Posttransplant metabolic syndrome in children and adolescents after liver transplantation: a systematic review.

During long-term follow-up, 18% to 67% of pediatric liver transplant recipients are overweight or obese, with rates varying by age and pretransplant weight status. A similar prevalence of posttransplant obesity has been seen in adults. Adults also develop posttransplant metabolic syndrome and, consequently, cardiovascular disease at rates that exceed the rates in age- and sex-matched populations. Posttransplant metabolic syndrome has never been studied in pediatric liver transplant recipients, and this population is growing as transplant outcomes continue to improve. Here we systematically review the literature for each component of metabolic syndrome-obesity, hypertension, dyslipidemia, and glucose intolerance-in pediatric liver transplant recipients. Their rates of obesity are similar to the rates in children in the general U.S. population. However, hypertension, dyslipidemia, and diabetes are more common than would be expected in transplant recipients according to age, sex, and obesity severity. Immunosuppressive medications are major contributors. The limitations of previous studies, including heterogeneous methods of diagnosis, follow-up times, and immunosuppressive regimens, hinder the analysis of risk factors. Importantly, no studies have reported graft or patient outcomes associated with components of metabolic syndrome after pediatric liver transplantation. However, if the trends in children are similar to the trends seen in adults, these conditions may lead to significant long-term morbidity. Further research on the prevalence, causes, and consequences of posttransplant metabolic syndrome in pediatric liver transplant recipients is needed and will ultimately help to improve long-term outcomes.