Prevalence of Obesity and Metabolic Changes After Kidney Transplantation: Hungarian Pediatric Cohort Study

Background. Cardiovascular mortality rate in patients with end-stage renal disease is 3 magnitudes higher than in the general population; it remains 10-fold higher after successful renal transplantation (Tx). Among others, obesity and hypertension can exert deleterious effects on vascular structure and function after Tx. Successful kidney transplantation may induce excessive weight gain in part because of the effects of steroid treatment. Methods. The purpose of this study was to evaluate the presence of obesity in Tx children, their obesity-related metabolic disturbances, and to assess their blood pressure and arterial stiffness in relation to obesity. Forty-one transplant children (age, 15.7 [3.5] years; 28 males) were studied. Body composition was assessed by body mass index (BMI), waist circumference, skin-fold measurements, and multifrequence bioimpedance analysis. Glucose metabolism, blood pressure, and arterial stiffness (with the use of pulse wave velocity) were studied. Age- and sex-dependent parameters were expressed as standard deviation scores (SDS). Results. The prevalence of overweight (BMI >85%) increased from 3.2% to 24.4% at 49 months (3-183) (median, range); the BMI SDS increased from -0.27 (0.79) to 0.67 (1.35) after Tx. There was a close correlation between BMI SDS and the percentage of body fat and body fat mass in the Tx group (r = 0.80; r = 0.94, P = .0001). Children with disturbed glycemic control (n = 14) had higher percentage of body fat and higher blood pressure compared with those with normal glucose metabolism (P < .05). There was no difference in pulse wave velocity between the lean and obese patients. Conclusions. The prevalence of overweight or obese patients in the Hungarian pediatric renal cohort is low at transplantation and rises subsequently. Overweight is associated with disturbed glycemic control and increased blood pressure; however, these disturbances are not yet reflected by stiffening of the arteries. Strategies are needed to prevent obesity, its impact on hypertension, and cardiovascular disease in pediatric transplantation.