship between kidney function and body mass index before and after bariatric surgery in patients with chronic kidney disease

Long-term systemic effects of metabolic bariatric surgery: A multidisciplinary perspective

Background

Obesity is a global health crisis with profound implications on various body systems, contributing to a series of comorbidities. Metabolic Bariatric Surgery (MBS) has emerged as an effective treatment option for severe obesity, with significant weight reduction and potential systemic physiological alterations.

Objectives

This narrative review aims to provide a comprehensive analysis of the long-term effects of MBS on a wide array of body systems, including the heart, liver, kidneys, reproductive system, skin, lungs, digestive tract, pancreas, and blood, as well as related cancers of these organs.

Methods

A systematic search was conducted in academic databases (PubMed, ISI Web of Science, and Scopus) for observational studies and reviews published between July 2000 and December 2023, investigating the association between MBS and the subsequent function of different organ systems. High-quality studies were prioritized to ensure reliable evidence synthesis.

Results

MBS has demonstrated favorable outcomes in reducing cardiovascular disease risk, improving cardiac function, and alleviating heart failure symptoms. It has also been associated with improved respiratory function, remission of obstructive sleep apnea, and reduced cancer incidence and mortality. Additionally, MBS has shown benefits in managing gastrointestinal disorders, enhancing glycemic control, and promoting pancreatic beta-cell regeneration in type 2 diabetes mellitus. However, some methods of MBS are associated with a higher risk of cholelithiasis, GERD, and pancreatic exocrine insufficiency.

Conclusion

MBS has far-reaching systemic effects beyond weight loss, offering potential long-term benefits for various organ systems and comorbidities associated with obesity. For many patients with severe obesity, the potential benefits of Metabolic and Bariatric Surgery (MBS) can outweigh the associated risks. However, careful evaluation by a qualified healthcare professional is crucial to determine candidacy and ensure a successful outcome. Further research is needed to fully elucidate the long-term impacts and tailor personalized treatment approaches.

Anti-obesity pharmacotherapy in adults with chronic kidney disease

Obesity is a leading risk factor for the development and progression of kidney disease and a major barrier to optimal management of patients with chronic kidney disease. While in the past anti-obesity drugs offered only modest weight loss efficacy in exchange for various safety and tolerability risks, a wave of safer, more tolerable, and more effective treatment options is transforming the management of obesity. This review evaluates current and future pharmacologic anti-obesity therapy in adults through a kidney-oriented lens. It also explores the goals of anti-obesity treatment, describes the underlying putative mechanisms of action, and raises important scientific questions that deserve further exploration in people with chronic kidney disease.

A 5-year propensity-matched analysis of perioperative outcomes in patients with chronic kidney disease undergoing bariatric surgery

BACKGROUND

Bariatric surgery can improve renal function in patients with comorbid chronic kidney disease (CKD) and obesity. Additionally, bariatric surgery can enhance outcomes following renal transplantation. The safety of bariatric surgery in patients with CKD has been debated in the literature. This study evaluates the frequency of perioperative complications associated with CKD.

METHODS

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was queried from 2015-2019. Patients were included if they had a vertical sleeve gastrectomy (VSG) or Roux-en-Y gastric bypass (RYGB) and were stratified based on CKD status. An unmatched and propensity-matched analysis was performed comparing 30-day perioperative outcomes between the groups.

RESULTS

A total of 717,809 patients included in this study, 5817(0.8%) had CKD, of whom 2266(0.3%) were on dialysis. 74.3% of patients with CKD underwent VSG with 25.7% underwent RYGB. Comparing RYGB to VSG, patients who underwent RYGB had a higher rate of deep organ space infection (0.7%vs.0.1%,p = 0.021) and re-intervention (5.0% vs. 2.2%,p < 0.001). Within the VSG cohort, a matched analysis was performed for those with CKD and without CKD. The CKD cohort had higher risk of complications such as bleeding (2.1%vs. 0.9%,p < 0.001), readmission (9.3%vs.4.9%,p < 0.001), reoperation (2.7%vs.1.3%,p < 0.001), and need for reintervention (2.2%vs.1.3%,p < 0.001). Notably, patients with CKD also had a higher mortality (0.6%vs.0.2%,p = 0.003). No difference was seen between patients with renal insufficiency and patients on dialysis.

CONCLUSION

VSG has been the operation of choice in patients with CKD. Our results showed it is the safer option for patients with CKD compared to RYGB. Although this patient population does have an increased risk of adverse perioperative events, dialysis didn't affect the outcome. Bariatric surgeons who operate on patients with CKD should be well informed and remain vigilant given the increased perioperative risk. The risk is still considerably low, and the potential benefit on renal function and improvement in candidacy for renal transplant outweigh the risk. They should be considered as surgical candidates.

Obesity and renal disease: Benefits of bariatric surgery

The prevalence of obesity, a preventable and reversible condition with a high impact on health, continues to rise, especially after the COVID-19 pandemic. Severe overweight is well recognized as a risk factor for diabetes and hypertension, among other conditions, that may increase cardiovascular risk. Obesity has grown simultaneously with a rise in the prevalence of chronic kidney disease, and a pathophysiological link has been established, which explains its role in generating the conditions to facilitate the emergence and maximize the impact of the risk factors of chronic kidney disease and its progression to more advanced stages. Knowing the mechanisms involved and having different tools to reverse the overweight and its consequences, bariatric surgery has arisen as a useful and efficient method, complementary or alternative to others, such as lifestyle changes and/or pharmacotherapy. In a detailed review, the mechanisms involved in the renal consequences of obesity, the impact on risk factors, and the potential benefit of bariatric surgery at different stages of the disease and its progression are exposed and analyzed. Although the observational evidence supports the value of bariatric surgery as a renoprotective measure in individuals with obesity, diabetic or not, randomized studies are expected to establish evidence-based recommendations that demonstrate its positive risk-benefit balance as a complementary or alternative therapeutic tool.

Obesity and chronic kidney disease

The prevalence of obesity has increased dramatically during the past decades, which has been a major health problem. Since 1975, the number of people with obesity worldwide has nearly tripled. An increasing number of studies find obesity as a driver of chronic kidney disease (CKD) progression, and the mechanisms are complex and include hemodynamic changes, inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system (RAAS). Obesity-related kidney disease is characterized by glomerulomegaly, which is often accompanied by localized and segmental glomerulosclerosis lesions. In these patients, the early symptoms are atypical, with microproteinuria being the main clinical manifestation and nephrotic syndrome being rare. Weight loss and RAAS blockers have a protective effect on obesity-related CKD, but even so, a significant proportion of patients eventually progress to end-stage renal disease despite treatment. Thus, it is critical to comprehend the mechanisms underlying obesity-related CKD to create new tactics for slowing or stopping disease progression. In this review, we summarize current knowledge on the mechanisms of obesity-related kidney disease, its pathological changes, and future perspectives on its treatment.

Obstacles and opportunities in managing coexisting obesity and CKD: Report of a scientific workshop cosponsored by the National Kidney Foundation and The Obesity Society

The National Kidney Foundation (NKF) and The Obesity Society (TOS) cosponsored a multispecialty international workshop in April 2021 to advance the understanding and management of obesity in adults with chronic kidney disease (CKD). The underlying rationale for the workshop was the accumulating evidence that obesity is a major contributor to CKD and adverse outcomes in individuals with CKD, and that effective treatment of obesity, including lifestyle intervention, weight loss medications, and metabolic surgery, can have beneficial effects. The attendees included a range of experts in the areas of kidney disease, obesity medicine, endocrinology, diabetes, bariatric/metabolic surgery, endoscopy, transplant surgery, and nutrition, as well as patients with obesity and CKD. The group identified strategies to increase patient and provider engagement in obesity management, outlined a collaborative action plan to engage nephrologists and obesity medicine experts in obesity management, and identified research opportunities to address gaps in knowledge about the interaction between obesity and kidney disease. The workshop's conclusions help lay the groundwork for development of an effective, scientifically based, and multidisciplinary approach to the management of obesity in people with CKD.

Obstacles and Opportunities in Managing Coexisting Obesity and CKD: Report of a Scientific Workshop Cosponsored by the National Kidney Foundation and The Obesity Society

The National Kidney Foundation (NKF) and The Obesity Society (TOS) cosponsored a multispecialty international workshop in April 2021 to advance the understanding and management of obesity in adults with chronic kidney disease (CKD). The underlying rationale for the workshop was the accumulating evidence that obesity is a major contributor to CKD and adverse outcomes in individuals with CKD, and that effective treatment of obesity, including lifestyle intervention, weight loss medications, and metabolic surgery, can have beneficial effects. The attendees included a range of experts in the areas of kidney disease, obesity medicine, endocrinology, diabetes, bariatric/metabolic surgery, endoscopy, transplant surgery, and nutrition, as well as patients with obesity and CKD. The group identified strategies to increase patient and provider engagement in obesity management, outlined a collaborative action plan to engage nephrologists and obesity medicine experts in obesity management, and identified research opportunities to address gaps in knowledge about the interaction between obesity and kidney disease. The workshop's conclusions help lay the groundwork for development of an effective, scientifically based, and multidisciplinary approach to the management of obesity in people with CKD.

Anything New in the Treatment of Obesity in Obese Patients with CKD?

Treatment for obesity in patients with CKD englobes a wide range of options, from lifestyle modification to bariatric surgery. Weight loss improves metabolic parameters and stimulates changes in renal function that lead to improvement of glomerular hyperfiltration. The most common clinical presentation is a slowly increasing non-nephrotic proteinuria that is followed by a progressive decline of kidney function. The use of multitarget therapies, with appropriate dietary education, emerging diets, the use of new RAAS blocking agents, the combination of iSGLT2 or GLP-1 agonists, as well as bariatric surgery, may play a key role in finally achieving the desired nephroprotection in this CKD population. New therapeutic agents and novel biomarkers, such as adipocyte cytokines, are needed to monitor and mitigate progression to end-stage renal disease. The emerging "lipidomics" and the role of nonalcoholic fatty liver are relevant research lines.

Management of Obesity in Adults with CKD

Obesity is a leading public health problem that currently affects over 650 million individuals worldwide. Although interest in the adverse effects of obesity has grown exponentially in recent years, less attention has been given to studying its management in individuals with CKD. This relatively unexplored area should be considered a high priority because of the rapid growth and high prevalence of obesity in the CKD population, its broad impact on health and outcomes, and its modifiable nature. This article begins to lay the groundwork in this field by providing a comprehensive overview that critically evaluates the available evidence related to obesity and kidney disease, identifies important gaps in our knowledge base, and integrates recent insights in the pathophysiology of obesity to help provide a way forward in establishing guidelines as a basis for managing obesity in CKD. Finally, the article includes a kidney-centric algorithm for management of obesity that can be used in clinical practice.

Comparison of eGFR formulas in determining chronic kidney disease stage in bariatric patients and the impact on perioperative outcomes

BACKGROUND

Chronic kidney disease (CKD) independently increases the risk of 30-day adverse outcomes following metabolic and bariatric surgery (MBS). However, no studies have evaluated the stage of CKD at which increased perioperative risk is manifested. Here, we correlate 30-day major morbidities after MBS with extent of renal disease based on CKD Stage.

OBJECTIVES

To determine the impact of CKD stage on perioperative outcomes after bariatric surgery.

SETTING

Academic Hospital.

METHODS

From the 2017 Metabolic and Bariatric Surgery Quality Improvement Program (MBSAQIP) database, we identified patients with CKD who underwent sleeve gastrectomy or laparoscopic gastric bypass surgery. Glomerular filtration rates (GFRs) were calculated and cohorts were generated based on CKD Stage. Complication rates and rates of morbidity and mortality were compared between stages, and strengths of correlation were calculated.

RESULTS

GFR and CKD Stage were calculated for 150,283 patients. There was a significant increase in the risk of major morbidity at each progressive stage of CKD (P < .001 for all compared stages). There was a strong positive linear correlation between increasing CKD Stage and total morbidity (r² = .983), including reoperation ( r² = .784), readmission (r² = .936), unplanned ICU transfer (r² = .853), and aggregate complications such as pulmonary (r² = .900), bleeding (r² = .878), or progressive worsening of renal function (r² = .845). In logistic regression, for every 10-point decrease in GFR, odds of total morbidity increased by 6%.

CONCLUSION

An increased risk of perioperative complications may be seen in early stages of CKD, and risk is compounded in more advanced stages. Bariatric surgical candidates should be counseled on their increased risk of surgical complications even with mild CKD, and the benefits of bariatric surgery should be carefully weighed against significantly increased risks of complications in severe CKD.