OBESITY, METABOLIC SYNDROME, AND CARDIOVASCULAR OUTCOMES IN PEDIATRIC KIDNEY TRANSPLANT RECIPIENTS

Abstract

Cardiovascular (CV) disease is a leading cause of morbidity amongst children after kidney transplant. The contribution of abdominal obesity and metabolic syndrome (MS) to CV risk is not well defined in this population. A prospective controlled longitudinal cohort study was conducted to investigate contributions of obesity and MS to CV morbidity in a multiracial pediatric kidney transplant population. Aims of the study were to 1) identify prevalence of CV and metabolic abnormalities 2) evaluate effects of obesity and MS on adverse CV outcomes, defined by left ventricular hypertrophy (LVH), impaired myocardial strain and increased carotid intima-media thickness (CIMT) and 3) identify the anthropometric measure of obesity, Body Mass Index (BMI), Waist-to-Height ratio (WHr), or Waist Circumference (WC), that best predicts CV risk. Transplant recipients had standard echocardiographic measures of left ventricular size and function, strain by speckle tracking echocardiography, and CIMT measured at 1, 18, and 30 months post-transplant. 35 pre-transplant echocardiograms were analyzed retrospectively. Multivariate longitudinal regression was used to determine associations of obesity and MS with CV outcomes. Results indicated obesity and MS are prevalent among pediatric kidney transplant recipients. WHr is a more sensitive indicator of obesity-associated adverse CV outcomes compared with BMI or WC, due in part to the prevalence of short stature in this population. Obesity, MS, and hypertension are associated with post-transplant LVH. Significant predictors of impaired longitudinal strain include obesity, hypertension, and a combination of MS with elevated LDL-C cholesterol, whereas higher estimated glomerular filtration rate confers a protective effect. African American pediatric kidney transplant recipients have increased CIMT, which is negatively impacted by MS, whereas the CIMT of non-African American children appears unaffected after transplant. In conclusion, obesity and MS adversely affect CV outcomes in pediatric kidney transplant recipients, highlighting the importance of efforts to maintain healthy weight, blood pressure, and lipid profile after transplant. Further studies are needed to investigate the etiology and consequences of increased CIMT in African American transplant recipients. Imaging techniques such as speckle tracking echocardiography and CIMT may provide a means of detecting subclinical myocardial dysfunction and provide opportunity for early intervention in this population.