High Body Mass Index and Posttransplant Weight Gain Are Not Risk Factors for Kidney Graft and Patient Outcome

Effect of Recipient Body Mass Index on Kidney Transplantation Outcomes: A Systematic Review and Meta-analysis by the Transplant Committee from the French Association of Urology

CONTEXT

The impact of recipient obesity on kidney transplantation (KT) outcomes remains unclear.

OBJECTIVE

The aim of this study was to perform a systematic review and meta-analysis to appraise all available evidence on the outcomes of KT in obese patients (body mass index [BMI] ≥30 kg/m2) versus nonobese patients (BMI <30 kg/m2).

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed. Search was conducted in the MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and Cochrane databases to identify all studies reporting the outcomes of KT in obese versus nonobese recipients.

EVIDENCE SYNTHESIS

Fifty-two articles met the inclusion criteria. Delayed graft function and surgical complications were significantly higher in obese recipients (delayed graft function: relative risk [RR]: 1.44, 95% confidence interval [CI]: 1.32-1.57, p < 0.01; surgical complications: RR: 1.74, 95% CI: 1.36-2.22, p < 0.0001). Five-year patient survival (RR: 0.96, 95% CI: 0.92-1.00, p = 0.01), 10-yr patient survival (RR: 0.90, 95% CI: 0.84-0.97, p = 0.006), and 10-yr graft survival (RR: 0.87, 95% CI: 0.79-0.96, p = 0.01) were significantly inferior in the obese group.

CONCLUSIONS

KT in obese recipients was associated with lower patient and graft survival, and higher delayed graft function, acute rejection, and medical and surgical complications than nonobese recipients. In the current situation of organ shortage and increasing prevalence of obesity, ways to optimize KT in this setting should be investigated.

PATIENT SUMMARY

Compared with nonobese population, kidney transplantation in obese recipients has inferior patient and graft survival, and higher medical and surgical complications.

Obesity Affects Short-Term Renal Function After Renal Transplantation

BACKGROUND

The literature has shown a significant association between body mass index (BMI) and patient and graft outcomes after renal transplantation. The purpose of this study was to reveal the effect of obesity on graft function in a Taiwanese kidney transplant cohort.

METHODS

Two hundred consecutive patients who received kidney transplantation were enrolled in our study. Eight pediatric cases were excluded due to differing definitions of BMI among children. According to the national obesity criteria, these patients were divided into underweight, normal, overweight, and obese groups. Their estimated glomerular filtration rate (eGFR) was compared accordingly using t tests. Cumulative graft and patient survivals were calculated using Kaplan-Meier analysis. A P value of ≤ .05 was considered significant.

RESULTS

The mean age of our cohort (105 men and 87 women) was 45.3 years. There was no significant difference comparing biopsy-proven acute rejection, acute tubular necrosis, and delayed graft function between the obese and nonobese groups (P values: .293, .787, and .304, respectively). Short-term eGFR was inferior in the overweight group, but this effect was insignificant beyond 1 month. The 1-month and 3-month eGFR were found to be correlated with BMI groups (P = .012 and P = .008, respectively) but not significant after 6 months post-kidney transplantation.

CONCLUSIONS

Our study found that short-term renal function was affected by obesity and being overweight, possibly due to the higher prevalence of diabetes and dyslipidemia in obese patients and the increased surgical difficulty.

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.

Effects of Body Mass Index Changes In Pediatric Kidney Transplant Patients

BACKGROUND

The negative effects of pretransplant obesity and post-transplant body mass index (BMI) increase on graft survival have been reported in recent years. The aim of this study is to evaluate the effects of BMI changes on post-transplant graft function, lipid profile, and blood pressure.

METHODS

The study included 133 pediatric patients transplanted between 1994 and 2019 in Ege University. BMI Z-scores (BMIZs) were calculated according to age and sex before and after transplantation using the World Health Organization criteria. Patients with BMIZs >+1 standard deviation (SD) were defined as overweight, and those with BMIZs >+2 SD were defined as obese: Group 1: Obese or overweight before transplantation; Group 2: Thin or normal weight before and 2 years after transplantation; and Group 3: Thin or normal weight before transplantation and obese or overweight 2 years after transplantation.

RESULTS

At the time of transplantation 8% of the patients were overweight, and 1% were obese. Overweight and obesity statistically significantly increased (31.6%) 2 years after renal transplantation (P = .001). Obese and overweight patients have lower high-density lipoprotein levels and were younger at the time of transplantation. Graft functions, lipid levels, and blood glucose levels of the groups were similar (P > .05). The only significant difference between the groups was that Group 1 patients were younger than Group 2.

CONCLUSIONS

Obesity develops at a significant rate in pediatric patients after renal transplantation. In this study, we could not demonstrate negative effects of obesity and being overweight in terms of post-transplant graft function, lipid profile, blood glucose, and blood pressure.

Nonlinear relationship between body mass index and clinical outcomes after kidney transplantation: A dose-response meta-analysis of 50 observational studies

BACKGROUND

Exact dose-response relationship between body mass index at transplantation and clinical outcomes after kidney transplantation remained unclear, and no specific body mass index threshold and pretransplant weight loss aim were recommended for kidney transplantation candidates among transplant centers.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched for literature published up to December 31, 2019. The two-stage, random effect meta-analysis was performed to estimate the dose-response relationship between body mass index and clinical outcomes after kidney transplantation.

RESULTS

Ninety-four studies were included for qualitative assessment and 50 for dose-response meta-analyses. There was a U-shaped relationship between graft loss, patient death, and body mass index. Body mass index with the lowest risk of graft loss was 25.2 kg/m², and preferred body mass index range was 22-28 kg/m². Referring to a body mass index of 22 kg/m², the risk of graft loss was 1.088, 0.981, 1.003, and 1.685 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. Body mass index with the lowest risk of patient death was 24.7 kg/m², and preferred body mass index range was 22-27 kg/m². Referring to a body mass index of 22 kg/m², the patient death risk was 1.115, 0.981, 1.032, and 2.634 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. J-shaped relationships were observed between body mass index and acute rejection, delayed graft function, primary graft nonfunction, and de novo diabetes. Pair-wise comparisons showed that higher body mass index was also a risk factor for cardiovascular diseases, hypertension, infection, longer length of hospital stay, and lower estimated glomerular filtration rate level.

CONCLUSION

Underweight and severe obesity at transplantation are associated with a significantly increased risk of graft loss and patient death. A target body mass index at kidney transplantation is 22-27 kg/m².

A Nephrologist Perspective on Obesity: From Kidney Injury to Clinical Management

Obesity is one of the epidemics of our era. Its prevalence is higher than 30% in the U.S. and it is estimated to increase by 50% in 2030. Obesity is associated with a higher risk of all-cause mortality and it is known to be a cause of chronic kidney disease (CKD). Typically, obesity-related glomerulopathy (ORG) is ascribed to renal hemodynamic changes that lead to hyperfiltration, albuminuria and, finally, impairment in glomerular filtration rate due to glomerulosclerosis. Though not only hemodynamics are responsible for ORG: adipokines could cause local effects on mesangial and tubular cells and podocytes promoting maladaptive responses to hyperfiltration. Furthermore, hypertension and type 2 diabetes mellitus, two conditions generally associated with obesity, are both amplifiers of obesity injury in the renal parenchyma, as well as complications of overweight. As in the native kidney, obesity is also related to worse outcomes in kidney transplantation. Despite its impact in CKD and cardiovascular morbility and mortality, therapeutic strategies to fight against obesity-related CKD were limited for decades to renin-angiotensin blockade and bariatric surgery for patients who accomplished very restrictive criteria. Last years, different drugs have been approved or are under study for the treatment of obesity. Glucagon-like peptide-1 receptor agonists are promising in obesity-related CKD since they have shown benefits in terms of losing weight in obese patients, as well as preventing the onset of macroalbuminuria and slowing the decline of eGFR in type 2 diabetes. These new families of glucose-lowering drugs are a new frontier to be crossed by nephrologists to stop obesity-related CKD progression.

Changes in body mass index after pediatric renal transplantation

Significant weight gain following renal transplantation is common in adult and pediatric recipients and mostly depends on receiving higher doses of steroids, changes in mood and feelings, as well as their level of physical activities. This study was performed to evaluate body weight and body mass index (BMI) before and after kidney transplantation in children and adolescents. In this cross-sectional study, 71 pediatric renal transplant recipients (42 boys and 29 girls) were included. World Health Organization criteria were used for comparing Z-score BMI for age in our cases. Overweight was defined as Z-score BMI >+1 SD (standard deviation) and obesity as >+2 SD. At the time of transplantation, the mean age was 10.8 ± 3 years (5-16 years) and based on BMIZ-score, the patients were found to be thin (BMIZs <-2 SD) in 16.9%, normal (BMIZs = -2 to +1 SD) in 67.6%, overweight (>+1 SD to +2 SD) in 9.9%, and obese (BMIZs >+2 SD) in 5.6%.The mean follow-up duration after transplantation was 3.57 ± 1.68 years (1-7 years) and at the time of reevaluation after transplant, their mean age was 14.4 years (6-18 years). The mean BMI was 22 ± 5.3 kg/m², and for BMI grouping, the patients were thin in 7%, normal in 54.9%, overweight in 21.1%, and obese in 17%. Pretransplant thinness (BMIZs <-2 SD) was found in 12 patients (16.9%), equally in boys and girls, and in most of them (83.3%), BMIZs changed to normal or even >+1 SD after transplant. Chronic continuous decrease of glomerular filtration rate (CCD/GFR) was found in 27 cases (38%); 74.1% were male (P = 0.045), hypertriglyceridemia was found in 74.1% (P = 0.023%), hypercholesterolemia in 63% (P = 0.032),and obesity in 18.5% (p = 0.5). The incidence of obesity has tripled after kidney transplantation. It was not a risk factor for graft or patient survival in our experience, whereas pretransplant obesity had some effects on long-term graft outcome.

Weight change trajectories in Aboriginal and Torres Strait islander Australians after kidney transplantation: a cohort analysis using the Australia and New Zealand Dialysis and Transplant registry (ANZDATA)

Background

Weight change post-kidney transplantation and its associations in Aboriginal and Torres Strait Islander Australians, a group known to have poor patient and graft outcomes, are unknown. Weight change based on body mass index in Aboriginal and Torres Strait Islander Australian recipients was compared to non- indigenous recipients.

Methods

We performed a cohort analysis of data from the Australia and New Zealand Dialysis and Transplant Registry for first deceased donor kidney transplant recipients between 1995 and 2014 in Australia. Weight change post-kidney transplantation was analysed by recipient ethnicity using multivariate mixed effect linear regression analysis.

Results

There were 343 (5.24%) Aboriginal and Torres Strait Islander Australian kidney transplants recipients from a total of 6550 recipients. They had higher pre-transplant BMI (p < 0.001), higher rates of current smokers (p < 0.001), diabetes (p < 0.001), coronary artery disease (p < 0.001), cerebrovascular disease (p = 0.011) and peripheral vascular disease (p = 0.013), ≥4 HLA mismatches (p < 0.001), graft loss (p < 0.001), mortality (p < 0.001) and rejection rates (p < 0.001). Weight increased in the first 2 years post-transplantation in both Aboriginal and Torres Strait Islander Australians and non-indigenous Australians. After adjusting for the baseline differences, weight change diverged significantly at 6, 12 and 24 months. The difference was most marked between 6 and 12 months. When stratified by pre-transplantation BMI, all groups except underweight reflected this pattern. Normal weight and obese Aboriginal and Torres Strait Islander Australian recipients had substantial increase at 12 and 24 months and overweight at 6, 12 and 24 months.

The difference in BMI trajectories between Aboriginal and Torres Strait Islander Australians and non- indigenous Australian transplant recipients persisted after adjustment in multivariate mixed effect linear regression analysis.

Conclusions

Post-kidney transplantation weight gain in this high-risk population is substantial and greater than in non-indigenous Australians. Further studies should assess the effect of treatment factors and weight gain on transplant and recipient outcomes.

Obesity in pediatric kidney transplant recipients and the risks of acute rejection, graft loss and death

BACKGROUND

Obesity is prevalent in children with chronic kidney disease (CKD), but the health consequences of this combination of comorbidities are uncertain. The aim of this study was to evaluate the impact of obesity on the outcomes of children following kidney transplantation.

METHODS

Using data from the ANZDATA Registry (1994-2013), we assessed the association between age-appropriate body mass index (BMI) at the time of transplantation and the subsequent development of acute rejection (within the first 6 months), graft loss and death using adjusted Cox proportional hazards models.

RESULTS

Included in our analysis were 750 children ranging in age from 2 to 18 (median age 12) years with a total of 6597 person-years of follow-up (median follow-up 8.4 years). Overall, at transplantation 129 (17.2%) children were classified as being overweight and 61 (8.1%) as being obese. Of the 750 children, 102 (16.2%) experienced acute rejection within the first 6 months of transplantation, 235 (31.3%) lost their allograft and 53 (7.1%) died. Compared to children with normal BMI, the adjusted hazard ratios (HR) for graft loss in children who were underweight, overweight or diagnosed as obese were 1.05 [95% confidence interval (CI) 0.70-1.60], 1.03 (95% CI 0.71-1.49) and 1.61 (95% CI 1.05-2.47), respectively. There was no statistically significant association between BMI and acute rejection [underweight: HR 1.07, 95% CI 0.54-2.09; overweight: HR 1.42, 95% CI 0.86-2.34; obese: HR 1.83, 95% CI 0.95-3.51) or patient survival (underweight: HR 1.18, 95% CI 0.54-2.58, overweight: HR 0.85, 95% CI 0.38-1.92; obese: HR 0.80, 95% CI 0.25-2.61).

CONCLUSIONS

Over 10 years of follow-up, pediatric transplant recipients diagnosed with obesity have a substantially increased risk of allograft failure but not acute rejection of the graft or death.

Absence of the Effect of Pretransplant Body Mass Index on Post Kidney Transplant Outcomes

CONTEXT

Obesity has been reported as risk factor for reduced posttransplant graft and patient survival and increased delayed graft function (DGF).

OBJECTIVE

The purpose of this work is to analyze the effect of body mass index (BMI) on defined transplant outcomes in patients transplanted under defined guidelines in a kidney transplant program.

DESIGN

Review of a prospectively collected database in renal transplant recipients receiving rabbit antithymocyte globulin induction, mycophenolate mofetil, tacrolimus, and early corticosteroid withdrawal between 2001 and 2011.

SETTING

This review was conducted in a single abdominal transplant program in the United States.

MAIN OUTCOME MEASURES

Primary outcome was death-censored graft survival categorized by posttransplant body mass groups. Secondary outcomes included DGF as well as patient survival.

RESULTS

Four hundred sixty seven patients were identified. No difference was observed in graft survival or DGF between BMI groups. One-year, death-censored graft survival and patient survival rates ranged from 97.5% to 100% and 96.6% to 100%, respectively. Delayed graft function was uncommon across all BMI groups, ranging from 5.3% to 9.1%, with the lowest incidence in patients with a BMI ≥ 35 kg/m(2). Biopsy-proven acute rejection rates at 1 year were similar across all groups (10.1%-14%) as were estimated glomerular filtration rates were at 1, 3, and 5 years.

CONCLUSION

Our results do not show an effect of BMI on posttransplant outcomes, suggesting that relaxation of BMI criteria may be warranted for recipient selection.

Postoperative weight gain during the first year after kidney, liver, heart, and lung transplant: a prospective study

CONTEXT

Studies of all types of organ transplant recipients have suggested that weight gain, expressed as an increase in body mass index (BMI), after transplant is common.

OBJECTIVES

To describe weight gain during the first year after transplant and to determine risk factors associated with weight gain with particular attention to type of transplant.

DESIGN, SETTING, AND PARTICIPANTS

A prospective study of 502 consecutive organ transplant recipients (261 kidney, 73 liver, 29 heart, 139 lung) to identify patterns of BMI change. Measurements were made during regular outpatient clinical visits at 2, 6, and 12 months after transplant. Data were retrieved from patients' charts and correlated with maintenance corticosteroid doses.

RESULTS

Overall, mean BMI (SD; range) was 23.9 (4.5; 13.6-44.1) at 2 months and increased to 25.4 (4.0; 13.0-42.2) by the end of the first postoperative year. BMI levels organized by World Health Organization categories showed a trend toward overweight/obesity in kidney (53.4%), liver (51.5%), heart (51.7%), and lung (33.1%) patients by 12 months after transplant. BMI changed significantly (P= .05) for all organ types and between all assessment points, except in kidney recipients. Maintenance corticosteroid doses were not a predictor of BMI at 12 months after transplant for most patients.

CONCLUSIONS

Weight gain was common among patients undergoing kidney, liver, heart, and lung transplant; however, many showed BMI values close to normality at the end of the first year after transplant. In most cases, increased BMI levels were related to obesity before transplant and not to maintenance corticosteroid therapy.

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.

Effects of obesity on kidney transplantation outcomes: a systematic review and meta-analysis

BACKGROUND

The effects of obesity on outcomes reported after kidney transplantation have been controversial. The purpose of this systematic review and meta-analysis was to elucidate this issue.

METHODS

MEDLINE, EMBASE, Cochrane Library, and gray literature were searched up to August 6, 2013. Studies that compared obese and nonobese patients who underwent kidney transplantation and evaluated one of these outcomes-delayed graft function (DGF), acute rejection, graft or patient survival at 1 or 5 years after transplantation, or death by cardiovascular disease (CVD)-were included. Two independent reviewers extracted the data and assessed the quality of the studies.

RESULTS

From 1,973 articles retrieved, 21 studies (9,296 patients) were included. Obesity was associated with DGF (relative risk, 1.41; 95% confidence interval, 1.26-1.57; I=8%; Pheterogeneity=0.36), but not with acute rejection. Graft loss and death were associated with obesity only in the analysis of studies that evaluated patients who received a kidney graft before year 2000. No association of obesity with graft loss and death was found in the analysis of studies that evaluated patients who received a kidney graft after year 2000. Death by CVD was associated with obesity (relative risk, 2.07; 95% confidence interval, 1.17-3.64; I=0%; Pheterogeneity=0.59); however, most studies included in this analysis evaluated patients who received a kidney graft after year 2000.

CONCLUSION

In conclusion, obese patients have increased risk for DGF. In the past years, obesity was a risk factor for graft loss, death by CVD, and all-cause mortality. However, for the obese transplanted patient today, the graft and patient survival is the same as that of the nonobese patient.

Adiposity and cardiovascular disease risk factors in renal transplant recipients: Are there differences between sexes?

OBJECTIVE

The aim of this study was to evaluate high body adiposity and cardiovascular disease (CVD) risk factors prevalence, in renal transplant recipients (RTR), comparing men with women.

METHODS

In this retrospective cross-sectional study, 102 patients (55 men) who were 49 ± 1.2 y and 114.3 ± 9 mo post-transplant (post-tx) were evaluated. Pretransplant (pre-tx) period data and weight gain during the first year post-tx were obtained from patient charts and post-tx data were collected during a routine visit at nephrology clinic. Body mass index (BMI) ≥ 25 kg/m(2) defined overweight and BMI ≥ 30 kg/m(2) defined obesity.

RESULTS

Pre-tx overweight prevalence was low and similar between men and women (26%), whereas only women showed obesity (11%). Post-tx body weight increased significantly in the entire group, leading to an increase in overweight (to 38% in men and 51% in women) and obesity (to 11% in men and 23% in women) prevalence. Post-tx comparisons between men and women showed that women had higher (women versus men; P < 0.05) BMI values (26.7 ± 0.8 versus 24.7 ± 0.5 kg/m(2)), weight gain during first year post-tx (9.2 ± 1.1 versus 5.5 ± 1 kg), abdominal obesity (57% versus 23%) and diabetes (34% versus 16%) prevalence. The associations between adiposity and CVD risk factors showed that pre-tx overweight increased the risk for diabetes in post-tx; pos-tx high BMI and abdominal obesity increased the risk for metabolic syndrome; abdominal obesity increased the risk for dyslipidemia in women.

CONCLUSIONS

High body adiposity prevalence was high after transplantation and increased the risk for metabolic syndrome, an important CVD risk factor. Women showed higher total body adiposity values, abdominal obesity, and diabetes prevalence than men. Abdominal obesity increased the risk for dyslipidemia in women.

Kidney transplantation in the obese transplant candidates: to transplant or not to transplant?

The prevalence of obesity (body mass index ≥30 kg/m(2)) at the time of transplantation among kidney transplant recipients in the United States has doubled between 1987 and 2001 and continues to increase inexorably. Single-center and large registry studies in kidney transplant recipients demonstrated that high body mass index (BMI) at transplant is associated with increased risk of wound and surgical site infections, delayed graft function (DGF), acute rejection episodes, and graft loss, among others. Hence, in many centers, obese transplant candidates are denied a transplant based on their body mass index (BMI) alone. The impact of obesity on short- and long-term graft and patient outcomes after kidney transplantation are herein revisited, followed by the authors' proposed approach to evaluate and select obese transplant candidates for a kidney transplant. Suggested interventions to optimize the health of such candidates are also discussed.

The impact of recipient obesity on outcomes after renal transplantation

BACKGROUND

The benefit of renal transplantation in obese patients is controversial, with many centers setting upper limits on body mass index (BMI) in consideration for listing patients for transplant. This study was undertaken to determine the effect of recipient obesity on delayed graft function (DGF) and graft survival after renal transplantation.

METHODS

Retrospective review of all renal transplant recipients in the United Network for Organ Sharing database from January 1, 2004, through December 31, 2009, was performed. Primary endpoints were DGF and non-death-censored graft survival. Comparisons were made on the basis of the following weight classes: nonobese (BMI < 30), class I obese (30 ≤ BMI < 35), class II obese (35 ≤ BMI < 40), and class III obese (BMI ≥ 40).

RESULTS

Multivariable logistic regression indicated a significantly increased risk for DGF in obese patients. The odds ratios for DGF compared with nonobese patients were 1.34 [95% confidence interval (CI) 1.27-1.42; P < 0.001], 1.68 (95% CI 1.56-1.82; P < 0.001), and 2.68 (95% CI 2.34-3.07; P < 0.001) for the class I obese, class II obese, and class III obese groups, respectively. Class I obesity was not a significant risk for non-death-censored graft failure [hazard ratio (HR) 1.00, 95% CI 0.95-1.05; P = 0.901] compared with nonobese patients. Patients in the class II obese (HR 1.15, 95% CI 1.07-1.24; P < 0.001) and class III obese (HR 1.26, 95% CI 1.11-1.43; P < 0.001) groups were at a significantly increased risk for graft failure than their nonobese counterparts.

CONCLUSIONS

Obese patients in all weight classes are at an increased risk for DGF after renal transplantation, although differences in non-death-censored graft survival are such that transplantation should not be denied on the basis of BMI criteria alone.

Obesity and body composition for transplant wait-list candidacy--challenging or maintaining the BMI limits?

Most kidney transplantation programs have a maximum body mass index (BMI) above which they will not place a patient on the active waiting list. However, obesity is common among patients with end-stage renal disease (ESRD), and weight loss is difficult, resulting in many patients being denied the opportunity to be considered for a transplant. BMI limits are in place because of data that outcomes are worse among obese transplant recipients than among those with lower BMI. However, the data to suggest that patient and graft survival are affected by obesity are not consistent, and obese patients with ESRD have better survival after kidney transplantation compared with remaining on dialysis. Therefore, it is important to carefully examine the question of BMI limits to ensure that we are achieving the right balance and making the best use of donated kidneys.

Weight gain in long-term survivors of kidney or liver transplantation--another paradigm of sarcopenic obesity?

OBJECTIVE

Obesity in transplant recipients is a frequent phenomenon but data from body composition analyses in long-term survivors are limited. Body composition and energy metabolism were studied in patients after liver (LTX) and kidney (KTX) transplantation and patients with liver cirrhosis (LCI) or on chronic hemodialysis (HD) and compared to healthy controls.

METHODS

In 42 patients 50.0 mo (median; range 17.1-100.6) after LTX and 30 patients 93.0 mo (31.2-180.1) after KTX as wells as in LCI (n = 39) or HD (n = 10) patients mid-arm muscle and fat area, body cell mass, and phase angle (bioimpedance analysis), and resting energy expenditure (indirect calorimetry, REE(CALO)) were measured.

RESULTS

Obesity was more prevalent in LTX (17%) than LCI (3%) and in KTX (27%) than in HD (10%). In LTX and KTX, phase angle was higher than in end-stage disease (LTX 5.6° [4.1-7.2] versus LCI 4.4° [2.9-7.3], P < 0.001; KTX 5.9° [4.4-8.7] versus HD 4.3° [2.9-6.8]) but was lower in all patient groups than in controls (7.1°; 4.6-8.9; P < 0.001). In LCI and HD REE(CALO) was higher than predicted, while in LTX and KTX REE(CALO) was not different from predicted REE.

CONCLUSIONS

Despite excellent graft function, many long-term LTX or KTX survivors exhibit a phenotype of sarcopenic obesity with increased fat but low muscle mass. This abnormal body composition is observed despite normalization of the hypermetabolism found in chronic disease and cannot be explained by overeating. The role of appropriate nutrition and physiotherapy after transplantation merits further investigation.

Measuring the rate of weight gain and the influential role of diet in patients undergoing elective laparoscopic cholecystectomy: a 6-month follow-up study

Weight gain after cholecystectomy is one of the major surgical problems consistent with morbidities and long-term mortalities. Here, we aimed to study the impact of palliative cholecystectomy on weight gain and nutritional status of the patients before and in 1, 4 and 6 months after surgery. We performed a prospective survey on a cohort of 48 patients undergoing elective cholecystectomy. The nutritional status of the patients was collected by nutrition nurse and analysed by NutriBase software. There were 13 (16%) females and 35 (84%) males with the mean age of 51.8 ± 1.97. In 6 months after surgery, patients had higher values of BMI, daily energy expenditure, carbohydrate and lipid consumption and a decreased level of protein consumption. Weight gain after surgery was caused by an increase in fat consumption which resulted in the weight gain and worsening of lipid profile. Dietary consultation, shortly after surgery, would improve patient outcome after cholecystectomy.

Leptin, insulin resistance, and metabolic changes 5 years after renal transplantation

OBJECTIVE

To evaluate leptin, insulin resistance (IR), and changes in body composition and lipid profile within 5 years after renal transplantation.

DESIGN

Longitudinal study.

SETTING

Hospital de Clínicas de Porto Alegre/RS, Brazil.

SUBJECTS

Thirty-two renal transplant recipients were followed up for 5 years after transplantation.

METHODS

Data were collected at transplantation time (T₁) and after 3 months (T₂), 1 year (T₃), and 5 years (T₄). Leptin serum levels, IR assessed by homeostasis model assessment (HOMA) index, lipid profile, and anthropometric measurements were analyzed. Data were compared with a control group at baseline.

RESULTS

At T₁, pretransplant patients had leptin levels (ng/mL) (11.9 [9.2 to 25.2]) higher than the control group (7.7 [5.2 to 9.9]; P < .0001). After transplantation, levels decreased at T₂ and T₃, but increased at T₄ to values similar to those seen at T₁ (T₄: 9.2 [5.7 to 21]; P = 1). HOMA also decreased at T₂, but increased at T₄ to identical levels (T₁: 2.1 [1.63 to 2.23], T₄: 2.1 [1.6 to 2.85]; P = 1). No significant changes in body fat percentage (BF%) were observed; however, the arm muscle circumference increased significantly at T₄ (P < .0001). At T₂, total cholesterol, triglycerides, and low-density lipoprotein cholesterol increased, whereas at T₄, lipid profile moved toward T₁ levels. By linear regression analysis, gender, BF%, and HOMA were independent predictors of leptin levels. A trend toward higher body mass index was observed in woman who also presented higher leptin and lower HOMA levels.

CONCLUSION

Leptin levels and HOMA decrease in the immediate posttransplant period and remain reduced for at least 1 year. Five years post transplantation, leptin, IR, BF%, and lipids have a profile similar to those in the pretransplant period. This metabolic profile is possibly associated with the elevated incidence of cardiovascular diseases observed in the late posttransplant period.

Higher recipient body mass index is associated with post-transplant delayed kidney graft function

To examine whether a higher body mass index (BMI) in kidney recipients is associated with delayed graft function (DGF), we analyzed data from 11,836 hemodialysis patients in the Scientific Registry of Transplant Recipients who underwent kidney transplantation. The patient cohort included women, blacks, and diabetics; the average age was 49 years; and the mean BMI was 26.8 kg/m(2). After adjusting for relevant covariates, multivariate logistic regression analyses found that one standard deviation increase in pretransplant BMI was associated with a higher risk of DGF (odds ratio (OR) 1.35). Compared with patients with a pretransplant BMI of 22-24.99 kg/m(2), overweight patients (BMI 25-29.99 kg/m(2)), mild obesity patients (BMI 30-34.99 kg/m(2)), and moderate-to-severe obesity patients (BMI 35 kg/m(2) and over) had a significantly higher risk of DGF, with ORs of 1.30, 1.42, and 2.18, respectively. Similar associations were found in all subgroups of patients. Hence, pretransplant overweight or obesity is associated with an incrementally higher risk of DGF.

Associations of body mass index and weight loss with mortality in transplant-waitlisted maintenance hemodialysis patients

A body mass index (BMI) below morbid obesity range is often a requirement for kidney transplant wait-listing, but data linking BMI changes to mortality during the waitlist period are lacking. By linking the 6-year (7/2001-6/2007) national databases of a large dialysis organization and the Scientific Registry of Transplant Recipients, we identified 14 632 waitlisted hemodialysis patients without kidney transplantation. Time-dependent survival models examined the mortality predictability of 13-week-averaged BMI, pretransplant serum creatinine as a muscle mass surrogate and their changes over time. The patients were on average 52 ± 13 years old, 40% women and had a BMI of 26.9 ± 6.3 kg/m². Each kg/m² increase of BMI was associated with a death hazard ratio (HR) of 0.96 (95%CI: 0.95-0.97). Compared to the lowest creatinine quintile, the 4th and 5th quintiles had death HRs of 0.75 (0.66-0.86) and 0.57 (0.49-0.66), respectively. Compared to minimal (< ± 1 kg) weight change over 6 months, those with 3 kg- < 5 kg and ≥ 5 kg weight loss had death HRs of 1.31 (1.14-1.52) and 1.51 (1.30-1.75), respectively. Similar associations were observed with creatinine changes over time. Transplant-waitlisted hemodialysis patients with lower BMI or muscle mass and/or unintentional weight or muscle loss have higher mortality in this observational study. Impact of intentional weight change remains unclear.

Associations of pretransplant weight and muscle mass with mortality in renal transplant recipients

BACKGROUND AND OBJECTIVES

The association between pretransplant body composition and posttransplant outcomes in renal transplant recipients is unclear. It was hypothesized that in hemodialysis patients higher muscle mass (represented by higher pretransplant serum creatinine level) and larger body size (represented by higher pretransplant body mass index [BMI]) are associated with better posttransplant outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Linking 5-year patient data of a large dialysis organization (DaVita) to the Scientific Registry of Transplant Recipients, 10,090 hemodialysis patients were identified who underwent kidney transplantation from July 2001 to June 2007. Cox regression hazard ratios and 95% confidence intervals of death and/or graft failure were estimated.

RESULTS

Patients were 49 ± 13 years old and included 49% women, 45% diabetics, and 27% African Americans. In Cox models adjusted for case-mix, nutrition-inflammation complex, and transplant-related covariates, the 3-month-averaged postdialysis weight-based pretransplant BMI of 20 to <22 and < 20 kg/m(2), compared with 22 to <25 kg/m(2), showed a nonsignificant trend toward higher combined posttransplant mortality or graft failure, and even weaker associations existed for BMI ≥ 25 kg/m(2). Compared with pretransplant 3-month- averaged serum creatinine of 8 to <10 mg/dl, there was 2.2-fold higher risk of combined death or graft failure with serum creatinine <4 mg/dl, whereas creatinine ≥14 mg/dl exhibited 22% better graft and patient survival.

CONCLUSIONS

Pretransplant obesity does not appear to be associated with poor posttransplant outcomes. Larger pretransplant muscle mass, reflected by higher pretransplant serum creatinine level, is associated with greater posttransplant graft and patient survival.

Steroids and poor nutrition are associated with infectious wound complications in children undergoing first stage procedures for ulcerative colitis

BACKGROUND

Risk factors for postoperative infections have not been evaluated in pediatric patients with ulcerative colitis (UC). This review was undertaken to evaluate the effects of immunosuppressive therapy and other preoperative factors on infectious wound complications in children undergoing first stage surgical therapy for UC.

METHODS

A 10-year retrospective review of children under 18 years of age receiving first stage surgical therapy for UC at a major children's hospital was performed. Preoperative clinical and treatment variables were identified and correlated with postoperative wound complications.

RESULTS

A total of 51 children were identified: 19 underwent colectomy with ileo-anal-pouch anastomosis and 32 underwent total abdominal colectomy with Hartmann's pouch. A total of 20 infectious complications were identified in 18 patients. Preoperative steroid use was associated with a greater postoperative wound infection rate. Preoperative hemoglobin less than 10 g/dL (P < .05) and albumin less than 3 g/dL (P = 0.1) were associated with greater rates of postoperative infection. Preoperative body mass index and other immunosuppressive agents did not influence postoperative infectious morbidity.

CONCLUSIONS

The majority of pediatric patients who require operative intervention for UC are debilitated from their disease and medication use. Children with normal serum albumin and hemoglobin who are not on steroid therapy have a low risk of postoperative infectious complications.