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.