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

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.

Management of pediatric obesity as a pathway towards kidney transplantation

Obesity is an increasing problem in pediatrics, leading to cardiovascular, metabolic and psychosocial complications. Additionally, for patients with chronic kidney disease (CKD), obesity can lead to CKD progression towards end-stage renal disease (ESRD) needing renal-replacement therapy (RRT). It is well-established that the optimal type of RRT for children with ESRD is kidney transplantation, as it provides significantly better life expectancy and quality of life. Unfortunately, pediatric patients with CKD/ESRD and obesity face barriers getting to kidney transplantation and often remain on dialysis for a long time, which negatively impacts their life expectancy and quality of life. One barrier to kidney transplant is that Body Mass Index (BMI) is still considered by most transplant centers as the main criterion for obesity assessment, although more recent evidence suggests that BMI is not the best measure of adiposity. Clearcut evidence is lacking that obesity has a long-term negative impact upon the graft. Another barrier to transplant can be bias on the part of referring providers that can deter or delay referral to an obesity treatment program. Our article describes the barriers that pediatric obese patients with CKD and ESRD face in their way towards kidney transplantation. In addition, our article encourages pediatric nephrologists to early refer their patients with CKD and ESRD who suffer from obesity to a specialized obesity treatment program and/or bariatric surgery. Our article also describes the treatment options for pediatric patients with CKD and ESRD who suffer from obesity in order to make them eligible for a kidney transplant.

Childhood Obesity: Insight into Kidney Involvement

This review examines the impact of childhood obesity on the kidney from an epidemiological, pathogenetic, clinical, and pathological perspective, with the aim of providing pediatricians and nephrologists with the most current data on this topic. The prevalence of childhood obesity and chronic kidney disease (CKD) is steadily increasing worldwide, reaching epidemic proportions. While the impact of obesity in children with CKD is less pronounced than in adults, recent studies suggest a similar trend in the child population. This is likely due to the significant association between obesity and the two leading causes of end-stage renal disease (ESRD): diabetes mellitus (DM) and hypertension. Obesity is a complex, systemic disease that reflects interactions between environmental and genetic factors. A key mechanism of kidney damage is related to metabolic syndrome and insulin resistance. Therefore, we can speculate about an adipose tissue-kidney axis in which neurohormonal and immunological mechanisms exacerbate complications resulting from obesity. Adipose tissue, now recognized as an endocrine organ, secretes cytokines called adipokines that may induce adaptive or maladaptive responses in renal cells, leading to kidney fibrosis. The impact of obesity on kidney transplant-related outcomes for both donors and recipients is also significant, making stringent preventive measures critical in the pre- and post-transplant phases. The challenge lies in identifying renal involvement as early as possible, as it is often completely asymptomatic and not detectable through common markers of kidney function. Ongoing research into innovative technologies, such as proteomics and metabolomics, aims to identify new biomarkers and is constantly evolving. Many aspects of pediatric disease progression in the population of children with obesity still require clarification. However, the latest scientific evidence in the field of nephrology offers glimpses into various new perspectives, such as genetic factors, comorbidities, and novel biomarkers. Investigating these aspects early could potentially improve the prognosis of these young patients through new diagnostic and therapeutic strategies. Hence, the aim of this review is to provide a comprehensive exploration of the pathogenetic mechanisms and prevalent pathological patterns of kidney damage observed in children with obesity.