Comparison of BMI, waist circumference, and waist-to-height ratio for identification of subclinical cardiovascular risk in pediatric kidney transplant recipients.

BACKGROUND: Kidney transplant recipients are at high risk for CV morbidity. However, the measure of obesity that best predicts CV risk has not been established.

OBJECTIVE: A prospective, controlled study was conducted to compare the ability of BMI, WC, and WHr to identify CV risk in pediatric kidney transplant recipients.

METHODS: Transplant recipients, aged 3-20 years, had echocardiogram, CIMT, BMI, WC, WHr, blood pressure, lipids, and leptin measured. Receiver operating characteristic analysis was used to compare the ability of BMI, WC, and WHr to detect a composite adverse CV outcome. Presence of the composite outcome was defined by ≥3 of the following five criteria: (a) LVH, (b) high CIMT, (c) impaired myocardial strain, (d) dyslipidemia, and/or (e) hypertension. Multivariate analysis was conducted by generalized estimating equation regression.

RESULTS: We analyzed 108 visits of 42 transplant recipients. Prevalence of obesity by WHr (43.5%) was higher than BMI (24.1%) and WC (12.0%). Proportion of WHr-obese who met criteria for the adverse CV outcome was higher (62.2%) than BMI (34.6%) and WC-obese (33.3%). Leptin levels were higher in children with obesity. Area under the ROC curve for WHr-obese (0.77) was higher compared to BMI (0.47) and WC (0.48) to detect the CV outcome, P = 0.0006. WHr-obesity was associated with 5.72 increased odds of having the adverse CV outcome, P = 0.0001, while BMI and WC were not significant.

CONCLUSION: WHr is more sensitive than BMI or WC to detect subclinical CV risk and should be included in screening of pediatric kidney transplant recipients.