Roux-en-Y gastric bypass is an effective bridge to kidney transplantation: Results from a single center

Obesity and Kidney Transplantation-How to Evaluate, What to Do, and Outcomes

Obesity is a growing issue that is spreading worldwide; its prevalence is ever increasing in patients with end-stage renal disease and represents a potential barrier to transplantation. The lack of unanimous guidelines exacerbates the current disparity in treatment, which can affect outcomes, leading to a significantly longer time on the waiting list. Multidisciplinary and multimodal management (encompassing several healthcare professionals such as nephrologists, transplant physicians and surgeons, primary care providers, and nurses) is of paramount importance for the optimal management of this patient population in a continuum from waitlisting to transplantation. Development of this guideline followed a standardized protocol for evidence review. In this review, we report on our clinical experience in transplantation of obese patients; strategies to manage this condition, including bariatric surgery, suitable timing for transplantation among this patient population, and clinical experience in robotic sleeve gastrectomy; and simultaneous robotic kidney transplantation to achieve optimal outcomes.

Bariatric surgery in patients with obesity and end-stage renal disease

BACKGROUND

Bariatric surgery has been suggested as a treatment for obesity and end-stage renal disease (ESRD). Although the number of bariatric surgeries in patients with ESRD is increasing, its safety and effectiveness in these patients are still controversial and the surgical method of choice in these patients is under debate.

OBJECTIVES

To compare the outcomes of bariatric surgery between patients with and without ESRD and to assess different methods of bariatric surgery in patients with ESRD.

SETTING

Meta-analysis.

METHODS

A comprehensive search was conducted in Web of Science and Medline (via Pubmed) until May 2022. Tow meta-analyses were performed: A) to compare bariatric surgery outcomes among patients with and without ESRD, and B) to compare outcomes of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) in patients with ESRD. Using a random-effect model, odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were computed for surgical and weight loss outcomes.

RESULTS

Of 5895 articles, 6 studies were included in meta-analysis A and 8 studies in meta-analysis B. The risk of bias was moderate to serious among studies. Major postoperative complications (OR = 2.82; 95% CI = 1.66-4.77; P = .0001), reoperation (OR = 2.66; 95% CI = 1.99-3.56; P < .00001), readmission (OR = 2.37; 95% CI = 1.55-3.64; P < .0001), and in-hospital/90-d mortality (OR = 4.03; 95% CI = 1.80-9.03; P = .0007) were higher in patients with ESRD. Patients with ESRD also had a longer hospital stay (MD = 1.23; 95% CI = .32-2.14; P = .008). Bleeding, leakage, and total weight loss were comparable among groups. SG showed a 10% lower rate of overall complications and significantly shorter hospital stay than RYGB did. The quality of evidence was very low for the outcomes CONCLUSIONS: Bariatric surgery in patients with ESRD seems to have higher rates of major complications and perioperative mortality than in patients without ESRD, but a comparable rate of overall complications. SG has fewer postoperative complications and could be the method of choice in these patients. These findings should be interpreted cautiously in light of the moderate to high risk of bias in most included studies.

Bariatric surgery improves access to renal transplantation and is safe in renal failure as well as after transplantation: A systematic review and meta-analysis

INTRODUCTION

Effective workup and listing of end-stage renal disease (ESRD) patients for renal transplantation, often with multiple co-morbidities, poses a challenge for transplant teams. Obesity is a common co-morbidity associated with adverse outcomes in ESRD and kidney transplant (KT) recipients. Bariatric and metabolic surgery (BMS) has long been established as a safe and effective treatment for morbid obesity. In this study, the authors aimed to evaluate the strength of evidence for both the efficacy and safety of bariatric surgery in patients with ESRD or kidney transplantation.

METHODS

A literature search was performed using key terms including "transplantation", "kidney", "renal", "obesity", and "bariatric". Databases searched include MEDLINE, EMBASE and Web of Science from inception to date (April 2021). Methodological quality was assessed using the Newcastle-Ottawa tool. Selected articles were then categorised into patients awaiting waiting list acceptance, patients awaiting transplantation, patients undergoing simultaneous BMS + KT and patients undergoing BMS following a previous renal transplant. Summary effects are presented with a level of statistical significance and 95% Confidence Intervals.

RESULTS

A total of 28 articles were selected following the literature search. Fourteen studies on patients awaiting listing (n = 1903), nine on patients on the KT waiting list (n = 196), a single study on simultaneous BMS and KT and ten studies on patients undergoing BMS following KT (n = 198). Mean change in BMI for patients awaiting listing was -11.3 kg/m² (95%CI: -15.3 to -7.3, p < 0.001), mean change in BMI for patients listed for KT was -11.2 kg/m 2(95%CI: -12.9 to -9.5, p 0.001) and mean change for patients with prior KT was -11.0 kg/m² (95%CI: -7.09 to -14.9, p < 0.001). The combined mortality rate for patients who had undergone both BMS and KT was 4% (n = 15).

DISCUSSION

This review demonstrates BMS is both safe and efficacious in patients with ESRD prior to KT and in those post KT. It would enable difficult-to-list obese recipients the possibility to undergo transplantation and should be considered as part of the work up process.

Comparison of Kidney Transplantation Outcomes Between Patients with and Without Pre-transplantation Bariatric Surgery: a Systematic Review

This systematic review evaluated the impact of bariatric surgery, performed to improve eligibility for kidney transplantation, on post-transplantation outcomes. A systematic literature search was performed for articles published by 30 January 2022. A total of 31 studies were included. Among patients without pre-transplantation bariatric surgery, 18 studies reported 13.7% graft loss and 9.1% mortality within 5 years' post-transplantation. Among recipients with pre-transplantation bariatric surgery, 15 studies reported 8.7% graft loss and 2.8% mortality within 1 month to over 5 years' post-transplantation. Two case-control studies comparing post-transplantation outcomes between recipients with and without prior bariatric surgery demonstrated no significant differences between groups for graft loss, patient mortality, delayed graft function, wound complications and lymphocele. Non-randomized selection of patients and different lengths of follow-up limit the results of this study.

The application of body mass index-based eligibility criteria may represent an unjustified barrier to renal transplantation in people with obesity

The prevalence of both obesity and end-stage kidney disease is increasing. In many centres, obesity is considered a relative contraindication to kidney transplantation due to an association with short- and longer-term adverse outcomes. This leads to delayed transplant waitlisting and longer organ waiting times for people with obesity. This review evaluates whether intentional pre-transplant weight loss in people with obesity improves kidney transplant outcomes. There are currently no data showing that non-surgical weight loss of 10% or more improves graft or patient survival over 4-5 years. Outcomes from bariatric surgery cohorts have been generally neutral or favourable after pre-transplant weight loss of ~25%. Given the survival benefit of kidney transplantation compared to maintenance dialysis, and the difficulty of achieving and maintaining weight loss, the common practice of recommending weight loss to achieve arbitrary targets prior to waiting list activation needs to be carefully considered.

Management of obesity in kidney transplant candidates and recipients: A clinical practice guideline by the Descartes working group of ERA

The clinical practice guideline Management of Obesity in Kidney Transplant Candidates and Recipients was developed to guide decision-making in caring for people with end-stage kidney disease (ESKD) living with obesity. The document considers the challenges in defining obesity, weighs interventions for treating obesity in kidney transplant candidates as well as recipients and reflects on the impact of obesity on the likelihood of wait-listing as well as its effect on transplant outcomes. It was designed to inform management decisions related to this topic and provide the backdrop for shared decision-making. This guideline was developed by the European Renal Association’s Developing Education Science and Care for Renal Transplantation in European States working group. The group was supplemented with selected methodologists to supervise the project and provide methodological expertise in guideline development throughout the process. The guideline targets any healthcare professional treating or caring for people with ESKD being considered for kidney transplantation or having received a donor kidney. This includes nephrologists, transplant physicians, transplant surgeons, general practitioners, dialysis and transplant nurses. Development of this guideline followed an explicit process of evidence review. Treatment approaches and guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence and the strength of recommendations followed the Grading of Recommendations Assessment, Development and Evaluation approach. Limitations of the evidence are discussed and areas of future research are presented.

Postoperative outcomes after bariatric surgery in patients on chronic dialysis: A systematic review and meta-analysis

BACKGROUND

Obesity is a barrier to kidney transplantation for patients with kidney failure. Consequently, bariatric surgery is often considered as a bridge to transplantation, even though its risks and benefits are poorly characterised in the dialysis population.

METHODS

Systematic searches of observational studies indexed in Embase, MEDLINE and CENTRAL till April 2020 were performed to identify relevant studies. Risk of bias was assessed by the Newcastle Ottawa Scale and quality of evidence was summarised in accordance with GRADE methodology. Random effects meta-analyses were performed to obtain summary odds ratios for postoperative outcomes.

RESULTS

Four cohort studies involving 4196 chronic dialysis and 732,204 non-dialysis patients undergoing bariatric surgery were included. Sleeve gastrectomy (61%), and Roux-en-Y gastric bypass (29%) were the most common procedures performed. Absolute rates of adverse events were low, but the odds of postoperative mortality (0.4-0.5% vs. 0.1%; odds ratio [OR] 4.7, 95%CI 2.2-9.9), and myocardial infarction (0.0-0.5% vs. 0.1%, OR 3.4, 95% CI 2.0-5.9) were higher in dialysis compared to non-dialysis patients. Patients on dialysis also had more than 2-fold increased odds of returning to theatre and having a readmission. Rates of kidney transplant wait-listing among dialysis patients was 59%, with 28% of all patients eventually receiving a kidney transplant.

CONCLUSION

Patients receiving chronic dialysis have substantially increased odds of postoperative mortality and myocardial infarction following bariatric surgery compared with patient who do not have kidney failure. It is uncertain whether bariatric surgery improves the likelihood of kidney transplantation, with mid- to long-term outcomes being poorly described.

Successful surgical weight loss with laparoscopic sleeve gastrectomy for morbid obesity prior to kidney transplantation

Morbid obesity in kidney transplant (KT) candidates is associated with increased complications and graft failure. Multiple series have demonstrated rapid and significant weight loss after laparoscopic sleeve gastrectomy (LSG) in this population. Long-term and post-transplant weight evolutions are still largely unknown. A retrospective review was performed in eighty patients with end-stage kidney disease (ESKD) who underwent LSG in preparation for KT. From a median initial BMI of 43.7 kg/m² , the median change at 1-year was -10.0 kg/m² . Successful surgical weight loss (achieving a BMI < 35 kg/m² or an excess body weight loss >50%) was attained in 76.3% and was associated with male gender, predialysis status, lower obesity class and lack of coronary artery disease. Thirty-one patients subsequently received a KT with a median delay of 16.7 months. Weight regain (increase in BMI of 5 kg/m² postnadir) and recurrent obesity (weight regain + BMI > 35) remain a concern, occurring post-KT in 35.7% and 17.9%, respectively. Early LSG should be considered for morbidly obese patients with ESKD for improved weight loss outcomes. Early KT after LSG does not appear to affect short-term surgical weight loss. Candidates with a BMI of up to 45 kg/m² can have a reasonable expectation to achieve the limit within 1 year.

Effectiveness and Safety of Bariatric Surgery in Patients with End-Stage Chronic Kidney Disease or Kidney Transplant

OBJECTIVE

This study aimed to evaluate (1) the effectiveness, complications, and postoperative access to transplantation in end-stage chronic kidney disease (ECKD) and (2) the effectiveness and complications of bariatric surgery in patients who had already undergone kidney transplant.

METHODS

A systematic review and meta-analysis of mortality and complications rates were performed. Thirty studies were reviewed.

RESULTS

After bariatric surgery, patients with ECKD had similar postoperative weight loss to patients from the general population. Meta-analysis showed post-bariatric surgery rates of 2% (95% CI: 0%-3%) for mortality and 7% (95% CI: 2%-14%) for complications. Approximately one-fifth of the patients had access to a transplant. This rate may be underestimated because of the short duration of follow-up. The lack of control groups did not allow for a conclusion on the role of bariatric surgery in facilitating access to kidney transplantation. In patients who had received a kidney transplant, bariatric surgery seemed to improve renal function but increased graft-rejection risk, possibly because of changes in the bioavailability of immunosuppressant drugs.

CONCLUSIONS

Bariatric surgery yields significant weight loss in patients with ECKD that improves patients' chances of accessing a transplant but does not guarantee it; however, the risk for complications and death is higher than in other patients. After transplantation, bariatric surgery-induced weight loss appeared to positively impact the function of the grafted kidney, but careful monitoring of immunosuppressant medications is required.

Impaired dexamethasone resorption in two patients with pseudo-Cushing after bariatric surgery: Implications for immunosuppressive treatment

Two cases of middle-aged female patients treated by gastric bypass surgery for weight loss presented to our clinic for a follow-up examination 3-6 months after the surgical procedure (a mini gastric bypass and a modified single anastomosis sleeve-ileostomy). In both patients increased ACTH levels and either high serum cortisol or an increased urinary cortisol excretion was apparent and triggered further endocrine testing. Serum cortisol could not be suppressed adequately by 2 and 4 mg dexamethasone in the standardized oral overnight suppression test while midnight salivary cortisol dropped well below the desired cut-off. This led to the hypothesis of an impaired dexamethasone resorption and could be further substantiated by suppression of serum cortisol below the cut-off by an intravenous dexamethasone application. The data presented point to an impairment of enteral synthetic corticosteroid resorption in patients after gastric bypass surgery and could be of importance for individuals in need for immunosuppressive treatment. In view of the growing number of bariatric procedures, pharmacokinetics of corticosteroids and other drugs should be tested in clinical trials.

Bariatric surgery to achieve transplant in end-stage organ disease patients: A systematic review and meta-analysis

BACKGROUND

As obesity prevalence grows, more end-stage organ disease patients will be precluded from transplant. Numerous reports suggest bariatric surgery in end-stage organ disease may help patients achieve weight loss sufficient for transplant listing.

METHODS

We performed a systematic review/meta-analysis of studies of bariatric surgery to achieve solid organ transplant listing.

RESULTS

Among 82 heart failure patients, 40.2% lost sufficient weight for listing, 29.3% were transplanted, and 8.5% had sufficient improvement with weight loss they no longer required transplantation. Among 28 end-stage lung disease patients, 28.6% lost sufficient weight for listing, 7.1% were transplanted, and 14.3% had sufficient improvement following weight loss they no longer required transplant. Among 41 cirrhosis patients, 58.5% lost sufficient weight for listing, 41.5% were transplanted, and 21.9% had sufficient improvement following weight loss they no longer required transplant. Among 288 end-stage/chronic kidney disease patients, 50.3% lost sufficient weight for listing and 29.5% were transplanted.

CONCLUSIONS

Small sample size and publication bias are limitations; however, bariatric surgery may benefit select end-stage organ disease patients with obesity that precludes transplant candidacy.

Management of metabolic alterations in adult kidney transplant recipients: A joint position statement of the Italian Society of Nephrology (SIN), the Italian Society for Organ Transplantation (SITO) and the Italian Diabetes Society (SID)

Chronic metabolic alterations such as post-transplant diabetes mellitus (PTDM), dyslipidaemias and overweight/obesity significantly impact on kidney transplant (KT) outcomes. This joint position statement is based on the evidence on the management of metabolic alterations in KT recipients (KTRs) published after the release of the 2009 KDIGO clinical practice guideline for the care of KTRs. Members of the Italian Society of Nephrology (SIN), the Italian Society for Organ Transplantation (SITO) and the Italian Diabetes Society (SID) selected to represent professionals involved in the management of KTRs undertook a systematic review of the published evidence for the management of PTDM, dyslipidaemias and obesity in this setting. The aim of this work is to provide an updated review of the evidence on the prevention, diagnosis and treatment of metabolic alterations in KTRs, in order to support physicians, patients and the Healthcare System in the decision-making process when choosing among the various available options.

Metabolic Disorders with Kidney Transplant

Metabolic disorders are highly prevalent in kidney transplant candidates and recipients and can adversely affect post-transplant graft outcomes. Management of diabetes, hyperparathyroidism, and obesity presents distinct opportunities to optimize patients both before and after transplant as well as the ability to track objective data over time to assess a patient's ability to partner effectively with the health care team and adhere to complex treatment regimens. Optimization of these particular disorders can most dramatically decrease the risk of surgical and cardiovascular complications post-transplant. Approximately 60% of nondiabetic patients experience hyperglycemia in the immediate post-transplant phase. Multiple risk factors have been identified related to development of new onset diabetes after transplant, and it is estimated that upward of 7%-30% of patients will develop new onset diabetes within the first year post-transplant. There are a number of medications studied in the kidney transplant population for diabetes management, and recent data and the risks and benefits of each regimen should be optimized. Secondary hyperparathyroidism occurs in most patients with CKD and can persist after kidney transplant in up to 66% of patients, despite an initial decrease in parathyroid hormone levels. Parathyroidectomy and medical management are the options for treatment of secondary hyperparathyroidism, but there is no randomized, controlled trial providing clear recommendations for optimal management, and patient-specific factors should be considered. Obesity is the most common metabolic disorder affecting the transplant population in both the pre- and post-transplant phases of care. Not only does obesity have associations and interactions with comorbid illnesses, such as diabetes, dyslipidemia, and cardiovascular disease, all of which increase morbidity and mortality post-transplant, but it also is intimately inter-related with access to transplantation for patients with kidney failure. We review these metabolic disorders and their management, including data in patients with kidney transplants.

Bariatric Surgery Is Efficacious and Improves Access to Transplantation for Morbidly Obese Renal Transplant Candidates

BACKGROUND

The surgical risk of morbidly obese patients is high and even higher for kidney transplant candidates. A BMI > 35-40 kg/m² is often a contraindication for that surgery. The safety, feasibility, and outcome of bariatric surgery for those patients are inconclusive.

METHODS

We conducted a retrospective chart review of prospectively collected data on morbidly obese renal transplant candidates who underwent laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Y gastric bypass (LRYGB) in our institution between January 2009 and September 2017. The reported outcome included body weight and graft status after a mean follow-up of 47 months (range 0.5-5 years).

RESULTS

Twenty-four patients (8 females, 16 males, average age 54 years, average preoperative BMI 41 kg/m² [range 35-51]) underwent LSG (n = 17) or LRYGB (n = 7). Sixteen of them (67%) proceeded to kidney transplantation. Of the 8 pre-transplant and post-bariatric surgery patients, 5 are on the waitlist, and 2 patients died (one of staple line leakage, and one from sepsis unrelated to the bariatric surgery). The average time from bariatric surgery to transplantation was 1.5 years (range 1 month to 4.3 years). The average pre-transplantation BMI was 28 kg/m² (range 19-36). The mean percentage of excess weight loss was 66% (n = 21), and the total percentage of weight loss was 29% (n = 21). Comorbidities (type 2 diabetes, hypertension, and dyslipidemia) improved significantly following both surgical approaches.

CONCLUSIONS

LSG and LRYGB appear to effectively address obesity issues before kidney transplantation and improve surgical access. Morbidly obese transplant candidates would benefit from prior bariatric surgery.

Metabolic Surgery to Treat Obesity in Diabetic Kidney Disease, Chronic Kidney Disease, and End-Stage Kidney Disease; What Are the Unanswered Questions?

Obesity is a major factor in contemporary clinical practice in nephrology. Obesity accelerates the progression of both diabetic and non-diabetic chronic kidney disease and, in renal transplantation, both recipient and donor obesity increase the risk of allograft complications. Obesity is thus a major driver of renal disease progression and a barrier to deceased and living donor kidney transplantation. Large observational studies have highlighted that metabolic surgery reduces the incidence of albuminuria, slows chronic kidney disease progression, and reduces the incidence of end-stage kidney disease over extended follow-up in people with and without type 2 diabetes. The surgical treatment of obesity and its metabolic sequelae has therefore the potential to improve management of diabetic and non-diabetic chronic kidney disease and aid in the slowing of renal decline toward end-stage kidney disease. In the context of patients with end-stage kidney disease, although complications of metabolic surgery are higher, absolute event rates are low and it remains a safe intervention in this population. Pre-transplant metabolic surgery increases access to kidney transplantation in people with obesity and end-stage kidney disease. Metabolic surgery also improves management of metabolic complications post-kidney transplantation, including new-onset diabetes. Procedure selection may be critical to mitigate the risks of oxalate nephropathy and disruption to immunosuppressant pharmacokinetics. Metabolic surgery may also have a role in the treatment of donor obesity, which could increase the living kidney donor pool with potential downstream impact on kidney paired exchange programmes. The present paper provides a comprehensive coverage of the literature concerning renal outcomes in clinical studies of metabolic surgery and integrates findings from relevant mechanistic pre-clinical studies. In so doing the key unanswered questions for the field are brought to the fore for discussion.

Obesity and bariatric intervention in patients with chronic renal disease

Obesity is associated with chronic metabolic conditions that directly and indirectly cause kidney parenchymal damage. A review of the literature was conducted to explore existing evidence of the relationship between obesity and chronic kidney disease as well as the role of bariatric surgery in improving access to kidney transplantation for patients with a high body mass index. The review showed no definitive evidence to support the use of a transplant eligibility cut-off parameter based solely on the body mass index. Moreover, in the pre-transplant scenario, the obesity paradox is associated with better patient survival among obese than non-obese patients, although promising results of bariatric surgery are emerging. However, until more information regarding improvement in outcomes for obese kidney transplant candidates is available, clinicians should focus on screening of the overall frailty condition of transplant candidates to ensure their eligibility and addition to the wait list.

Non-immunological complications following kidney transplantation

Kidney transplantation (KT) is the most effective way to decrease the high morbidity and mortality of patients with end-stage renal disease. However, KT does not completely reverse the damage done by years of decreased kidney function and dialysis. Furthermore, new offending agents (in particular, immunosuppression) added in the post-transplant period increase the risk of complications. Cardiovascular (CV) disease, the leading cause of death in KT recipients, warrants pre-transplant screening based on risk factors. Nevertheless, the screening methods currently used have many shortcomings and a perfect screening modality does not exist. Risk factor modification in the pre- and post-transplant periods is of paramount importance to decrease the rate of CV complications post-transplant, either by lifestyle modification (for example, diet, exercise, and smoking cessation) or by pharmacological means (for example, statins, anti-hyperglycemics, and so on). Post-transplantation diabetes mellitus (PTDM) is a major contributor to mortality in this patient population. Although tacrolimus is a major contributor to PTDM development, changes in immunosuppression are limited by the higher risk of rejection with other agents. Immunosuppression has also been implicated in higher risk of malignancy; therefore, proper cancer screening is needed. Cancer immunotherapy is drastically changing the way certain types of cancer are treated in the general population; however, its use post-transplant is limited by the risk of allograft rejection. As expected, higher risk of infections is also encountered in transplant recipients. When caring for KT recipients, special attention is needed in screening methods, preventive measures, and treatment of infection with BK virus and cytomegalovirus. Hepatitis C virus infection is common in transplant candidates and in the deceased donor pool; however, newly developed direct-acting antivirals have been proven safe and effective in the pre- and post-transplant periods. The most important and recent developments on complications following KT are reviewed in this article.

Preventive Nephrology: The Role of Obesity in Different Stages of Chronic Kidney Disease

BACKGROUND

Obesity is increasing worldwide and has become a nontraditional risk factor in chronic kidney disease (CKD).

SUMMARY

Obesity-related nephropathy may aggravate renal complications of the metabolic syndrome and progress to advanced CKD stages, while obesity in early stages of CKD is clearly related to the development of kidney disease. A high body mass index (BMI) in advanced CKD stages and dialysis is an advantage for survival (so called "obesity paradox"). A high lean body to fat mass index indicates a beneficial state of body composition. In contrast, loss of muscle mass with increasing fat mass causes "sarcopenia obesity," which is related to unfavorable outcomes in renal replacement therapy. Obesity (BMI > 30-35) in renal transplant recipients is associated with a higher risk of complications such as delayed graft function, increased rates of rejection, and graft loss. While conservative management of morbid obesity is failing in most cases, bariatric surgery seems to be an option in some cases to improve renal complications in the early stage of CKD or in transplant candidates.

KEY MESSAGE

In conclusion, obesity is increasingly prevalent among CKD patients. Adequate management with respect to the specific role of obesity in different stages of CKD should be integrated in routine renal care.