Obesity and renal transplant outcome: a report of the North American Pediatric Renal Transplant Cooperative Study

Rapid Weight Gain After Pediatric Kidney Transplant and Development of Cardiometabolic Risk Factors Among Children Enrolled in the North American Pediatric Renal Trials and Collaborative Studies Cohort

INTRODUCTION

Given the risks of cardiovascular disease among pediatric kidney transplant recipients, we evaluated whether there was an association between rapid weight gain (RWG) following kidney transplantation and the development of obesity and hypertension among children enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) registry.

METHODS

This retrospective analysis of the NAPRTCS transplant cohort assessed for RWG in the first year post-transplant and evaluated for obesity and hypertension in children with and without RWG up to 5 years post-transplant. We evaluated three separate eras (1986-1999, 2000-2009, and 2010-2021). We performed chi-square and logistic regression analyses to assess cardiometabolic risk at three time points (1, 3, and 5 years post-transplant).

RESULTS

The percent of children with RWG decreased across the three eras (1986-1999 37.3%, 2000-2009 23.0%, and 2010-2021 16.4%). Obesity was significantly more common among children with a history of RWG following transplant, with 48%-67% with RWG having obesity 5 years following transplant compared with 22%-25% without RWG. Hypertension was significantly more common in the RWG group than the non-RWG group at all but two time points. In logistic regression models, the odds of obesity in the RWG group compared with non-RWG was 2.55 (2.29-2.83), and the odds of hypertension were 1.00 (0.94-1.08). Steroid minimization protocols were associated with significantly less RWG.

CONCLUSIONS

RWG was significantly associated with obesity but not hypertension among pediatric kidney transplant recipients enrolled in NAPRTCS. Interventions targeting RWG following kidney transplant should be evaluated as a potential way to modify obesity rates following transplantation.

Body mass index in pediatric kidney transplant selection criteria

BACKGROUND

Obesity is associated with increased complications, rejection, and graft loss after kidney transplantation in adult and pediatric recipients. Elevated body mass index (BMI) is a common contraindication to transplant at adult kidney transplant programs; however, there is no data on such limitations for pediatric patients.

METHODS

Between October and December 2022, we conducted a survey of Pediatric Nephrology Research Consortium centers assessing the use of BMI in pediatric kidney transplant evaluation. Centers reporting utilization of BMI cutoffs were invited to submit patient-level data on children declined for active transplant listing due to BMI.

RESULTS

Thirty-nine centers responded to the survey (42% response rate); 51% include BMI in their written listing criteria, with a median BMI "cutoff" of 39 kg/m2 (range 30-50 kg/m2). Between January 1, 2016, and December 31, 2021, 30 children at 15 transplant centers were declined for listing status due to BMI. Patient-level data was provided for 19 children (63%) who were denied active listing status; median BMI was 42 kg/m2 (range 35.8-49.4 kg/m2) and 84% were on dialysis. One year after evaluation, seven patients (37%) had proceeded to active wait list status. Eight (42%) remained in inactive status and four (21%) were unlisted; ten of these 12 patients (83%) were on dialysis.

CONCLUSIONS

The use of BMI in pediatric kidney transplant evaluation and listing varies among centers, but BMI limits access to transplant for some children. More information is needed on the outcomes of obese pediatric kidney candidates who are and are not transplanted, to guide development of national and international consensus.

Role of Nutrients in Pediatric Non-Dialysis Chronic Kidney Disease: From Pathogenesis to Correct Supplementation

Nutrition management is fundamental for children with chronic kidney disease (CKD). Fluid balance and low-protein and low-sodium diets are the more stressed fields from a nutritional point of view. At the same time, the role of micronutrients is often underestimated. Starting from the causes that could lead to potential micronutrient deficiencies in these patients, this review considers all micronutrients that could be administered in CKD to improve the prognosis of this disease.

Safety and utility of panniculectomy in renal transplant candidates and end stage renal disease patients

BACKGROUND

As the obesity crisis in the United States continues, some renal transplantation centers have liberalized their BMI criteria necessary for transplant eligibility. More individuals with larger body-habitus related comorbidities with End-Stage Renal Disease (ESRD) now qualify for renal transplantation (RT). Surgical modalities from other fields also interact with this patient population.

METHODS

In order to assess surgical outcomes of panniculectomy in the context of renal transplantation and ESRD, the authors performed a systematic review following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) 2020 guidelines. Due to a paucity of existing primary studies, we retrospectively collected data on patients with ESRD undergoing panniculectomy from the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) to evaluate outcomes of body contouring in this patient population.

RESULTS

From the systematic review, a total of 783 ESRD patients underwent panniculectomy among the studies identified. Of these, 91 patients underwent panniculectomy simultaneously to RT while 692 had their pannus resected prior to kidney transplant. The most common complication was hematoma followed by wound dehiscence. From the NSQIP database, 24 868 patients met the inclusion criteria for analysis. In the setting of renal transplant status, patients with diabetes, hypertension requiring medication, and requiring dialysis were more likely to suffer postoperative complications (OR 1.31, 1.15, and 2.2, respectively). However, upon sub-analysis of specific types of complications, the only retained association was between diabetes and wound complication.

CONCLUSION

Preliminary data show that panniculectomy in ESRD patients appears to be safe, though with a nominal increased risk for complications. Pannus resection does not appear to impact post-transplantation outcomes, including long-term allograft survival. Larger, higher powered, randomized studies are needed to confirm the safety, utility, and medical benefit of panniculectomy in the context of renal transplantation.

Malnutrition Patterns in Children with Chronic Kidney Disease

Malnutrition is frequent in children with chronic kidney disease (CKD). Apart from undernutrition and protein energy wasting (PEW), overnutrition prevalence is rising, resulting in fat mass accumulation. Sedentary behavior and unbalanced diet are the most important causal factors. Both underweight and obesity are linked to adverse outcomes regarding renal function, cardiometabolic risk and mortality rate. Muscle wasting is the cornerstone finding of PEW, preceding fat loss and may lead to fatigue, musculoskeletal decline and frailty. In addition, clinical data emphasize the growing occurrence of muscle mass and strength deficits in patients with fat mass accumulation, attributed to CKD-related wasting processes, reduced physical activity and possibly to obesity-induced inflammatory diseases, leading to sarcopenic obesity. Moreover, children with CKD are susceptible to abdominal obesity, resulting from high body fat distribution into the visceral abdomen compartment. Both sarcopenic and abdominal obesity are associated with increased cardiometabolic risk. This review analyzes the pathogenetic mechanisms, current trends and outcomes of malnutrition patterns in pediatric CKD. Moreover, it underlines the importance of body composition assessment for the nutritional evaluation and summarizes the advantages and limitations of the currently available techniques. Furthermore, it highlights the benefits of growth hormone therapy and physical activity on malnutrition management.

An ethical analysis of obesity as a contraindication of pediatric kidney transplant candidacy

The inclusion of body mass index (BMI) as a criterion for determining kidney transplant candidacy in children raises clinical and ethical challenges. Childhood obesity is on the rise and common among children with kidney failure. In addition, obesity is reported as an independent risk factor for the development of CKD and kidney failure. Resultantly, more children with obesity are anticipated to need kidney transplants. Most transplant centers around the world use high BMI as a relative or absolute contraindication for kidney transplant. However, use of obesity as a relative or absolute contraindication for pediatric kidney transplant is controversial. Empirical data demonstrating poorer outcomes following kidney transplant in obese pediatric patients are limited. In addition, pediatric obesity is distributed inequitably among groups. Unlike adults, most children lack independent agency to choose their food sources and exercise opportunities; they are dependent on their families for these choices. In this paper, we define childhood obesity and review (1) the association and impact of obesity on kidney disease and kidney transplant, (2) existing adult guidelines and rationale for using high BMI as a criterion for kidney transplant, (3) the prevalence of childhood obesity among children with kidney failure, and (4) the existing literature on obesity and pediatric kidney transplant outcomes. We then discuss ethical considerations related to the use of obesity as a criterion for kidney transplant.

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.

Malnutrition and immune cell subsets in children undergoing kidney transplantation

BACKGROUND

Malnutrition, including obesity and undernutrition, among children is increasing in prevalence and is common among children on renal replacement therapy. The effect of malnutrition on the pre-transplant immune system and how the pediatric immune system responds to the insult of both immunosuppression and allotransplantation is unknown. We examined the relationship of nutritional status with post-transplant outcomes and characterized the peripheral immune cell phenotypes of children from the Immune Development of Pediatric Transplant (IMPACT) study.

METHODS

Ninety-eight patients from the IMPACT study were classified as having obesity, undernutrition, or normal nutrition-based pre-transplant measurements. Incidence of infectious and alloimmune outcomes at 1-year post-transplantation was compared between nutritional groups using Gray's test and Fine-Gray subdistribution hazards model. Event-free survival was estimated by Kaplan-Meier method and compared between groups. Differences in immune cell subsets between nutritional groups over time were determined using generalized estimating equations accounting for the correlation between repeated measurements.

RESULTS

We did not observe that nutritional status was associated with infectious or alloimmune events or event-free survival post-transplant. We demonstrated that children with obesity had distinct T-and B-cell signatures relative to those with undernutrition and normal nutrition, even when controlling for immunosuppression. Children with obesity had a lower frequency of CD8 Tnaive cells 9-month post-transplant (p < .001), a higher frequency of CD4 CD57 + PD1- T cells, and lower frequencies of CD57-PD1+ CD8 and CD57-PD1- CD8 T cells at 12-month transplant (p < .05 for all).

CONCLUSIONS

Children with obesity have distinct immunophenotypes that may influence the tailoring of immunosuppression.

Epidemiology of pediatric chronic kidney disease/kidney failure: learning from registries and cohort studies

Although the concept of chronic kidney disease (CKD) in children is similar to that in adults, pediatric CKD has some peculiarities, and there is less evidence and many factors that are not clearly understood. The past decade has witnessed several additional registry and cohort studies of pediatric CKD and kidney failure. The most common underlying disease in pediatric CKD and kidney failure is congenital anomalies of the kidney and urinary tract (CAKUT), which is one of the major characteristics of CKD in children. The incidence/prevalence of CKD in children varies worldwide. Hypertension and proteinuria are independent risk factors for CKD progression; other factors that may affect CKD progression are primary disease, age, sex, racial/genetic factors, urological problems, low birth weight, and social background. Many studies based on registry data revealed that the risk factors for mortality among children with kidney failure who are receiving kidney replacement therapy are younger age, female sex, non-White race, non-CAKUT etiologies, anemia, hypoalbuminemia, and high estimated glomerular filtration rate at dialysis initiation. The evidence has contributed to clinical practice. The results of these registry-based studies are expected to lead to new improvements in pediatric CKD care.

Effect of pre and post-transplant body mass index on pediatric kidney transplant outcomes

Introduction

Kidney transplantation (KT) has been established as an efficient treatment of end stage renal disease (ESRD) with the advantage of allowing the patient to live a nearly healthy life. We aimed to determine whether pre-transplant body mass index (BMI) affects renal allograft function and survival in pediatric KT recipients.

Methods

cross sectional cohort study included 50 post KT recipients (more than 3 years) with an age range of 10 to 15 years, regularly following at the Kidney Transplantation Outpatient Clinic, Cairo University Children’s Hospital, were subjected to a detailed history and physical examination, laboratory investigation in the form of fasting blood glucose (FBG),oral glucose tolerance test (OGTT), lipid profile, hemoglobin A1c (HbA1c) and microalbuminuria.

Results

Pre- post- kidney transplant BMI has significant positive correlation with graft rejection episodes, HbA1c, FBG, BMI post-KT, total cholesterol, triglycerides, and low-density lipoprotein (p < 0.01). There was a statistically significant negative correlation between the mean difference of BMI (post – pre) and graft survival in years (p = 0.036). Obese patients displayed lower survival compared with non-obese subjects at 5 years, but this was statistically not significant (p-value = 0.165).

Conclusion

obesity is an independent risk factor for graft loss and patient death in kidney transplantation. Careful patient selection with pre-transplantation weight reduction is mandatory to reduce the rate of early post-transplantation complications and to improve long-term outcomes.

Assessment and management of obesity and metabolic syndrome in children with CKD stages 2-5 on dialysis and after kidney transplantation-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

Obesity and metabolic syndrome (O&MS) due to the worldwide obesity epidemic affects children at all stages of chronic kidney disease (CKD) including dialysis and after kidney transplantation. The presence of O&MS in the pediatric CKD population may augment the already increased cardiovascular risk and contribute to the loss of kidney function. The Pediatric Renal Nutrition Taskforce (PRNT) is an international team of pediatric renal dietitians and pediatric nephrologists who develop clinical practice recommendations (CPRs) for the nutritional management of children with kidney diseases. We present CPRs for the assessment and management of O&MS in children with CKD stages 2-5, on dialysis and after kidney transplantation. We address the risk factors and diagnostic criteria for O&MS and discuss their management focusing on non-pharmacological treatment management, including diet, physical activity, and behavior modification in the context of age and CKD stage. The statements have been graded using the American Academy of Pediatrics grading matrix. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs based on the clinical judgment of the treating physician and dietitian. Research recommendations are provided. The CPRs will be periodically audited and updated by the PRNT.

Association of obesity with mortality and clinical outcomes in children and adolescents with transplantation: A systematic review and meta-analysis

Obesity might be associated with mortality and clinical outcomes following transplantation; however, the direction of this relationship has not been well-recognized in youth. The aim of this systematic review and meta-analysis was to investigate the association of obesity with post-transplant mortality and clinical outcomes in children and adolescents. Following a systematic search of observational studies published by December 2018 in PubMed, Scopus, Embase, and Cochrane library, 15 articles with total sample size of 50,498 patients were included in the meta-analysis. The main outcome was mortality and secondary outcomes included acute graft versus host disease (GVHD), acute rejection, and overall graft loss. The pooled data analyses showed significantly higher odds of long term mortality (OR 1.30, 95% CI 1.15-1.48, P < 0.001, I² = 50.3%), short term mortality (OR 1.79, 95% CI 1.19-2.70, P = 0.005, I² = 59.6%), and acute GVHD (OR 2.13, 95% CI 1.5-3.02, P < 0.001, I² = 1.7%) in children with obesity. There were no significant differences between patients with and without obesity in terms of acute rejection (OR 1.07, 95% CI 0.98-1.16, P = 0.132, I² = 7.5%) or overall graft loss (OR 1.04, 95% CI 0.84-1.28, P = 0.740, I² = 51.6%). This systematic review and meta-analysis has stated higher post-transplant risk of short and long term mortality and higher risk of acute GVHD in children with obesity compared to those without obesity. Future clinical trials are required to investigate the effect of pre-transplant weight management on post-transplant outcomes to provide insights into the clinical application of these findings. This may in turn lead to establish guidelines for the management of childhood obesity in transplantations.

Growth in children on kidney replacement therapy: a review of data from patient registries

Growth retardation is a major complication in children with chronic kidney disease (CKD) and on kidney replacement therapy (KRT). Conversely, better growth in childhood CKD is associated with an improvement in several hard morbidity-mortality endpoints. Data from pediatric international registries has demonstrated that improvements in the overall conservative management of CKD, the search for optimal dialysis, and advances in immunosuppression and kidney transplant techniques have led to a significant improvement of final height over time. Infancy still remains a critical period for adequate linear growth, and the loss of stature during the first years of life influences final height. Preliminary new original data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry confirm an association between the final height and the height attained at 2 years in children on KRT.

Longitudinal outcomes of body mass index in overweight and obese children with chronic kidney disease

BACKGROUND

Longitudinal changes in body mass index (BMI) among overweight and obese children with chronic kidney disease (CKD) are not well characterized. We studied longitudinal trajectories and correlates of these trajectories, as results may identify opportunities to optimize health outcomes.

METHODS

Longitudinal changes in age-sex-specific BMI z-scores over 1851 person-years of follow-up were assessed in 524 participants of the Chronic Kidney Disease in Children Study. A total of 353 participants were categorized as normal (BMI > 5th to < 85th percentile), 56 overweight (BMI ≥ 85th to 95th percentile) and 115 obese (BMI ≥ 95th percentile) based on the average of three BMI measurements during the first year of follow-up. Studied covariates included age, sex, race, CKD etiology, corticosteroid usage, household income, and maternal education.

RESULTS

In unadjusted analysis, BMI z-scores decreased over time in elevated BMI groups (overweight: mean = - 0.06 standard deviations (SD) per year, 95% CI: - 0.11, - 0.01; obese: mean = - 0.04 SD per year, 95% CI: - 0.07, - 0.01). Among obese children, only age was associated with change in BMI z-score; children < 6 years had a mean decrease of 0.19 SD during follow-up (95% CI: - 0.30, - 0.09). Socioeconomic factors were not associated with change in BMI.

CONCLUSION

Overweight and obese children with CKD demonstrated a significant annual decline in BMI, though the absolute change was modest. Among obese children, only age < 6 years was associated with significant decline in BMI. Persistence of elevated BMI in older children and adolescents with CKD underscores the need for early prevention and effective intervention.

Factors associated with long-term graft survival in pediatric kidney transplant recipients

Pediatric kidney transplant recipients generally have good outcomes post-transplantation. However, the younger age and longer life span after transplantation in the pediatric population make understanding the multifactorial nature of long-term graft survival critical. This investigation analyzes factors associated with 10-year survival to identify areas for improvement in patient care. Kaplan-Meier with log-rank test and univariable and multivariable logistic regression methods were used to retrospectively analyze 7785 kidney transplant recipients under the age of 18 years from January 1, 1998, until March 9, 2008, using United Network for Organ Sharing (UNOS) data. Our end-point was death-censored 10-year graft survival after excluding recipients whose grafts failed within one year of transplant. Recipients aged 5-18 years had lower 10-year graft survival, which worsened as age increased: 5-9 years (OR: 0.66; CI: 0.52-0.83), 10-14 years (OR: 0.43; CI: 0.33-0.55), and 15-18 years (OR: 0.34; CI: 0.26-0.44). Recipient African American ethnicity (OR: 0.67; CI: 0.58-0.78) and Hispanic donor ethnicity (OR: 0.82; CI: 0.72-0.94) had worse outcomes than other donor and recipient ethnicities, as did patients on dialysis at the time of transplant (OR: 0.82; CI: 0.73-0.91). Recipient private insurance status (OR: 1.35; CI: 1.22-1.50) was protective for 10-year graft survival. By establishing the role of age, race, and insurance status on long-term graft survival, we hope to guide clinicians in identifying patients at high risk for graft failure. This study highlights the need for increased allocation of resources and medical care to reduce the disparity in outcomes for certain patient populations.

Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia

Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.

Incidence and Risk Factors of Obesity in Childhood Solid-Organ Transplant Recipients

BACKGROUND

Obesity is a significant public health concern; however, the incidence post solid-organ transplantation is not well reported.

METHODS

This study determined the incidence and risk factors of obesity among pediatric solid-organ transplant recipients (heart, lung, liver, kidney, multiorgan) at The Hospital for Sick Children (2002-2011), excluding prevalent obesity. Follow-up occurred from transplantation until development of obesity, last follow-up, or end of study. Incidence of obesity was determined overall, by baseline body mass index, and organ group. Risk factors were assessed using Cox proportional-hazards regression.

RESULTS

Among 410 (55% male) children, median transplant age was 8.9 (interquartile range [IQR]: 1.0-14.5) years. Median follow-up time was 3.6 (IQR: 1.5-6.4) years. Incidence of obesity was 65.2 (95% confidence interval [CI]: 52.7-80.4) per 1000 person-years. Overweight recipients had a higher incidence, 190.4 (95% CI: 114.8-315.8) per 1000 person-years, than nonoverweight recipients, 56.1 (95% CI: 44.3-71.1). Cumulative incidence of obesity 5-years posttransplant was 24.1%. Kidney relative to heart recipients had the highest risk (3.13 adjusted hazard ratio [aHR]; 95% CI: 1.53-6.40) for obesity. Lung and liver recipients had similar rates to heart recipients. Those with higher baseline body mass index (z-score; 1.72 aHR; 95% CI: 1.39-2.14), overweight status (2.63 HR; 95% CI: 1.71-4.04), and younger transplant age (y; 1.18 aHR; 95% CI: 1.12-1.25) were at highest risk of obesity. Higher cumulative steroid dosage (per 10 mg/kg) was associated with increased risk of obesity after adjustment.

CONCLUSIONS

Among all transplanted children at The Hospital for Sick Children, 25% developed obesity within 5-years posttransplant. Kidney recipients, younger children, those overweight at transplant, and those with higher cumulative steroid use (per 10 mg/kg) were at greatest risk. Early screening and intervention for obesity are important preventative strategies.

Metabolic Disorders with Kidney Transplant

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

Can childhood obesity influence later chronic kidney disease?

Childhood overweight and obesity affects more and more children. Whilst associations of childhood overweight with later outcomes such as hypertension, diabetes and cardiovascular disease have been well documented, less is known about the association of childhood overweight and obesity with kidney disease. We review the existing evidence for the association of childhood obesity with markers of childhood and adult kidney disease. Whilst there is some evidence for an association, studies have not been able to distinguish between childhood being a sensitive time to develop later kidney problems, or whether observed associations of childhood obesity with poor outcomes are driven by greater lifelong exposure to obesity.

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.

Non-immunologic allograft loss in pediatric kidney transplant recipients

Non-immunologic risk factors are a major obstacle to realizing long-term improvements in kidney allograft survival. A standardized approach to assess donor quality has recently been introduced with the new kidney allocation system in the USA. Delayed graft function and surgical complications are important risk factors for both short- and long-term graft loss. Disease recurrence in the allograft remains a major cause of graft loss in those who fail to respond to therapy. Complications of over immunosuppression including opportunistic infections and malignancy continue to limit graft survival. Alternative immunosuppression strategies are under investigation to limit calcineurin inhibitor toxicity. Finally, recent studies have confirmed long-standing observations of the significant negative impact of a high-risk age window in late adolescence and young adulthood on long-term allograft survival.

Outcomes of underweight, overweight, and obese pediatric kidney transplant recipients

BACKGROUND

Obesity is a risk factor for poor transplant outcomes in the adult population. The effect of pre-transplant weight on pediatric kidney transplantation is conflicting in the existing literature.

METHODS

Data was collected from the Organ Procurement and Transplantation Network (OPTN) database on recipients aged 2-21 years who received a kidney-only transplant from 1987 to 2017. Recipients were categorized into underweight, normal, overweight, and obese cohorts. Using adjusted regression models, the relationship between recipient weight and various graft outcomes (delayed graft function [DGF], acute rejection, prolonged hospitalization, graft failure, mortality) was examined.

RESULTS

18,261 transplant recipients (mean age 14.1 ± 5.5 years) were included, of which 8.7% were underweight, 14.8% were overweight, and 15% were obese. Obesity was associated with greater odds of DGF (OR 1.3 95% CI 1.13-1.49, p < 0.001), acute rejection (OR 1.23 95% CI 1.06-1.43, p < 0.01), and prolonged hospitalization (OR 1.35 95% CI 1.17-1.54, p < 0.001) as well as greater hazard of graft failure (HR 1.13 95% CI 1.05-1.22, p = 0.001) and mortality (HR 1.19 95% CI 1.05-1.35, p < 0.01). The overweight cohort had an increased risk of graft failure (HR 1.08 95% CI 1.001-1.16, p = 0.048) and increased odds of DGF (OR 1.2 95% CI 1.04-1.38, p = 0.01) and acute rejection (OR 1.18 95% CI 1.01-1.38, p = 0.04). When stratified by age group, the increased risk was realized among younger and older age groups for obese and overweight. Underweight had lower risk of 1-year graft failure (HR 0.82 95% CI 0.71-0.94, p < 0.01), overall graft failure in the 13-17-yr. age group (HR 0.84 95% CI 0.72-0.99, p = 0.03) and acute rejection in the 2-5-yr. age group (OR 0.24 95% CI 0.09-0.66, p < 0.01).

CONCLUSION

Pre-transplant weight status and age impact pediatric kidney transplant outcomes. Recipient underweight status seems to be protective against adverse outcomes while overweight and obesity may lead to poorer graft and patient outcomes.

Effect of BMI on allograft function and survival in pediatric renal transplant recipients

OBJECTIVE

To determine whether pre-transplant body mass index (BMI) affects renal allograft function and survival in pediatric renal transplant recipients.

STUDY DESIGN

This is a retrospective cohort study using the Organ Procurement and Transplantation Network data from 2000 to 2013 to compare time to total allograft loss (allograft failure or death), prevalence of delayed graft function, prevalence of acute rejection, and estimated glomerular filtration rate (eGFR) post-transplant in pediatric renal transplant recipients categorized by BMI z-score.

RESULTS

A total of 8804 kidney transplant recipients met our inclusion criteria, and of those, 6% were underweight, 14% were overweight, and 17% were obese pre-transplant. The adjusted hazard ratio (HR) for allograft failure was significantly higher for obese recipients compared to normal weight recipients (HR 1.25, 95% CI 1.1, 1.42); for every 1 point increase in BMI z-score, there was a 7% increased hazard of allograft failure (HR 1.07; 95% CI 1.03-1.1, p < 0.001). The prevalence of delayed graft function and acute rejection increased with higher BMI z-score category; however, this difference did not reach statistical significance. eGFR at 1 and 5 years post-transplant decreased with higher BMI z-score although it was only statistically significant at 1 year.

CONCLUSIONS

Obesity is prevalent in pediatric renal transplant recipients, and obese, but not overweight or underweight, pediatric renal transplant recipients have an increased risk of allograft failure. Implementation of effective obesity interventions in pediatric renal transplant recipients is of critical importance to improve longevity of the renal allograft.

Renal Metabolic Programming Is Linked to the Dynamic Regulation of a Leptin-Klf15 Axis and Akt/AMPKα Signaling in Male Offspring of Obese Dams

Childhood obesity is associated with renal diseases. Maternal obesity is a risk factor linked to increased adipocytokines and metabolic disorders in the offspring. Therefore, we studied the impact of maternal obesity on renal-intrinsic insulin and adipocytokine signaling and on renal function and structure. To induce maternal obesity, female mice were fed a high-fat diet (HFD) or a standard diet (SD; control group) prior to mating, during gestation, and throughout lactation. A third group of dams was fed HFD only during lactation (HFD-Lac). After weaning at postnatal day (P)21, offspring of all groups received SD. Clinically, HFD offspring were overweight and insulin resistant at P21. Although no metabolic changes were detected at P70, renal sodium excretion was reduced by 40%, and renal matrix deposition increased in the HFD group. Mechanistically, two stages were differentiated. In the early stage (P21), compared with the control group, HFD showed threefold increased white adipose tissue, impaired glucose tolerance, hyperleptinemia, and hyperinsulinemia. Renal leptin/Stat3-signaling was activated. In contrast, the Akt/ AMPKα cascade and Krüppel-like factor 15 expression were decreased. In the late stage (P70), although no metabolic differences were detected in HFD when compared with the control group, leptin/Stat3-signaling was reduced, and Akt/AMPKα was activated in the kidneys. This effect was linked to an increase of proliferative (cyclinD1/D2) and profibrotic (ctgf/collagen IIIα1) markers, similar to leptin-deficient mice. HFD-Lac mice exhibited metabolic changes at P21 similar to HFD, but no other persistent changes. This study shows a link between maternal obesity and metabolic programming of renal structure and function and intrinsic-renal Stat3/Akt/AMPKα signaling in the offspring.

Body mass index as a predictor of outcomes among pediatric kidney transplant recipient

Controversies exist regarding the impact of obesity on patients undergoing kidney transplantation. We sought to estimate the association between BMI and patient outcomes (survival and graft function) among pediatric kidney transplant patients in the USA. We conducted a retrospective analysis of the United Network for Organ Sharing database (1987-2013), which revealed 13 014 pediatric patients (<18 years old) who underwent primary kidney transplantation. Patients were stratified into five BMI categories established by the World Health Organizations according to their Z score, which is based on age, gender and BMI. The -2, 0, and +2 categories were collapsed and served as the reference group, while the -3 (thin) and +3 (obese) categories were evaluated for differences in graft and patient survival. The survival rates between these categories were compared using the Kaplan-Meier estimator. Cox proportional hazards models were constructed to adjust for recipient and donor characteristics to estimate the risk of graft loss and mortality associated with BMI. Logistic regression models were estimated to evaluate whether there was an association between BMI and DGF. There were no differences in overall patient (P=.1655) or graft (P=.1688) survival between the severely thin, normal, and obese patients. Adjusted models also revealed no statistically significant differences in graft or patient survival. There were no differences in the odds of DGF (both unadjusted and adjusted) among the three groups. The prevalence of obesity is increasing among children who present for kidney transplant in the USA. In this national study of pediatric kidney transplant recipients, there was no difference in graft or patient survival and no differences in rates of DGF among obese children compared to normal and underweight children undergoing kidney transplantation.

Cardiometabolic risks vary by weight status in pediatric kidney and liver transplant recipients: A cross-sectional, single-center study in the USA

There is an increasing need to understand long-term metabolic changes and resultant comorbidities because life expectancy is increasing after pediatric kidney and liver transplants. We evaluated differences in classic and novel cardiometabolic biomarkers among obese and normal weight adolescent transplant recipients. We enrolled a total of 80 adolescent (mean±SD, 14.8 years ±3.0) transplant recipients (63 kidney, 17 liver) with mean duration from transplantation of 6.0 (±4.1) years. Among kidney transplant recipients, overweight and obese individuals had higher leptin (16.7 vs 7.5 μg/mL, P<.001), lower HDL (1.1 vs 1.3 mmol/L, P=.02), higher free fatty acid (0.6 vs 0.5 mmol/L, P=.03), higher apoB-to-apoA1 ratio (0.8 vs 0.6, P=.03), and higher glucose (5.8 vs 4.3 mmol/L, P=.03) concentrations compared to normal weight individuals. Regardless of obesity status, over half of all participants (57.5%) were considered at high cardiometabolic risk using consensus guidelines, and this was more pronounced for kidney transplant recipients (61.9%). Post-transplantation adolescents have increased cardiometabolic risk characterized by traditional risk factors of obesity and diabetes. The presence of obesity significantly worsens biomarkers of cardiometabolic risk. Future studies should explore whether treatment of obesity can improve the health and long-term outcomes for children undergoing solid organ transplant.

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.

Hypertension in the Pediatric Kidney Transplant Recipient

Hypertension after kidney transplant is a frequent occurrence in pediatric patients. It is a risk factor for graft loss and contributes to the significant burden of cardiovascular disease (CVD) in this population. The etiology of posttransplant hypertension is multifactorial including donor factors, recipient factors, medications, and lifestyle factors similar to those prevalent in the general population. Ambulatory blood pressure monitoring has emerged as the most reliable method for measuring hypertension in pediatric transplant recipients, and many consider it to be essential in the care of these patients. Recent technological advances including measurement of carotid intima-media thickness, pulse wave velocity, and myocardial strain using specked echocardiography and cardiac magnetic resonance imaging have improved our ability to assess CVD burden. Since hypertension remains underrecognized and inadequately treated, an early diagnosis and an appropriate control should be the focus of therapy to help improve patient and graft survival.

Consequences of Recipient Obesity on Postoperative Outcomes in a Renal Transplant: A Systematic Review and Meta-Analysis

OBJECTIVES

The prevalence of obesity is increasing rapidly and globally, yet systemic reviews on this topic are scarce. Our meta-analysis and systemic review aimed to assess how obesity affects 5 postoperative outcomes: biopsy-proven acute rejection, patient death, allograft loss, type 2 diabetes mellitus after transplant, and delayed graft function.

MATERIALS AND METHODS

We evaluated peer-reviewed literature from 22 medical databases. Studies were included if they were conducted in accordance with the Meta-analysis of Observational Studies in Epidemiology criteria, only examined postoperative outcomes in adult patients, only examined the relation between recipient obesity at time of transplant and our 5 postoperative outcomes, and had a minimum score of > 5 stars on the Newcastle-Ottawa scale for nonrandomized studies. Reliable conclusions were ensured by having our studies examined against 2 internationally known scoring systems. Obesity was defined in accordance with the World Health Organization as having a body mass index of > 30 kg/m(2). All obese recipients were compared versus "healthy" recipients (body mass index of 18.5-24.9 kg/m(2)). Hazard ratios were calculated for biopsy-proven acute rejection, patient death, allograft loss, and type 2 diabetes mellitus after transplant. An odds ratio was calculated for delayed graft function.

RESULTS

We assessed 21 retrospective observational studies in our meta-analysis (N = 241 381 patients). In obese transplant recipients, hazard ratios were 1.51 (95% confidence interval, 1.24-1.78) for presence of biopsy-proven acute rejection, 1.19 (95% confidence interval, 1.10-1.31) for patient death, 1.54 (95% confidence interval, 1.38-1.68) for allograft loss, and 1.01 (95% confidence interval, 0.98-1.07) for development of type 2 diabetes mellitus. The odds ratio for delayed graft function was 1.81 (95% confidence interval, 1.51-2.13).

CONCLUSIONS

Our meta-analysis clearly demonstrated greater risks for obese renal transplant recipients and poorer postoperative outcomes with obesity. We confidently recommend renal transplant candidates seek medically supervised weight loss before transplant.

Renal transplantation in Bardet-Biedl Syndrome

BACKGROUND

Renal anomalies are common in patients with Bardet-Biedl syndrome (BBS), a renal cystic ciliopathy with multi-systemic features. Renal transplantation is indicated in cases of end-stage renal disease (ESRD), but transplant centers may be hesitant to perform the necessary transplant in light of the multitude of metabolic comorbidities these patients often face with the potential to complicate outcomes.

METHODS

Data from the Clinical Registry Investigating BBS (CRIBBS) were used to investigate renal transplant outcomes in the largest BBS cohort described to date.

RESULTS

Of the 206 patients enrolled in the CRIBBS, 21 children (10.2 %; 16 girls, 5 boys; median age 8.4 years) had been diagnosed with ESRD. Renal transplantation was performed in 18 of these individuals between 1982 and 2015, including repeat transplantation in some cases, for a total of 22 kidneys. Overall graft survival was 81.6 % at 1 year post-transplantation, 75.7 % at 5 years, 59 % at 10 years, and 49.2 % at 25 years. Patient survival was 94.4 % at 1 year post-transplantation, 87.2 % at 8 years, and 79.3 % at 25 years.

CONCLUSIONS

At a median follow-up time of 97 months, relatively few complications of renal transplantation were reported in the patients of this study. However, body mass index was significantly elevated in transplanted individuals compared to non-transplanted individuals participating in CRIBBS at the most recent follow-up. Although the frequency of obesity and other manifestations of the metabolic syndrome warrant meticulous management in this high-risk population, favorable long-term outcomes suggest that renal transplantation is a viable option for patients with BBS and ESRD.

Pre-transplant dialysis modality does not influence short- or long-term outcome in kidney transplant recipients: analysis of paired kidneys from the same deceased donor

Previous studies have reported contradictory results regarding the effect of pre-transplant dialysis modality on the outcomes after kidney transplantation (KT). To minimize the confounding effect of donor-related variables, we performed a donor-matched retrospective comparison of 160 patients that received only one modality of pre-transplant dialysis (peritoneal dialysis [PD] and hemodialysis [HD] in 80 patients each) and that subsequently underwent KT at our center between January 1990 and December 2007. Cox regression models were used to evaluate the association between pre-transplant dialysis modality and primary study outcomes (death-censored graft survival and patient survival). To control for imbalances in recipient-related baseline characteristics, we performed additional adjustments for the propensity score (PS) for receiving pre-transplant PD (versus HD). There were no significant differences according to pre-transplant dialysis modality in death-censored graft survival (PS-adjusted hazard ratio [aHR]: 0.65; 95% confidence interval [95% CI]: 0.25-1.68) or patient survival (aHR: 0.58; 95% CI: 0.13-2.68). There were no differences in 10-year graft function or in the incidence of post-transplant complications either, except for a higher risk of lymphocele in patients undergoing PD (odds ratio: 4.31; 95% CI: 1.15-16.21). In conclusion, pre-transplant dialysis modality in KT recipients does not impact short- or long-term graft outcomes or patient survival.

Metabolic consequences of modern immunosuppressive agents in solid organ transplantation

Among other factors, sophistication of immunosuppressive (IS) regimen accounts for the remarkable success attained in the short- and medium-term solid organ transplant (SOT) survival. The use of steroids, mycophenolate mofetil and calcineurin inhibitors (CNI) have led to annual renal graft survival rates exceeding 90% in the last six decades. On the other hand, attrition rates of the allograft beyond the first year have remained unchanged. In addition, there is a persistent high cardiovascular (CV) mortality rate among transplant recipients with functioning grafts. These shortcomings are in part due to the metabolic effects of steroids, CNI and sirolimus (SRL), all of which are implicated in hypertension, new onset diabetes after transplant (NODAT), and dyslipidemia. In a bid to reduce the required amount of harmful maintenance agents, T-cell-depleting antibodies are increasingly used for induction therapy. The downsides to their use are greater incidence of opportunistic viral infections and malignancy. On the other hand, inadequate immunosuppression causes recurrent rejection episodes and therefore early-onset chronic allograft dysfunction. In addition to the adverse metabolic effects of the steroid rescue needed in these settings, the generated proinflammatory milieu may promote accelerated atherosclerotic disorders, thus setting up a vicious cycle. The recent availability of newer agent, belatacept holds a promise in reducing the incidence of metabolic disorders and hopefully its long-term CV consequences. Although therapeutic drug monitoring as applied to CNI may be helpful, pharmacodynamic tools are needed to promote a customized selection of IS agents that offer the most benefit to an individual without jeopardizing the allograft survival.

Inflammation and nutrition in children with chronic kidney disease

Chronic inflammation and nutritional imbalance are important comorbid conditions that correlate with poor clinical outcomes in children with chronic kidney disease (CKD). Nutritional disorders such as cachexia/protein energy wasting, obesity and growth retardation negatively impact the quality of life and disease progression in children with CKD. Inadequate nutrition has been associated with growth disturbances in children with CKD. On the other hand, over-nutrition and obesity are associated with poor outcomes in children with CKD. The exact mechanisms leading to these unfavorable conditions are not fully elucidated and are most likely multifactorial. In this review, we focus on the pathophysiology of nutrition disorders and inflammation and their impact on clinical outcomes in children with CKD.

Height at First RRT and Mortality in Children

BACKGROUND AND OBJECTIVES

Poor linear growth is common in children with CKD and has been associated with higher mortality. However, recent data in adult dialysis patients have suggested a higher risk of death in persons of tall stature. In this study, we aimed to examine the risk of all-cause and cause-specific mortality in children at both extremes of height at the time of first RRT.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the US Renal Data System, we performed a retrospective analysis of 13,218 children aged 2-19 years, who received their first RRT (dialysis or transplant) during 1995-2011. We used adjusted Cox models to examine the association between short (<3rd percentile) and tall (>3rd percentile) stature and risk of death, compared with less extreme heights.

RESULTS

Over a median follow-up of 7.1 years, there were 1721 deaths. Risk of death was higher in children with short (hazard ratio, 1.49; 95% confidence interval, 1.33 to 1.66) and tall stature (hazard ratio, 1.32; 95% confidence interval, 1.03 to 1.69) in adjusted analysis. In secondary analyses, there was a statistically significant interaction between height and body mass index categories (P=0.04), such that the association of tall stature with higher mortality was limited to children with elevated body mass index (defined as ≥95th percentile for age and sex). Children with short stature had a higher risk of cardiac- and infection-related death, whereas children with tall stature had a higher risk of cancer-related death.

CONCLUSIONS

Children with short and tall stature are at higher mortality risk, although this association was modified by body mass index at time of first RRT. Studies to further explore the reasons behind the higher risk of mortality in children with extremes of height at the time of first RRT are warranted.

Paediatric obesity and renal transplantation: current challenges and solutions

The increased incidence of obesity in the paediatric population poses significant challenges to renal transplantation. Whilst the body mass index appears to be widely used as a measure of obesity in adults, there are no standardised definitions in the paediatric population, making comparative analyses difficult. In the paediatric transplant population, obesity is associated with an increased incidence of surgical complications, diabetes, hyperlipidaemia and cardiovascular morbidity, leading to diminished graft function and impacting patient and graft survival. Management of obesity in renal transplantation requires multiple interventions starting with life-style and behavioural modification combined with medical and possibly surgical therapies, representing a unique challenge in the childhood setting. In this review we discuss the current challenges of obesity and potential solutions in the setting of paediatric transplantation.

Improved cardiovascular risk factors in pediatric renal transplant recipients on steroid avoidance immunosuppression: A study of the Midwest Pediatric Nephrology Consortium

Several centers have examined the implementation of immunosuppression protocols that minimize steroid exposure. This study retrospectively examined cardiovascular risk factors in 70 pediatric renal transplant recipients on steroid avoidance-based immunosuppression over three yr compared to matched pediatric patients maintained on chronic corticosteroids. Although higher rates of acute rejection were noted in the steroid-avoidant group (22% vs. 16%, p = 0.034), graft function was similar (67 + 10 mL/min/1.73 m(2) vs. 72 + 12 mL/min/1.73 m(2)) (p = 0.053). The steroid-avoidant group demonstrated improved growth (height z-score -0.41 + 5.9 vs. -1.1 + 0.041) with a decrease in the prevalence of obesity (24% vs. 34%, p = 0.021). Indexed systolic blood pressures were lower beginning at six months post-transplant in the steroid-avoidant group (1.21 + 0.15 vs. 1.51 + 0.22, p = 0.020). Indexed diastolic blood pressures were lower beginning at 12 months post-transplant (0.91 + 0.11 vs. 1.12 + 0.18, p = 0.037). Differences in total serum cholesterol values and serum glucose values were not statistically significant. Beginning at 12 months, a statistically significant decrease in left ventricular mass index (39.2 + 11.3 vs. 49.4 + 14.5, p = 0.014) was noted in patients on steroid-avoidant immunosuppression, which corresponded to a significant decrease in the prevalence of left ventricular hypertrophy in these patients by two yr post-transplant (35% vs. 48%, p = 0.012). Systolic blood pressure and BMI were independent predictors of left ventricular hypertrophy.

Association of Body Mass Index with Patient-Centered Outcomes in Children with ESRD

Obesity is associated with less access to transplantation among adults with ESRD. To examine the association between body mass index at ESRD onset and survival and transplantation in children, we performed a retrospective analysis of children ages 2-19 years old beginning RRT from 1995 to 2011 using the US Renal Data System. Among 13,172 children, prevalence of obesity increased from 14% to 18%, whereas prevalence of underweight decreased from 12% to 9% during this period. Over a median follow-up of 7.0 years, 10,004 children had at least one kidney transplant, and 1675 deaths occurred. Risk of death was higher in obese (hazard ratio [HR], 1.17; 95% confidence interval [95% CI], 1.03 to 1.32) and underweight (HR, 1.26; 95% CI, 1.09 to 1.47) children than children with normal body mass indices. Obese and underweight children were less likely to receive a kidney transplant (HR, 0.92; 95% CI, 0.87 to 0.97; HR, 0.83; 95% CI, 0.78 to 0.89, respectively). Obese children had lower odds of receiving a living donor transplant (odds ratio, 0.85; 95% CI, 0.74 to 0.98) if the transplant occurred within 18 months of ESRD onset. Adjustment for transplant in a time-dependent Cox model attenuated the higher risk of death in obese but not underweight children (HR, 1.09; 95% CI, 0.96 to 1.24). Lower rates of kidney transplantation may, therefore, mediate the higher risk of death in obese children with ESRD. The increasing prevalence of obesity among children starting RRT may impede kidney transplantation, especially from living donors.

New-onset diabetes after kidney transplant in children

The development of new-onset diabetes after kidney transplantation (NODAT) is associated with reduced graft function, increased cardiovascular morbidity and lower patient survival among adult recipients. In the pediatric population, however, the few studies examining NODAT have yielded inconsistent results. Therefore, the true incidence of NODAT in the pediatric population has been difficult to establish. The identification of children and adolescents at risk for NODAT requires appropriate screening questions and tests pre- and post-kidney transplant. Several risk factors have been implicated in the pathogenesis of NODAT and post-transplant glucose intolerance, including African American race, obesity, family history of diabetes and the type of immunosuppressant regimen. Moreover, uremia per se results in a state of insulin resistance that increases the risk of developing diabetes post-transplant. When an individual becomes glucose intolerant, early lifestyle modification and antihyperglycemic measures with tailoring of the immunosuppressant regimen should be implemented to prevent the development of NODAT. For the child or adolescent with NODAT, antihyperglycemic therapy should be prescribed in order to achieve optimal glycemic control, ultimately reducing complications and improving overall allograft and patient survival. In this article, we review the risk factors, screening methods, diagnosis, management and outcome of children and adolescents with NODAT and post-kidney transplant glucose intolerance.

Body mass index and mortality in kidney transplant recipients: a systematic review and meta-analysis

BACKGROUND

A higher body mass index (BMI) seems to be linked to survival advantage in maintenance hemodialysis patients. However, it is uncertain if this 'obesity survival paradox' is also observed in kidney transplant recipients. Hence, we systematically reviewed the literature on the impact of pre-transplantation BMI on all-cause mortality in this population.

METHODS

We searched MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane CENTRAL for relevant studies up to July 2013. Two investigators independently selected the studies using predefined criteria, abstracted the data from the included studies, and independently assessed each study's quality using the Newcastle-Ottawa Quality Assessment Scale. In addition to the qualitative synthesis, we quantitatively pooled the results of the studies with clinical, methodological, and statistical homogeneity.

RESULTS

We screened 7,123 records, from which we included 11 studies (with a total of 305,392 participants) in this systematic review and 4 studies in the meta-analyses. In the only study that included children, obesity was linked to higher mortality in children of 6-12 years old. For adults, our meta-analyses indicated that compared to normal BMI, underweight [Hazard Ratio (HR): 1.09; 95% Confidence Interval (CI): 1.02-1.20], overweight (HR: 1.07; 95% CI: 1.04-1.12), and obese (HR: 1.20; 95% CI: 1.14-1.23) levels of BMI were associated with higher mortality.

CONCLUSION

The presence of the obesity survival paradox is unlikely in kidney transplant recipients since both extremes of pre-transplantation BMI are linked to higher mortality in this population.

Pediatric obesity and safety in inpatient settings: a systematic literature review

OBJECTIVE

Pediatric obesity affects more than 16% of American children and is associated with worse outcomes in hospitalized patients. A systematic literature review was performed to identify studies of adverse care events affecting obese pediatric patients in the emergency room, operating room, or inpatient wards.

EVIDENCE REVIEW

We systematically searched Medline for articles published from 1970 to 2013 regarding obesity and patient safety events in pediatric acute care settings. We determined the study design, number of patients studied, definition and prevalence of obesity, the relevant acute care setting, the specific association with obesity addressed, and the results of each study.

RESULTS AND CONCLUSION

Thirty-four studies documented both procedural complications and issues with general hospital care. Most were retrospective and focused on surgery or anesthesia. Obese patients may have increased risk for a variety of adverse events. Further study could improve institutional patient safety guidelines to enhance care for obese children.

Metabolic risk factors and long-term graft function after paediatric renal transplantation

The aim of this study was to evaluate metabolic risk factors and their impact on long-term allograft function in paediatric renal transplant (RTx) patients. We reviewed the medical records of 210 RTx patients who underwent transplantation at a median age of 4.5 years (range 0.7-18.2) and a median follow-up of 7.0 years (range 1.5-18.0). Data on lipid and glucose metabolism, uric acid levels, weight and blood pressure were collected up to 13 years post-RTx, and the findings were correlated with the measured glomerular filtration rate (GFR). Beyond the first year, GFR showed gradual deterioration with a mean decline of 2.4 ml/min/1.73 m(2)/year. Metabolic syndrome, overweight, hypertension and type 2 diabetes were diagnosed in 14-19%, 20-23%, 62-87% and 3-5% of the patients, respectively. These entities showed only mild association with the concomitant or long-term GFR values. Dyslipidaemia was common and hypertriglyceridaemia associated with a lower GFR at 1.5 and 5 years post-RTx (P = 0.008 and P = 0.017, respectively). Similarly, hyperuricaemia was frequent and associated significantly with GFR (P < 0.001). Except for hyperuricaemia and hypertriglyceridaemia, metabolic risk factors beyond the first postoperative year associated modestly with the long-term kidney graft function in paediatric RTx patients.

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

Is obesity a risk factor for chronic kidney disease in children?

There is a rapid increase worldwide in the prevalence of obesity in adults and children. Obesity is not only a comorbidity for chronic kidney disease (CKD) but may also be a risk factor for CKD. Epidemiological correlations and pathophysiological changes have been observed associating obesity with CKD. Low birth weight may be associated with both obesity and low nephron mass, leading to CKD later in life. Elevated levels of adipokines, such as leptin and adiponectin, in obesity may be factors in CKD pathogenesis and progression. Furthermore, various other factors, such as hypertension, increased cardiovascular morbidity, insulin resistance, dyslipidemia, and lipotoxicity, may play significant roles in the pathogenesis of CKD in obesity. Reduction in obesity, which is a potentially modifiable risk factor, might help decrease the burden of CKD in the population. Apart from individualized options, community-based interventions have the potential to create a strong impact in this condition.

Underweight, overweight and obesity in paediatric dialysis and renal transplant patients

BACKGROUND

The prevalence of childhood overweight is rising worldwide, but in children on renal replacement therapy (RRT) a poor nutritional status is still the primary concern. We aimed to study the prevalence of, and factors associated with, underweight and overweight/obesity in the European paediatric RRT population. Moreover, we assessed the evolution of body mass index (BMI) after the start of RRT.

METHODS

We included 4474 patients younger than 16 years from 25 countries of whom BMI data, obtained between 1995 and 2010, were available within the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry. Prevalence estimates for under- and overweight/obesity were calculated using age and sex-specific criteria of the World Health Organization (WHO, 0-1 year olds) and the International Obesity Task Force cut-offs (2-15 year olds).

RESULTS

The prevalence of underweight was 3.5%, whereas 20.8% of the patients were overweight and 12.5% obese. Factors associated with being underweight were receiving dialysis treatment and infant age. Among transplanted recipients, a very short stature (OR: 1.64, 95% CI: 1.40-1.92) and glucocorticoid treatment (OR: 1.23, 95% CI: 1.03-1.47) were associated with a higher risk of being overweight/obese. BMI increased post-transplant, and a lower BMI and a higher age at the start of RRT were associated with greater BMI changes during RRT treatment.

CONCLUSIONS

Overweight and obesity, rather than underweight, are highly prevalent in European children on RRT. Short stature among graft recipients had a strong association with overweight, while underweight appears to be only a problem in infants. Our findings suggest that nutritional management in children receiving RRT should focus as much on the prevention and treatment of overweight as on preventing malnutrition.

Influence of obesity on clinical outcomes in hospitalized children: a systematic review

IMPORTANCE

Obesity is prevalent among hospitalized children. Knowledge of the relationship between obesity and outcomes in hospitalized children will enhance nutrition assessment and provide opportunities for interventions.

OBJECTIVE

To systematically review the existing literature concerning the impact of obesity on clinical outcomes in hospitalized children.

EVIDENCE ACQUISITION

PubMed, Web of Science, and EMBASE databases were searched for studies of hospitalized children aged 2 to 18 years with identified obesity and at least 1 of the following clinical outcomes: all-cause mortality, incidence of infections, and length of hospital stay. Cohort and case-control studies were included. Cross-sectional studies, studies of healthy children, and those without defined criteria for classifying weight status were excluded. The Newcastle-Ottawa Scale was used to assess study quality.

RESULTS

Twenty-eight studies (26 retrospective; 24 cohort and 4 case-control) were included. Of the 21 studies that included mortality as an outcome, 10 reported a significant positive relationship between obesity and mortality. The incidence of infections was assessed in 8 of the 28 studies; 2 reported significantly more infections in obese compared with nonobese patients. Of the 11 studies that examined length of stay, 5 reported significantly longer lengths of hospital stay for obese children. Fifteen studies (53%) had a high quality score. Larger studies observed significant relationships between obesity and outcomes. Studies of critically ill, oncologic or stem cell transplant, and solid organ transplant patients showed a relationship between obesity and mortality.

CONCLUSIONS AND RELEVANCE

The available literature on the relationship between obesity and clinical outcomes is limited by subject heterogeneity, variations in criteria for defining obesity, and outcomes examined. Childhood obesity may be a risk factor for higher mortality in hospitalized children with critical illness, oncologic diagnoses, or transplants. Further examination of the relationship between obesity and clinical outcomes in this subgroup of hospitalized children is needed.