Recovery of Renal Function in a Dialysis-Dependent Patient Following Gastric Bypass Surgery

Bariatric surgery prior to transplantation and risk of early hospital re-admission, graft failure, or death following kidney transplantation

Bariatric surgery has been shown to be safe in the dialysis population. Whether bariatric surgery before kidney transplantation influences posttransplant outcomes has not been examined nationally. We included severely obese (BMI >35) dialysis patients between 18 and 70 years who received a kidney transplant according to the US Renal Data System. We determined the association between history of bariatric surgery and risk of 30-day readmission, graft failure, or death after transplantation using multivariable logistic, Fine-Gray, and Cox models. We included 12 573 patients, of whom 503 (4%) received bariatric surgery before transplantation. Median age at transplant was 53 years; 42% were women. Overall, history of bariatric surgery was not statistically significantly associated with graft failure (HR 1.02; 95% CI 0.77-1.35) or death (HR 1.10; 95% CI 0.84-1.45). However, sleeve gastrectomy (vs. no bariatric surgery) was associated with lower risk of graft failure (HR 0.39; 95% CI 0.16-0.95). In conclusion, history of bariatric surgery prior to kidney transplantation was not associated with allograft or patient survival, but findings varied by surgery type. Sleeve gastrectomy was associated with better graft survival and should be considered in severely obese transplant candidates receiving dialysis.

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.

Trends in Bariatric Surgery Procedures among Patients with ESKD in the United States

BACKGROUND AND OBJECTIVES

Despite the potential for improving health status or increasing access to transplantation, national practice patterns for bariatric surgery in obese patients with ESKD are poorly understood. The purpose of this study was to describe current trends in surgical care for this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using 100% Medicare data, we identified all beneficiaries undergoing bariatric surgery in the United States between 2006 and 2016. We evaluated longitudinal practice patterns using linear regression models. We also estimated risk-adjusted complications, readmissions, and length of stay using Poisson regression for patients with and without ESKD.

RESULTS

The number of patients with ESKD undergoing bariatric surgery increased ninefold between 2006 and 2016. The proportional use of sleeve gastrectomy increased from <1% in 2006 to 84% in 2016. For sleeve gastrectomy, complication rates were similar between patients with and without ESKD (3.4% versus 3.6%, respectively; difference, -0.3%; 95% confidence interval, -1.3% to 0.1%; P=0.57). However, patients with ESKD had more readmissions (8.6% versus 5.4%, respectively; difference, 3.2%; 95% confidence interval, 1.9% to 4.6%; P<0.001) and slightly longer hospitals stays (2.2 versus 1.9 days, respectively; difference, 0.3; 95% confidence interval, 0.1 to 0.4; P<0.001).

CONCLUSIONS

This study suggests that laparoscopic sleeve gastrectomy has replaced Roux-en-Y gastric bypass as the most common bariatric surgical procedure in patients with ESKD. The data also demonstrate a favorable complication profile in patients with sleeve gastrectomy.

Bariatric Surgery in Renal Transplant Patients

OBJECTIVES

The idea of transplanting organs is not new, nor is the disease of obesity. Obese transplant recipients have greater risk of early death than their cohorts, which is not due to increased rejection but due to obesity-related complications, including arterial hypertension, diabetes, and delayed graft function. Here, our aim was to evaluate the effects of bariatric surgery versus lifestyle changes on outcomes of moderate to severely obese renal transplant recipients.

MATERIALS AND METHODS

Twenty-two morbidly obese patients with stable graft function who underwent bariatric surgery were compared with 44 obese patients on lifestyle management (control group). Both groups were evaluated regarding graft and patient outcomes.

RESULTS

The studied groups were comparable demographically. In the bariatric study group versus control group, we observed that the mean body mass index was 38.49 ± 9.1 versus 44.24 ± 6 (P = .024) at transplant and 34.34 ± 7.6 versus 44.38 ± 6.7 (P = .002) at 6 months of bariatric surgery. Both groups received a more potent induction immunosuppression, but this was significantly higher in the obese nonbariatric control group (P < .05). There were more patients with slow and delayed graft functions in the same nonbariatric group. The 2 groups were comparable regarding new-onset diabetes after transplant, total patients with diabetes, and graft outcomes (P > .05).

CONCLUSIONS

Bariatric surgeries are feasible, safe pro cedures for selected obese renal transplant recipients.

From chronic kidney disease to kidney transplantation: The impact of obesity and its treatment modalities

Obesity is associated with worse short-term outcomes after kidney transplantation but the effect on long-term outcomes is unknown. Although some studies have reported worse outcomes for obese recipients when compared to recipients with a BMI in the normal range, obese recipients who receive a transplant have better outcomes than those who remain wait-listed. Whether transplant candidates should be advised to lose weight before or after transplant has been debated and this is mainly due to the gap in the literature linking pre-transplant weight loss with better outcomes post-transplantation. The issue is further complicated by the use of BMI as a metric of body fat, the obesity paradox in dialysis patients and the different ethical viewpoints of utility versus equity. Measures used to reduce weight loss, including orlistat and bariatric surgery (in particular those with a malabsorptive component), have been associated with enteric hyperoxaluria with consequent risk of nephrolithiasis and oxalate nephropathy. In this review, we discuss the evidence regarding the use of weight loss measures in the kidney transplant candidate and recipient with a view to recommending whether weight loss should be pursued before or after kidney transplantation.

The impact and treatment of obesity in kidney transplant candidates and recipients

The prevalence of obesity in patients with chronic kidney failure and renal transplant candidates has paralleled the epidemic in the general population. The associated risks of surgical complications and long-term cardiovascular death are significant: most transplant centers consider obesity a relative contra-indication for transplant.

Few studies have focused on conservative weight loss strategies in transplant patients. Studies using administrative databases have found that only a minority of wait-listed patients lose weight and with no apparent benefit to transplant outcomes. The only clinical trial in this area found that an intensive weight-loss program had significantly better success (to listing) than self-directed weight loss. However, only a minority that succeeded with the help of a program (36 %), while the “diet and exercise” group had negligible results.

Laparoscopy has radically shortened the recovery time and decreased the complications associated with bariatric surgery. Reports in transplant patients, who were previously deemed too medically complex, have demonstrated a dramatic and rapid weight loss. The only randomized clinical trial in patients with CKD, which compared sleeve gastrectomy to best medical care clearly favoured the surgical arm for weight loss, but was too small to assess other outcomes. The emerging experience is small but quite promising.

Surgical complications and the effect on immunosuppression remain the chief concerns regarding the use of bariatric surgery in transplant patients. Rigorous prospective studies will be essential to properly evaluate the expected weight loss and the effect on pharmacokinetics of immunosuppressive medications. A routine role for bariatric surgery in transplantation would require evidence of improvements in patient-important outcomes and evidence of safety.

Chronic dialysis discontinuation: a systematic narrative review of the literature in the new millennium

INTRODUCTION AND AIMS

Renal function recovery (RFR), defined as the discontinuation of dialysis after 3 months of replacement therapy, is an uncommon occurrence. At a time when the "too early" start of dialysis is in discussion, a systematic review of the literature for cases in which patients recovered renal function after starting dialysis with chronic indications, including single cases and large series, may lead to attention being focused on this interesting issue.

METHODS

The search strategy was built in Medline on Pubmed, in EMBASE and in the Cochrane Collaboration (August 2013) combining Mesh, Emtree and free terms: dialysis or hemodialysis, kidney function, renal function and recovery (publication date 2000-2013). The following tasks were performed in duplicate: titles and abstracts were manually screened, the data were extracted: title, author, objective, year, journal, period of study, multi-center, country, type of study.

RESULTS

The systematic review retrieved 1,894 titles; 58 full papers were retrieved and the final selection included 24 papers: 11 case series or Registry data (4 from ANZdata) and 13 case reports. In spite of the high heterogeneity of the studies, overall they suggest that RFR occurs in about 1% of patients, without differences between PD and HD. RFR appears to be more frequent in elderly patients with renal vascular disease (up to 10% RFR in cholesterol emboli or scleroderma), but is reported in all types of primary and secondary kidney diseases.

CONCLUSIONS

RFR is a clinical event that should be looked for, particularly in elderly patients with vascular comorbidity.

Obesity in CKD--what should nephrologists know?

Obesity, the epidemic of the 21st century, carries a markedly increased risk for comorbid complications, such as type 2 diabetes, cancer, hypertension, dyslipidemia, cardiovascular disease, and sleep apnea. In addition, obesity increases the risk for CKD and its progression to ESRD. Paradoxically, even morbid obesity associates with better outcomes in studies of ESRD patients on maintenance dialysis. Because the number of obese CKD and maintenance dialysis patients is projected to increase markedly in developed as well as low- and middle-income countries, obesity is a rapidly emerging problem for the international renal community. Targeting the obesity epidemic represents an unprecedented opportunity for health officials to ameliorate the current worldwide increase in CKD prevalence. Nephrologists need more information about assessing and managing obesity in the setting of CKD. Specifically, more precise estimation of regional fat distribution and the amount of muscle mass should be introduced into regular clinical practice to complement more commonly used practical markers, such as body mass index. Studies examining the effects of obesity on kidney disease progression and other clinical outcomes along with weight management strategies are much needed in this orphan area of research.

Roux-en-Y gastric bypass compared with aggressive diet and exercise therapy for morbidly obese patients awaiting renal transplant: a decision analysis

BACKGROUND

The optimal management of morbidly obese patients awaiting renal transplant is controversial and unknown. The objective of this study was to compare the impact of Roux-en-Y gastric bypass (RYGB) versus diet and exercise on the survival of morbidly obese patients with end-stage renal disease awaiting renal transplant.

METHODS

A decision analytic Markov state transition model was designed to simulate the life of morbidly obese patients with end-stage renal disease awaiting transplant. Life expectancy after RYGB and after 1 and 2 years of diet and exercise was estimated and compared in the framework of 2 clinical scenarios in which patients above a body mass index (BMI) of 35 kg/m(2) or above a BMI of 40 kg/m(2) were ineligible for transplantation, reflecting the BMI restrictions of many transplant centers. In addition to base case analysis (45 kg/m(2) BMI preintervention), sensitivity analysis of initial BMI was completed. Markov model parameters were extracted from the literature.

RESULTS

RYGB improved survival compared with diet and exercise. Patients who underwent RYGB received transplants sooner and in higher frequency. Using 40 kg/m(2) as the upper limit for transplant eligibility, base case patients who underwent RYGB gained 5.4 years of life, whereas patients who underwent 1 and 2 years of diet and exercise gained 1.5 and 2.8 years of life, respectively. Using 35 kg/m(2) as the upper limit, RYGB base case patients gained 5.3 years of life, whereas patients who underwent 1 and 2 years of diet and exercise gained .7 and 1.5 years of life, respectively.

CONCLUSIONS

In morbidly obese patients with end-stage renal disease, RYGB may be more effective than optimistic weight loss outcomes after diet and exercise, thereby improving access to renal transplantation.

Home hemodialysis: a successful option for obese and bariatric people with end-stage kidney disease

The increasing prevalence of obesity in developed countries is reflected in the chronic kidney disease, dialysis, and transplant populations. The added risk factor of obesity increases the risk of vascular events, inflammation, insulin resistance, blood pressure, dyslipidemia, and mortality risk. Nephrology center policies may exclude obese people from transplantation programs resulting in many years of dialysis. The case of a 215-kg Australian male who has successfully dialyzed at home for more than 8 years will be used to illustrate the important considerations and clinical support that these people require for successful home dialysis treatment. The aim of this paper is to report on a program that has successfully trained 23 obese (body mass index >30) people who commenced on home hemodialysis between 2001 and 2009. Body weight ranged between 94.0 and 215 kg (mean 126, SD 26.19) and body mass index ranged between 34.9 and 71 (mean 43.38, SD 9.99) at the start of home training. During the 8.5 years of follow-up, average time on home dialysis was 43.7 months. Home hemodialysis is a feasible treatment for obese people to facilitate longer and more frequent dialysis, resulting in improved hemodynamic stability and improved quality of life. For obese people with end-stage kidney disease, home hemodialysis has shown to be cost-effective and can result in greater treatment efficacy than in-center hospital dialysis.

Impact of bariatric surgery on comorbidities

Published data show that bariatric surgery not only leads to significant and sustained weight loss but also resolves or improves multiple comorbidities associated with morbid obesity. Evidence suggests that the earlier the intervention the better the resolution of comorbidities. Patients with metabolic syndrome and comorbidities associated with morbid obesity should be promptly referred for consideration for bariatric surgery earlier in the disease process.

Bariatric surgery and renal function

Obesity causes a significant healthcare burden and has been shown to be an important risk factor in the development of cardiovascular disease, type 2 diabetes, and increasingly chronic kidney disease. Bariatric surgery is the most effective treatment for obesity and has been shown to drastically improve both blood pressure and diabetic control. However, the interaction of bariatric surgery and renal function is less clear. This review focuses on the effect of bariatric surgery on renal function both in the acute situation, with respect to acute kidney injury, and also on changes in renal function parameters post-bariatric surgery weight loss. The interaction of obesity, bariatric surgery, and nephrolithiasis as a precipitant of acute kidney injury will also be considered. The role of bariatric surgery in pre- and post-renal transplant recipients is discussed as well as possible mechanisms underlying the improvement in renal function.