A "weight-listing" paradox for candidates of renal transplantation?

Collaborative Approach Toward Transplant Candidacy for Obese Patients with End-Stage Renal Disease

BACKGROUND

An elevated BMI is a major cause of transplant preclusion for patients with end-stage renal disease (ESRD). This phenomenon exacerbates existing socioeconomic and racial disparities and increases the economic burden of maintaining patients on dialysis. Metabolic bariatric surgery (MBS) in such patients is not widely available. Our center created a collaborative program to undergo weight loss surgery before obtaining a kidney transplant.

STUDY DESIGN

We studied the outcomes of these patients after MBS and transplant surgery. One hundred eighty-three patients with ESRD were referred to the bariatric team by the transplant team between January 2019 and June 2023. Of these, 36 patients underwent MBS (20 underwent Roux-en-Y gastric bypass and 16 underwent sleeve gastrectomy), and 10 underwent subsequent transplantation, with another 15 currently waitlisted. Both surgical teams shared resources, including dieticians, social workers, and a common database, for easy transition between teams.

RESULTS

The mean starting BMI for all referrals was 46.4 kg/m 2 and was 33.9 kg/m 2 at the time of transplant. The average number of hypertension medications decreased from 2 (range 2 to 4) presurgery to 1 (range 1 to 3) postsurgery. Similarly, hemoglobin A1C levels improved, with preoperative averages at 6.2 (range 5.4 to 7.6) and postoperative levels at 5.2 (range 4.6 to 5.8) All transplants are currently functioning, with a median creatinine of 1.5 (1.2 to 1.6) mg/dL (glomerular filtration rate 46 [36.3 to 71]).

CONCLUSIONS

A collaborative approach between bariatric and transplant surgery teams offers a pathway toward transplant for obese ESRD patients and potentially alleviates existing healthcare disparities. ESRD patients who undergo MBS have unique complications to be aware of. The improvement in comorbidities may lead to superior posttransplant outcomes.

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.

Obesity Weight Loss Phenotypes in CKD: Findings From the Chronic Renal Insufficiency Cohort Study

Introduction

Although people with chronic kidney disease (CKD) and obesity have important motivations to lose weight, weight loss is also associated with health risks. We examined whether patterns of change in systolic blood pressure (SBP), serum albumin level, and fat-free mass (FFM) can help to differentiate between healthy and high-risk weight loss in this population.

Methods

Using data from the Chronic Renal Insufficiency Cohort Study (CRIC), we estimated a joint multivariate latent class model with 6 classes to identify distinct trajectories of body mass index (BMI), albumin, and SBP among participants with obesity (BMI ≥30 kg/m2 at baseline), accounting for informative missingness from death. In a secondary analysis, we fit a 6-class model with BMI and FFM.

Results

Among 2831 participants (median baseline BMI 35.6, interquartile range [IQR] 32.4-40.0 kg/m2), median follow-up was 6.8 (IQR 4.8-12.9) years, median age was 61 (IQR 54-67) years, 53% were male, 50% were non-Hispanic Black, and 82% were trying to control or lose weight at baseline. Latent classes were associated with mortality risk (5-year cumulative incidence of mortality 6.8% and 1.5% in class 6 and 3, respectively). Class 6 had the highest mortality rate and was characterized by early, steep BMI loss, early serum albumin decline, and late SBP increase. In the secondary analysis, a class characterized by steep BMI and FFM loss was associated with the highest death risk.

Conclusions

Among adults with CKD and obesity, BMI loss with concomitant serum albumin or FFM loss was associated with a high risk of death.

Obesity is Associated With Delayed Graft Function in Kidney Transplant Recipients: A Paired Kidney Analysis

Obesity is increasingly prevalent among candidates for kidney transplantation. Existing studies have shown conflicting post-transplant outcomes for obese patients which may relate to confounding bias from donor-related characteristics that were unaccounted for. We used ANZDATA Registry data to compare graft and patient survival between obese (BMI >27.5 kg/m2 Asians; >30 kg/m2 non-Asians) and non-obese kidney transplant recipients, while controlling for donor characteristics by comparing recipients of paired kidneys. We selected transplant pairs (2000-2020) where a deceased donor supplied one kidney to an obese candidate and the other to a non-obese candidate. We compared the incidence of delayed graft function (DGF), graft failure and death by multivariable models. We identified 1,522 pairs. Obesity was associated with an increased risk of DGF (aRR = 1.26, 95% CI 1.11-1.44, p < 0.001). Obese recipients were more likely to experience death-censored graft failure (aHR = 1.25, 95% CI 1.05-1.49, p = 0.012), and more likely to die with function (aHR = 1.32, 95% CI 1.15-1.56, p = 0.001), versus non-obese recipients. Long-term patient survival was significantly worse in obese patients with 10- and 15-year survival of 71% and 56% compared to 77% and 63% in non-obese patients. Addressing obesity is an unmet clinical need in kidney transplantation.

Post-kidney transplant body mass index trajectories are associated with graft loss and mortality

BACKGROUND

Early post-kidney transplantation (KT) changes in physiology, medications, and health stressors likely impact body mass index (BMI) and likely impact all-cause graft loss and mortality.

METHODS

We estimated 5-year post-KT (n = 151 170; SRTR) BMI trajectories using an adjusted mixed effects model. We estimated long-term mortality and graft loss risks by 1-year BMI change quartile (decrease [1st quartile]: change < -.07 kg/m2 /month; stable [2nd quartile]: -.07 ≤ change ≤ .09 kg/m2 /month; increase [3rd, 4th quartile]: change > .09 kg/m2 /month) using adjusted Cox proportional hazards models.

RESULTS

BMI increased in the 3 years post-KT (.64 kg/m2 /year, 95% CI: .63, .64) and decreased in years 3-5 (-.24 kg/m2 /year, 95% CI: -.26, -.22). 1-year post-KT BMI decrease was associated with elevated risks of all-cause mortality (aHR = 1.13, 95% CI: 1.10-1.16), all-cause graft loss (aHR = 1.13, 95% CI: 1.10-1.15), death-censored graft loss (aHR = 1.15, 95% CI: 1.11-1.19), and mortality with functioning graft (aHR = 1.11, 95% CI: 1.08-1.14). Among recipients with obesity (pre-KT BMI≥30 kg/m2 ), BMI increase was associated with higher all-cause mortality (aHR = 1.09, 95% CI: 1.05-1.14), all-cause graft loss (aHR = 1.05, 95% CI: 1.01-1.09), and mortality with functioning graft (aHR = 1.10, 95% CI: 1.05-1.15) risks, but not death-censored graft loss risks, relative to stable weight. Among individuals without obesity, BMI increase was associated with lower all-cause graft loss (aHR = .97, 95% CI: .95-.99) and death-censored graft loss (aHR = .93, 95% CI: .90-.96) risks, but not all-cause mortality or mortality with functioning graft risks.

CONCLUSIONS

BMI increases in the 3 years post-KT, then decreases in years 3-5. BMI loss in all adult KT recipients and BMI gain in those with obesity should be carefully monitored post-KT.

Retrospective analysis of the impact of severe obesity on kidney transplant outcomes

BACKGROUND

The prevalence of obesity among kidney transplant recipients is rising. We sought to determine the association between recipient body mass index (BMI) and post-transplant complications.

METHODS

Single-center, retrospective cohort study of all adult kidney transplant recipients from 2004 to 2020. Recipients were stratified into four BMI categories: normal-weight (BMI 18.5-24.9 kg/m2, n = 1020), overweight (BMI 25-29.9 kg/m2, n = 1002), moderately obese (BMI 30-34.9 kg/m2, n = 510) and severely-to-morbidly obese (BMI ≥35 kg/m2, n = 274). Logistic regression was used to estimate the association between BMI category and surgical site infections (SSIs).

RESULTS

Recipients with BMI ≥35 kg/m2 had significantly higher rates of SSIs (P < .0001) compared with recipients in all other categories. On multivariable analysis, recipients with BMI ≥35 kg/m2 had increased odds of SSIs compared with normal-weight recipients [odds ratio (OR) 3.34, 95% confidence interval (CI) 1.55-7.22, P = .022). On multivariable and Kaplan-Meier analyses, no BMI groups demonstrated increased odds for death-censored graft failure.

CONCLUSION

Severe obesity in kidney transplant recipients is associated with increased SSIs, but not kidney allograft failure.

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.

Obesity Management in Kidney Transplant Candidates: Current Paradigms and Gaps in Knowledge

In this review, we discuss the increasing prevalence of obesity among people with chronic and end-stage kidney disease (ESKD) and implications for kidney transplant (KT) candidate selection and management. Although people with obesity and ESKD receive survival and quality-of-life benefits from KT, most KT programs maintain strict body mass index (BMI) cutoffs to determine transplant eligibility. However, BMI does not distinguish between visceral adiposity, which confers higher cardiovascular risks and risks of perioperative and adverse posttransplant outcomes, and muscle mass, which is protective in ESKD. Furthermore, requirements for patients with obesity to lose weight before KT should be balanced with the findings of numerous studies that show weight loss is a risk factor for death among patients with ESKD, independent of starting BMI. Data suggest that KT is associated with survival benefits relative to remaining on dialysis for candidates with obesity although recipients without obesity have higher delayed graft function rates and longer transplant hospitalization durations. Research is needed to determine the optimal body composition metrics for KT candidacy assessments and risk stratification. In addition, ESKD-specific obesity management guidelines are needed that will address the neurologic, behavioral, socioeconomic, and physical underpinnings of this increasingly common disease.

Impact of obesity in kidney transplantation: a prospective cohort study from French registries between 2008 and 2014

BACKGROUND

The access of obese patients to kidney transplantation is limited despite several studies showing that obese transplant recipients had a better survival rate than those undergoing dialysis. The aim of this study was to compare patient and graft survival rates and post-renal transplant complications in obese patients and non-obese patients and to assess the effect of pre-transplant weight loss in obese patients on transplant outcomes.

METHODS

We carried out a prospective cohort study using two French registries REIN and CRISTAL on 7 270 kidney transplant patients between 2008 and 2014 in France. We compared obese patients with non-obese patients and obese patients who lost more than 10% of weight before the transplant (Obese WL and Obese nWL).

RESULTS

The mean BMI in our obese patients was 32 kg/m2. Graft survival was lower in obese patients than in non-obese patients (HR = 1.40, IC 95% [1.09; 1.78], P = 0.007) whereas patient survival was similar (HR = 0.94, IC 95% [0.73; 1.23], P = 0.66). Graft survival was significantly lower in Obese WL than in Obese nWL (HR = 2.17, CI 95% [1.02; 4.63], P = 0.045) whereas patient survival was similar in the two groups (HR = 0.79, IC 95% [0.35; 1.77], P = 0.56).

CONCLUSION

Grade I obesity does not seem to be a risk factor for excess mortality after kidney transplantation and should not be an obstacle to having access to a graft. Weight loss before a kidney transplant in this patients should not be essential for registration on waiting list.

Bariatric surgery in transplant recipients: A narrative review

Morbidity and mortality rates are increased due to obesity after organ transplantation; in this regards, bariatric surgery (BS) is believed to be an effective treatment for posttransplant obese patients. Nevertheless, some studies are doubtful in terms of the effectiveness of BS, the most suitable bariatric procedure, and management of immunosuppressant drugs in some kinds of organ transplants. We evaluated nonsurgical therapies, weight reduction, adjustment of immunosuppressants, comorbidities, and the recommended surgical procedures for posttransplant BS for different types of organ transplantations.

Obesity and Post-Transplant Diabetes Mellitus in Kidney Transplantation

Worldwide, the prevalence obesity, diabetes, and chronic kidney disease is increasing apace. The relationship between obesity and chronic kidney disease is multidimensional, especially when diabetes is also considered. The optimal treatment of patients with chronic kidney disease includes the need to consider weight loss as part of the treatment. The exact relationship between obesity and kidney function before and after transplantation is not as clear as previously imagined. Historically, patients with obesity had worse outcomes following kidney transplantation and weight loss before surgery was encouraged. However, recent studies have found less of a correlation between obesity and transplant outcomes. Transplantation itself is also a risk factor for developing diabetes, a condition known as post-transplant diabetes mellitus, and is related to the use of immunosuppressive medications and weight gain following transplantation. Newer classes of anti-diabetic medications, namely SGLT-2 inhibitors and GLP-1 agonists, are increasingly being recognized, not only for their ability to control diabetes, but also for their cardio and renoprotective effects. This article reviews the current state of knowledge on the management of obesity and post-transplant diabetes mellitus for kidney transplant patients.

Poor kidney graft survival in anorexia nervosa patients

BACKGROUND

Anorexia nervosa is a condition associated with poor outcomes in a variety of circumstances such as recurrence of eating disorders, psychiatric disorders, and organ damage.

OBJECTIVE

In the present study, we first sought to determine the 5-year kidney graft survival in patients with anorexia nervosa and then to evaluate the BMI course and medical complications.

METHODS

In this multicenter, retrospective, case-control study, we analyzed the impact of anorexia nervosa on graft outcomes compared to transplant recipients with low or normal BMI.

RESULTS

We enrolled 137 women in this study: 19 with anorexia nervosa, 59 with low BMI (BMI < 18.5 kg/m²), and 59 with normal BMI (18.5-24.9 kg/m²). Anorexia nervosa was significantly associated with lower graft survival compared to either of the other groups (hazard ratio 5.5 [95% CI 3.4-8.9], p = 0.005); there was no difference in graft survival between patients with low or normal BMI. Cardiovascular complications were more frequent in the anorexia nervosa group (37%) than in patients with low (6%) or normal BMI (7%) (p = 0.001).

CONCLUSION

We conclude that patients with anorexia nervosa should be considered a high-risk group.

LEVEL OF EVIDENCE

Level III, evidence obtained from well-designed cohort or case-control analytic studies.

Pre-Kidney Transplant Unintentional Weight Loss Leads to Worse Post-Kidney Transplant Outcomes

BACKGROUND

Weight loss before kidney transplant (KT) is a known risk factor for weight gain and mortality; however, whereas unintentional weight loss is a marker of vulnerability, intentional weight loss might improve health. We tested whether pre-KT unintentional and intentional weight loss have differing associations with post-KT weight gain, graft loss, and mortality.

METHODS

Among 919 KT recipients from a prospective cohort study, we used adjusted mixed effects models to estimate post-KT BMI trajectories, and Cox models to estimate death-uncensored graft loss, death-censored graft loss, and all-cause mortality by one-year pre-KT weight change category [stable weight (change≤5%), intentional weight loss (loss>5%), unintentional weight loss (loss>5%), and weight gain (gain>5%)].

RESULTS

Mean age was 53 years, 38% were Black, and 40% were female. In the pre-KT year, 62% of recipients had stable weight, 15% had weight gain, 14% had unintentional weight loss, and 10% had intentional weight loss. In the first three years post-KT, BMI increases were similar among those with pre-KT weight gain and intentional weight loss, and lower compared to those with unintentional weight loss (difference +0.79 kg/m2/year, 95% CI: 0.50-1.08 kg/m2/year, p < 0.001). Only unintentional weight loss was independently associated with higher death-uncensored graft loss (adjusted Hazard Ratio [aHR]=1.80, 95% CI:1.23-2.62), death-censored graft loss (aHR=1.91, 95% CI:1.12-3.26) and mortality (aHR=1.72, 95% CI:1.06-2.79) relative to stable pre-KT weight.

CONCLUSIONS

This study suggests that unintentional, but not intentional, pre-KT weight loss is an independent risk factor for adverse post-KT outcomes.

KDIGO Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation

The 2020 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation is intended to assist health care professionals worldwide who evaluate and manage potential candidates for deceased or living donor kidney transplantation. This guideline addresses general candidacy issues such as access to transplantation, patient demographic and health status factors, and immunological and psychosocial assessment. The roles of various risk factors and comorbid conditions governing an individual's suitability for transplantation such as adherence, tobacco use, diabetes, obesity, perioperative issues, causes of kidney failure, infections, malignancy, pulmonary disease, cardiac and peripheral arterial disease, neurologic disease, gastrointestinal and liver disease, hematologic disease, and bone and mineral disorder are also addressed. This guideline provides recommendations for evaluation of individual aspects of a candidate's profile such that each risk factor and comorbidity are considered separately. The goal is to assist the clinical team to assimilate all data relevant to an individual, consider this within their local health context, and make an overall judgment on candidacy for transplantation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Guideline recommendations are primarily based on systematic reviews of relevant studies and our assessment of the quality of that evidence, and the strengths of recommendations are provided. Limitations of the evidence are discussed with differences from previous guidelines noted and suggestions for future research are also provided.

Effects of body mass index on kidney transplant outcomes are significantly modified by patient characteristics

Body mass index (BMI) is a known risk factor associated with kidney transplant outcomes and is incorporated for determining transplant candidate eligibility. However, BMI is a coarse health measure and risks associated with BMI may vary by patient characteristics. We evaluated 296 807 adult (age > 17) solitary kidney transplant recipients from the Scientific Registry of Transplant Recipients (2000-2019). We examined effects of BMI using survival models and tested interactions with recipient characteristics. Overall, BMI demonstrated a "J-Shaped" risk profile with elevated risks for overall graft loss with low BMI and obesity. However, multivariable models indicated interactions between BMI with recipient age, diagnosis, gender, and race/ethnicity. Low BMI was relatively higher risk for older recipients (>60 years), people with type I diabetes, and males and demonstrated no additional risk among younger (18-39) and Hispanic recipients. High BMI was associated with elevated risk for Caucasians and attenuated risk among African Americans and people with type II diabetes. Effects of BMI had variable risks for mortality vs graft loss by recipient characteristics in competing risks models. The association of BMI with posttransplant outcomes is highly variable among kidney transplant recipients. Results are important considerations for personalized care and risk stratification. Findings suggest that transplant contraindications should not be based on absolute BMI thresholds but modified based on patient characteristics.

Weighing the waitlist: Weight changes and access to kidney transplantation among obese candidates

High body mass index is a known barrier to access to kidney transplantation in patients with end-stage kidney disease. The extent to which weight and weight changes affect access to transplantation among obese candidates differentially by race/ethnicity has received little attention. We included 10 221 obese patients waitlisted for kidney transplantation prior to end-stage kidney disease onset between 1995–2015. We used multinomial logistic regression models to examine the association between race/ethnicity and annualized change in body mass index (defined as stable [-2 to 2 kg/m²/year], loss [>2 kg/m²/year] or gain [>2 kg/m²/year]). We then used Fine-Gray models to examine the association between weight changes and access to living or deceased donor transplantation by race/ethnicity, accounting for the competing risk of death. Overall, 29% of the cohort lost weight and 7% gained weight; 46% received a transplant. Non-Hispanic blacks had a 24% (95% CI 1.12–1.38) higher odds of weight loss and 22% lower odds of weight gain (95% CI 0.64–0.95) compared with non-Hispanic whites. Hispanics did not differ from whites in their odds of weight loss or weight gain. Overall, weight gain was associated with lower access to transplantation (HR 0.88 [95% CI 0.79–0.99]) compared with maintenance of stable weight, but weight loss was not associated with better access to transplantation (HR 0.96 [95% CI 0.90–1.02]), although this relation differed by baseline body mass index and for recipients of living versus deceased donor organs. For example, weight loss was associated with improved access to living donor transplantation (HR 1.24 [95% CI 1.07–1.44]) in whites but not in blacks or Hispanics. In a cohort of obese patients waitlisted before dialysis, blacks were more likely to lose weight and less likely to gain weight compared with whites. Weight loss was only associated with improved access to living donor transplantation among whites. Further studies are needed to understand the reasons for the observed associations.

Body mass index, weight-adjusted immunosuppression and the risk of acute rejection and infection after kidney transplantation: a cohort study

BACKGROUND

Body mass index (BMI) is associated with patient outcomes after kidney transplantation. We hypothesized that immunosuppression (IS) dosing is a contributing factor.

METHODS

Using Australia and New Zealand Dialysis and Transplant registry data, we included all adult kidney-only transplant recipients over 2000-14 treated with prednisolone, mycophenolate and tacrolimus/cyclosporin (n = 7919). The exposure was BMI and the outcomes were time to: (i) acute rejection, (ii) fatal infection, (iii) cancer and (iv) graft; and (v) patient survival. We modelled BMI and IS dosing (in quartiles) as time-varying covariates in extended Cox models.

RESULTS

Compared with a BMI of 25 kg/m2, a BMI of 35 was associated with acute rejection after adjusting for demographics and comorbidities [adjusted hazard ratio (aHR) = 1.29, 95% confidence interval (CI) 1.12-1.49]. This association virtually disappeared after correcting for IS (aHR = 1.09, 95% CI 0.93-1.29). A BMI of 35 was non-significantly associated with fewer fatal infections (aHR = 0.91, 95% CI 0.66-1.25), but this reversed after adjusting for IS (aHR = 1.54, 95% CI 1.03-2.28). Results for cancer were not significantly altered after adjusting for IS. Results for lower BMI were similarly not significantly altered though generally associated with worse outcomes.

CONCLUSIONS

Our findings show that the associations between high BMI, acute rejection and fatal infection after kidney transplantation were significantly altered after correcting for IS suggesting that relative under-dosing of obese patients may partially explain these associations.

Efficacy and Safety of Intra-gastric Balloon Placement in Dialyzed Patients Awaiting Kidney Transplantation

BACKGROUND

The number of obese patients who are candidates for renal transplantation has considerably increased, but obesity can be a barrier to kidney transplantation. Weight loss is often difficult through diet alone. We studied the efficacy and tolerance of the intra-gastric balloon (IGB) procedure in obese patients who were undergoing dialysis and were candidates for a renal transplantation.

PATIENTS AND METHODS

Obese patients (BMI > 30 kg/m²) who were candidates for renal transplantation were prospectively included in the study between 2010 and 2012. The balloon was inserted and removed during a gastric endoscopy under general anesthesia. The treatment lasted 6 months. The end point was a decrease in BMI after 6 months. Body impedance spectrometry (BIS) and nutritional statute were evaluated initially and then after IGB removal.

RESULTS

Seventeen patients (nine females and eight males) with a mean age of 53.4 years [19.4-69.4] were included. The decrease in body mass index (BMI) during the 6-month placement was 3 kg/m² (from 37.7 to 34.4 kg/m²). The mean weight loss was 7 kg. The mean percentage of excess weight loss after 6 months was 20.2 (± 11.4). The tolerance was good without any complications. Eleven patients underwent kidney transplantation.

CONCLUSION

IGB in obese dialyzed patients who are candidates for renal transplantation is safe and effective. However, the amount of weight loss can vary.

Association Between Weight Loss Before Deceased Donor Kidney Transplantation and Posttransplantation Outcomes

RATIONALE & OBJECTIVE

There is debate on whether weight loss, a hallmark of frailty, signals higher risk for adverse outcomes among recipients of deceased donor kidney transplantation (DDKT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using national Organ Procurement and Transplantation Network data, we included all DDKT recipients in the United States between December 4, 2004, and December 3, 2014, who were adults (aged ≥ 18 years) when listed for DDKT.

EXPOSURES

Relative pre-DDKT weight change as a continuous predictor and categorized as <5% weight change from listing to DDKT, ≥5% to <10% weight loss, ≥10% weight loss, ≥5% to <10% weight gain, and ≥10% weight gain.

OUTCOMES

We examined 3 post-DDKT outcomes: (1) transplant hospitalization length of stay (LOS) in days, (2) all-cause graft failure, and (3) mortality.

ANALYTIC APPROACH

Unadjusted fractional polynomial methods, multivariable log-gamma models, and multivariable Cox proportional hazards models.

RESULTS

Among 94,465 recipients of DDKT, median pre-DDKT weight change was 0 (interquartile range, -3.5 to +3.9) kg. There were nonlinear unadjusted associations between relative pre-DDKT weight loss and longer transplant hospitalization LOS, higher all-cause graft loss, and higher mortality. Compared with recipients with <5% pre-DDKT weight change (n = 49,366; 52%), recipients who lost ≥10% of their listing weight (n = 10,614; 11%) had 0.66 (95% CI, 0.23-1.09) days longer average transplant hospitalization LOS (P = 0.003), 1.11-fold higher graft loss (adjusted HR [aHR], 1.11; 95% CI, 1.06-1.17; P < 0.001), and 1.18-fold higher mortality (aHR, 1.18; 95% CI, 1.11-1.25; P < 0.001) independent of recipient, donor, and transplant factors. Pre-DDKT dialysis exposure, listing body mass index category, and waiting time modified the association of pre-DDKT weight change with hospital LOS (interaction P < 0.10), but not with all-cause graft loss and mortality.

LIMITATIONS

Unmeasured confounders and inability to identify volitional weight change. Also, the higher significance level set to increase the power of detecting interactions with the fixed sample size may have resulted in increased risk for type 1 error.

CONCLUSIONS

DDKT recipients with ≥10% pre-DDKT weight loss are at increased risk for adverse outcomes and may benefit from augmented support post-DDKT.

Obesity in Kidney Transplantation: Impact on Transplant Candidates, Recipients, and Donors

Obesity is now common among children and adults who are kidney transplant candidates and recipients. It is associated with an increased risk of cardiovascular disease and kidney failure. This also pertains to potential living kidney donors with obesity. Obese patients with end-stage renal disease benefit from transplantation as do nonobese patients, but obesity is also associated with more risk. A complicating factor is that obesity is also associated with increased survival on maintenance dialysis in adults, but not in children. The assessment of obesity and body habitus should be individualized. Body mass index is a common but imperfect indicator of obesity. The medical management of obesity in renal failure patients is often unsuccessful. Bariatric surgery, specifically laparoscopic sleeve gastrectomy, can result in significant weight loss with reduced morbidity, but many patients do not agree to undergo this treatment. The best approach to manage obese transplant candidates and recipients is yet unresolved.

Weight management strategies for those with chronic kidney disease: A consensus report from the Asia Pacific Society of Nephrology and Australia and New Zealand Society of Nephrology 2016 renal dietitians meeting

AIM

The aim of the present study was to develop a consensus report to guide dietetic management of overweight or obese individuals with chronic kidney disease (CKD).

METHODS

Six statements relating to weight management in CKD guided a comprehensive review of the literature. A summary of the evidence was then presented at the renal nutrition meeting of the 2016 Asia Pacific Society of Nephrology and Australia and New Zealand Society of Nephrology. Majority agreement was defined as group agreement on a statement of between 50-74%, and consensus was considered ≥75% agreement. The recommendations were developed via a mini Delphi process.

RESULTS

Two statements achieved group consensus: the current guidelines used by dietitians to estimate energy requirements for overweight and obese people with CKD are not relevant and weight loss medications may be unsafe or ineffective in isolation for those with CKD. One statement achieved group agreement: Meal replacement formulas are safe and efficacious in those with CKD. No agreement was achieved on the statements of whether there is strong evidence of benefit for weight loss prior to kidney transplantation; whether traditional weight loss strategies can be used in those with CKD and if bariatric surgery in those with end stage kidney disease is feasible and effective.

CONCLUSION

There is a limited evidence base to guide the dietetic management of overweight and obese individuals with CKD. Medical or surgical strategies to facilitate weight loss are not recommended in isolation and require a multidisciplinary approach with the involvement of a skilled renal dietitian.

Renal Transplant in Obese Patients and Impact of Weight Loss Before Surgery on Surgical and Medical Outcomes: A Single-Center Cohort Study

OBJECTIVES

Previous studies have linked obesity to poor outcomes in renal transplant recipients, prompting many transplant centers to encourage weight loss pretransplant in obese patients. Here, we performed a single-center retrospective study to assess the effects of weight loss on graft and patient outcomes.

MATERIALS AND METHODS

Data from 893 renal transplant recipients at our center from 2007 to 2011 were analyzed. First, renal transplant recipients with a history of obesity before transplant (42%) were compared with nonobese patients. Second, in the obese group, renal transplant recipients with significant weight loss (> 10%) before transplant were compared with other obese renal transplant recipients without significant weight loss.

RESULTS

Renal transplant recipients were predominantly white, with 74% having undergone living-donor transplant. Obese patients were older (56.6 vs 46.7 y old) and had more comorbidities and more surgical complications, in particular wound complications and incisional hernias, posttransplant than nonobese patients (14.7 vs 5.5%, respectively). Patient and graft survival rates were similar to those in nonobese patients. In the obese group, patient characteristics and medical or surgical complications after transplant did not differ between those with or without significant weight loss. However, obese patient and graft survival rates were lower in patients with weight loss than in obese patients without weight loss.

CONCLUSIONS

In our study, weight loss before transplant surgery in obese patients had no influence on surgical outcomes but was associated with a higher mortality rate. A prospective assessment of the impact of weight loss before surgery is needed to establish its usefulness.

Nutritional Management for Chronic Kidney Disease Patients who Undergo Bariatric Surgery: A Narrative Review

Bariatric surgery (BS) may be effective for chronic kidney disease (CKD) patients by reducing microalbuminuria and proteinuria, and by facilitating their meeting inclusion criteria for kidney transplantation. However, nutritional management for this population is complex and specific guidelines are scarce. A literature search was performed to create dietetic practice for these patients based on the most recent evidence. For the purposes of nutritional recommendations, we divided the patients into 2 subgroups: 1) patients with CKD and dialysis, and 2) patients after kidney transplantation. Before surgery, nutritional care includes nutritional status evaluation and adjusting doses of supplements to treat deficiencies and daily nutrient intake according to the dietary restrictions derived from kidney disease, including quantities of fluids, protein, phosphorus, potassium, and vitamins. After BS, these patients are at major risk for lean body mass loss, malnutrition and dehydration because of fluid restriction and diuretics. Postoperative nutritional recommendations should be carefully tailored according to CKD nutritional limitations and include specific considerations regarding protein, fluids, and supplementation, in particular calcium, vitamin A, and vitamin D. Nutritional management of CKD and kidney transplant patients undergoing BS is challenging and future studies are required to establish uniform high-level evidence-based guidelines.

[Impact of obesity in kidney transplantation: Monocentric cohort study and review of the literature]

Post-kidney transplantation outcomes in obese patients remain uncertain. The aim of this study is to compare patient and graft survival and post-transplant complications in obese patients and non-obese patients. We performed a retrospective analysis of a sample of 245kidney transplantations performed between 2008 and 2014 in Clermont-Ferrand. Obese patients and non-obese patients have been compared. Then we compared obese patients who have lost at least 5% of their weight (OPP) with obese patients who did not lose weight (OPS), and non-obese patients who have lost at least 5% of their weight (NOPP) with non-obese patients who did not lose weight (NOPS). Patient survival at 5years is similar between obese and non obese (84.06% versus 90.96%; P=0.49), between OPP and OPS (88.89% versus 81.82%; P=0.34) and between NOPP and NOPS (89.19% versus 91.05%; P=0.73). At 5years, graft survival is also comparable between obese and non obese (88.82% versus 81.86%; P=0.58), between OPP and OPS (85.56% versus 91.06%; P=0.98) and between NOPP and NOPS (88% versus 80.12%; P=0.31). The length of hospitalization and the rate of complications seem similar between obese and non obese and between OPP and OPS. Post-transplantation outcomes are similar between obese and non-obese patients and a weight loss for obese patients does not seem to decrease the risk of post-transplant complication.

Impact of screening for metabolic syndrome on the evaluation of obese living kidney donors

BACKGROUND

We report our experience with metabolic syndrome screening for obese living kidney donor candidates to mitigate the long-term risk of CKD.

METHODS

We retrospectively reviewed 814 obese (BMI≥30) and 993 nonobese living kidney donor evaluations over 12 years. Using logistic regression, we explored interactions between social/clinical variables and candidate acceptance before and after policy implementation.

RESULTS

Obese donor candidate acceptance decreased after metabolic syndrome screening began (56.3%, 46.3%, p < 0.01), while nonobese candidate acceptance remained similar (59.6%, 59.2%, p = 0.59). Adjusting for age, gender, race, BMI, and number of prior evaluations, acceptance of obese candidates decreased significantly more than nonobese (p = 0.025). In candidates without metabolic syndrome, there was no significant change in how age, sex, race, or BMI affected a donor candidate's probability of acceptance.

CONCLUSION

Metabolic syndrome screening is a simple stratification tool for centers with liberal absolute BMI cut-offs to exclude potentially higher-risk obese candidates.

The Diet and Haemodialysis Dyad: Three Eras, Four Open Questions and Four Paradoxes. A Narrative Review, Towards a Personalized, Patient-Centered Approach

The history of dialysis and diet can be viewed as a series of battles waged against potential threats to patients' lives. In the early years of dialysis, potassium was identified as "the killer", and the lists patients were given of forbidden foods included most plant-derived nourishment. As soon as dialysis became more efficient and survival increased, hyperphosphatemia, was identified as the enemy, generating an even longer list of banned aliments. Conversely, the "third era" finds us combating protein-energy wasting. This review discusses four questions and four paradoxes, regarding the diet-dialysis dyad: are the "magic numbers" of nutritional requirements (calories: 30-35 kcal/kg; proteins > 1.2 g/kg) still valid? Are the guidelines based on the metabolic needs of patients on "conventional" thrice-weekly bicarbonate dialysis applicable to different dialysis schedules, including daily dialysis or haemodiafiltration? The quantity of phosphate and potassium contained in processed and preserved foods may be significantly different from those in untreated foods: what are we eating? Is malnutrition one condition or a combination of conditions? The paradoxes: obesity is associated with higher survival in dialysis, losing weight is associated with mortality, but high BMI is a contraindication for kidney transplantation; it is difficult to limit phosphate intake when a patient is on a high-protein diet, such as the ones usually prescribed on dialysis; low serum albumin is associated with low dialysis efficiency and reduced survival, but on haemodiafiltration, high efficiency is coupled with albumin losses; banning plant derived food may limit consumption of "vascular healthy" food in a vulnerable population. Tailored approaches and agreed practices are needed so that we can identify attainable goals and pursue them in our fragile haemodialysis populations.

Evolution of body weight parameters up to 3 years after solid organ transplantation: The prospective Swiss Transplant Cohort Study

Obesity and weight gain are serious concerns after solid organ transplantation (Tx); however, no unbiased comparison regarding body weight parameter evolution across organ groups has yet been performed. Using data from the prospective nationwide Swiss Transplant Cohort Study, we compared the evolution of weight parameters up to 3 years post-Tx in 1359 adult kidney (58.3%), liver (21.7%), lung (11.6%), and heart (8.4%) recipients transplanted between May 2008 and May 2012. Changes in mean weight and body mass index (BMI) category were compared to reference values from 6 months post-Tx. At 3 years post-Tx, compared to other organ groups, liver Tx recipients showed the greatest weight gain (mean 4.8±10.4 kg), 57.4% gained >5% body weight, and they had the highest incidence of obesity (38.1%). After 3 years, based on their BMI categories at 6 months, normal weight and obese liver Tx patients, as well as underweight kidney, lung and heart Tx patients had the highest weight gains. Judged against international Tx patient data, the majority of our Swiss Tx recipients' experienced lower post-Tx weight gain. However, our findings show weight gain pattern differences, both within and across organ Tx groups that call for preventive measures.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

Medical Weight Loss Treatment Options in Obese Solid-Organ Transplant Candidates

With the increasing incidence of obesity in our country, the rate of obesity seen in organ transplant candidates is also rising. Accurate descriptions and measures of weight and degree of obesity vary between organ systems. Weight loss can be achieved in some patients while they wait for the transplant surgery. Weight reduction in transplant candidates involves a team approach, with a program of education and support, including medical nutrition therapy, physical therapy, and psychological support. The safety and applicability of weight loss medications to assist with pretransplant weight loss is also not well understood. It is not yet well known if weight loss before transplantation will improve posttransplant outcomes. Many questions regarding the treatment of obesity in transplant candidates remain unanswered.

Renal transplant among type 1 and type 2 diabetes patients in Spain: A population-based study from 2002 to 2013

BACKGROUND

To describe trends in the rates and short-term outcomes of renal transplants (RTx) among patients with or without diabetes in Spain (2002-2013).

METHODS

We used national hospital discharge data to select all hospital admissions for RTx. We divided the study period into four three-year periods. Rates were calculated stratified by diabetes status: type 1 diabetes (T1DM), type 2 diabetes (T2DM) and no-diabetes. We analyzed Charlson comorbidity index (CCI), post-transplant infections, in-hospital complications of RTx, rejection, in-hospital mortality and length of hospital stay.

FINDINGS

We identified 25,542 RTx. Rates of RTx increased significantly in T2DM patients over time (from 9.3 cases/100,000 in 2002/2004 to 13.3 cases/100,000 in 2011/2013), with higher rates among people with T2DM for all time periods. T2DM patients were older and had higher CCI values than T1DM and non-diabetic patients (CCI≥1, 31.4%, 20.4% and 21.5%, respectively; P<0.05). Time trend analyses showed significant increases in infections, RTx-associated complications and rejection for all groups (all P values<0.05). Infection rates were greater in people with T2DM (20.8%) and T1DM (23.5%) than in non-diabetic people (18.7%; P<0.05). Time trend analyses (2002-2013) showed significant decreases in mortality during admission for RTx (OR 0.75, 95% CI 0.68-0.83). Diabetes was not associated with a higher in-hospital mortality (OR: 1.20, 95% CI 0.92-1.55).

INTERPRETATION

RTx rates were higher and increased over time at a higher rate among T2DM patients. Mortality decreased over time in all groups. Diabetes does not predict mortality during admission for RTx.

FUNDING

Instituto Salud Carlos III and URJC-Banco Santander.

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.

Association of metabolic syndrome with serum fibroblast growth factor 21 in kidney transplanted patients

INTRODUCTION

Fibroblast growth factor 21 (FGF21) is a metabolic regulator with multiple beneficial effects on glucose and lipid homeostasis and insulin sensitivity.

OBJECTIVES

The aim of this study was to investigate the relation between the serum level of FGF21 with and metabolic syndrome (MS) in kidney transplant recipients.

PATIENTS AND METHODS

We performed a cross-sectional study on 86 stable renal transplant recipients to detect possible relation between serum FGF21 level and MS during October 2014 and Mach 2015. Patients with past history of diabetes mellitus were excluded.

RESULTS

There were 43 patients in each group with and without MS. Totally, they were 52 (60.5%) male and 34 (39.5%) female. The mean age of the MS group was significantly higher than that of non-MS group. There was not significant difference between mean serum creatinine level and glomerular filtration rate (GFR) between two groups (P > 0.05). The MS patients had higher weight and body mass index (BMI) (P < 0.05). The prevalence of BMI >25 kg/m(2) in MS group was 25 (58.8%) versus non-MS group that only 10 (23.3%) had this condition (P < 0.05). The mean of FGF21 level in MS and non-MS groups was 1.23 ± 0.67 ng/l and 1.18 ± 0.71 ng/l, respectively (P > 0.05). There was not significant difference of serum FGF21 level between MS and non-MS patients (P > 0.05).

CONCLUSION

While the elevated serum FGF21 level was found in subjects with insulin resistant states, however, this study revealed that serum FGF21 levels were not significantly increased in renal transplanted recipients with MS as compared with non-MS group.

Body mass index: short- and long-term impact on kidney transplantation

AIM

The topic of pretransplantation body mass index (BMI) is still a matter of controversy. The aim of this study was to investigate the influence of pretransplant BMI on short- and long-term outcomes in patients receiving kidney transplant.

METHODS

We have analysed 521 renal transplant recipients (RTRs). BMI was categorised as follows: less than or equal to 20, more than 20 to less than or equal to 25, more than 25 to less than or equal to 30 and more than 30 RESULTS: The distribution of the RTRs per category of BMI at baseline was: ≤ 20 (14.4%), > 20 to ≤ 25 (50.9%), > 25 ≤ 30 (26.9%) and > 30 (7.9%). In further analysis, the patients were stratified into four groups according to their pretransplant BMI values. There was no difference in the rates of delayed graft function between the four analysed groups of patients. Recipients with normal pre-transplant BMI were less likely to develop wound complications in comparison to the recipients with high BMI (p = 0.04) and obese recipients (p = 0.0001). RTRs with normal BMI were less likely to develop lymphoceles in comparison to the recipients with high BMI (p = 0.0003). Obese patients were more likely to develop lymphocele in comparison to the recipients with high BMI (p = 0.01). Obese recipients had a longer mean length of hospital stay in comparison to the recipients with normal BMI (p = 0.04). There was no significant difference regarding 1-year graft and patient survival, as well as because of acute rejection crisis between the investigated groups of recipients. We did not find any significant difference in 5-year patients and graft survival between those RTRs with BMI > 20 to ≤ 25 and to those recipients with BMI > 25.

CONCLUSION

Overweight and obese transplant candidates should not be excluded from kidney transplantation.

Moderator's view: Pretransplant weight loss in dialysis patients: cum grano salis

A high Body Mass Index (BMI) predicts delayed graft function, all cause and cardiovascular death after transplantation but such risk excess is apparently confined to patients included in studies performed before 2000. Perhaps with the exception of morbid obesity (BMI > 40), clinical outcomes in transplanted obese patients are definitely better than in listed dialysis patients who don't receive a renal transplant. Furthermore the new Scientific Registry of Transplant Recipients (SRTR) risk calculator incorporates BMI into the prediction model of the global risk for the graft's and patient's survival appropriately framing the risk of obesity in a multidimensional risk context. In the aggregate, available knowledge suggests that clinical decisions on weight loss before transplantation should be context specific. Renal transplant patients from living donors have substantial better survival in comparison to well matched dialysis patients listed for the same intervention at all BMI categories. Therefore renal transplantation in obese patients with a living donor may be prioritized. The attitude of fully informed obese patients at accepting the risk driven by transplantation, the experience of the surgical team with obese patients (including also robotic surgery) are of obvious importance. Renal transplantation should be timely considered when reasonable attempts at weight loss failed or appear overtly unrealistic. Transplantation in morbidly obese patients with BMI > 40, a category where the survival advantage of transplantation vs dialysis is probably small and still uncertain, particularly so in African-Americans, should be deferred until significant weight loss is achieved.

Renal transplantation in obese patients: experience in an Argentine center

Possible complications of renal transplants in obese patients have raised concerns among nephrologists. We describe the outcomes of 110 renal transplant patients according to body mass index (BMI). Recipient BMI was calculated by using height and weight at time of transplantation and categorized according to World Health Organization guidelines. The patients' BMI values were as follows: underweight, n = 8 (7.27%); normal weight, n = 55 (50%); overweight, n = 30 (27.27%); and obese, n = 17 (15.45%). Mean age was significantly different among groups: underweight, 27.62 ± 7.57 years; normal weight, 44.98 ± 15.55 years; overweight, 50.53 ± 13.90 years; and obese, 52.11 ± 10.41 years (P < .05). Donor age and mean time of dialysis treatment were comparable in all groups. Underweight patients had a significantly larger proportion of living donors than those with higher BMIs. Calculated glomerular filtration rate (using the Modification of Diet in Renal Disease equation) were significantly different among the groups at 30, 60, and 90 days' posttransplantation. At 180 days, however, it was comparable: underweight, 62.96 ± 40.77 mL/min/1.73 m(2); normal weight, 53.55 ± 26.23 mL/min/1.73 m(2); overweight, 47.52 ± 16.37 mL/min/1.73 m(2); and obese, 46.19 ± 17.56 mL/min/1.73 m(2) (P = .34). Incidence of delayed graft function was as follows: underweight, 0%; normal weight, 30.4%; overweight, 53.3%; and obese, 64.1% (P < .05). The incidence of surgical complications, incidence of rejection within the first 6 months' posttransplantation, and graft and patient survival rates over 6 months did not differ among the groups. Because transplantation in obese patients may be associated with higher risks and costs, the evaluation of each center experience is imperative. Longer term assessments are warranted, but our short-term results show that outcomes in overweight or obese renal transplant patients are comparable to those in patients with lower BMI.

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.

Body mass index and outcome in renal transplant recipients: a systematic review and meta-analysis

BACKGROUND

Whether overweight or obese end stage renal disease (ESRD) patients are suitable for renal transplantation (RT) is often debated. The objective of this review and meta-analysis was to systematically investigate the outcome of low versus high BMI recipients after RT.

METHODS

Comprehensive searches were conducted in MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and CENTRAL (the Cochrane Library 2014, issue 8). We reviewed four major guidelines that are available regarding (potential) RT recipients. The methodology was in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and written based on the PRISMA statement. The quality assessment of studies was performed by using the GRADE tool. A meta-analysis was performed using Review Manager 5.3. Random-effects models were used.

RESULTS

After identifying 5,526 studies addressing this topic, 56 studies were included. We extracted data for 37 outcome measures (including data of more than 209,000 RT recipients), of which 26 could be meta-analysed. The following outcome measures demonstrated significant differences in favour of low BMI (<30) recipients: mortality (RR = 1.52), delayed graft function (RR = 1.52), acute rejection (RR = 1.17), 1-, 2-, and 3-year graft survival (RR = 0.97, 0.95, and 0.97), 1-, 2-, and 3-year patient survival (RR = 0.99, 0.99, and 0.99), wound infection and dehiscence (RR = 3.13 and 4.85), NODAT (RR = 2.24), length of hospital stay (2.31 days), operation duration (0.77 hours), hypertension (RR = 1.35), and incisional hernia (RR = 2.72). However, patient survival expressed in hazard ratios was in significant favour of high BMI recipients. Differences in other outcome parameters were not significant.

CONCLUSIONS

Several of the pooled outcome measurements show significant benefits for 'low' BMI (<30) recipients. Therefore, we postulate that ESRD patients with a BMI >30 preferably should lose weight prior to RT. If this cannot be achieved with common measures, in morbidly obese RT candidates, bariatric surgery could be considered.

Obesity and organ transplantation: successes, failures, and opportunities

The increasing rate of societal obesity is also affecting the transplant world through obesity in candidates and donors as well as its posttransplant repercussions. Being overweight and obese has been shown to have significant effects on both short- and long-term complications as well as patient and graft survival. However, much of the comorbidity can be controlled or prevented with careful patient selection and aggressive management. A team approach to managing obesity and its comorbidities both pre- and posttransplant is essential for successful transplant outcomes. Complicating understanding the results of obesity research is the inclusion different weight categories, use of listing vs transplant weights, patient populations large enough for statistical power, and changes in transplant management, especially immunosuppression protocols, anti-infection protocols, and operative techniques. Much more research is needed regarding many elements, including safe weight loss before transplantation, prevention of weight gain after transplant, genomic influences, and the role of bariatric surgery in the transplant process.

Renal transplantation: better fat than thin

BACKGROUND

Obesity has been a relative contraindication for renal transplantation. This study evaluates the impact of pretransplant body mass index (BMI) on renal transplant outcomes in a single institution in the era of modern immunosuppression.

MATERIALS AND METHODS

A 10-y retrospective analysis was undertaken of 454 consecutive patients who received a renal transplant at Westmead Hospital from January 1, 2001 to December 31, 2010. The role of pretransplant BMI on patient survival, graft survival, surgical complications, and postoperative complications was studied.

RESULTS

The mean age of transplant of this study population was 45.4 ± 13.0 y. Live donation rate was 53.5%, and 60.6% were male. The median preoperative BMI was 25.6 (range, 14.3-51.4). One-year and 5-y patient survival were 97.4% and 86.6%, respectively, whereas 1-y and 5-y death-censored graft survival were 97.1% and 91.9%, respectively. Patients with BMI >30 did not exhibit any significant difference in survival or graft failure but had higher surgical wound infection rates (hazard ratio 3.95, P < 0.01). Patients with preoperative BMI <18.5 were associated with a six-fold increase in both death and death-censored graft failure (P < 0.01).

CONCLUSIONS

Pretransplant obesity increases wound infection but is not a contraindication to renal transplantation. Future prospective studies are required to further define the impact of low preoperative BMI <18.5.

Obesity, metabolic syndrome and diabetes mellitus after renal transplantation: prevention and treatment

The prevalence of the metabolic syndrome in dialysis patients is high and further increases after transplantation due to weight gain and the detrimental metabolic effects of immunosuppressive drugs. Corticosteroids cause insulin resistance, hyperlipidemia, abnormal glucose metabolism and arterial hypertension. The calcineurin inhibitor tacrolimus is diabetogenic by inhibiting insulin secretion, whereas cyclosporine causes hypertension and increases cholesterol levels. Mtor antagonists are responsible for hyperlipidemia and abnormal glucose metabolism by mechanisms that also implicate insulin resistance. The metabolic syndrome in transplant recipients has numerous detrimental effects such as increasing the risk of new onset diabetes, cardiovascular disease events and patient death. In addition, it has also been linked with accelerated loss of graft function, proteinuria and ultimately graft loss. Prevention and management of the metabolic syndrome are based on increasing physical activity, promotion of weight loss and control of cardiovascular risk factors. Bariatric surgery before or after renal transplantation in patients with body mass index >35 kg/m(2) is an option but its long term effects on graft and patient survival have not been investigated. Steroid withdrawal and replacement of tacrolimus with cyclosporine facilitate control of diabetes, whereas replacement of cyclosporine and mtor antagonists can improve hyperlipidemia. The new costimulation inhibitor belatacept has potent immunosuppressive properties without metabolic adverse effects and will be an important component of immunosuppressive regimens with better metabolic risk profile. Medical treatment of cardiovascular risk factors has to take potential drug interactions with immunosuppressive medication and drug accumulation due to renal insufficiency into account.

Obesity in kidney transplantation

Kidney transplantation is the preferred modality of renal replacement therapy. Long-term patient and graft survival have only improved marginally over the recent decade, mainly because of the development of cardiovascular disease after transplantation. Obesity is a risk factor for cardiovascular disease and is common before and after transplantation. This article reviews the literature assessing the role of pre- and post-transplant obesity on patient and graft survival, discusses the underlying obesity-related mechanisms leading to inferior kidney transplant outcomes, and explores the role of nutritional intervention on improving long-term outcomes of transplantation. Although the role of pretransplant obesity remains uncertain, post-transplant obesity increases the risk of graft failure and mortality. Nutritional intervention is effective in achieving post-transplant weight loss, but the effect on long-term outcomes has not been established. Future research should focus on conducting nutritional intervention studies aiming to improve long-term outcomes of kidney transplantation.

The survival benefit of kidney transplantation in obese patients

Obese patients have a decreased risk of death on dialysis but an increased risk of death after transplantation, and may derive a lower survival benefit from transplantation. Using data from the United States between 1995 and 2007 and multivariate non-proportional hazards analyses we determined the relative risk of death in transplant recipients grouped by body mass index (BMI) compared to wait-listed candidates with the same BMI (n = 208 498). One year after transplantation the survival benefit of transplantation varied by BMI: Standard criteria donor transplantation was associated with a 48% reduction in the risk of death in patients with BMI ≥ 40 kg/m(2) but a ≥ 66% reduction in patients with BMI < 40 kg/m2. Living donor transplantation was associated with ≥ 66% reduction in the risk of death in all BMI groups. In sub-group analyses, transplantation from any donor source was associated with a survival benefit in obese patients ≥ 50 years, and diabetic patients, but a survival benefit was not demonstrated in Black patients with BMI ≥ 40 kg/m(2). Although most obese patients selected for transplantation derive a survival benefit, the benefit is lower when BMI is ≥ 40 kg/m(2), and uncertain in Black patients with BMI ≥ 40 kg/m(2).