(35) - High BMI Predicts Poor Outcomes in DCM But Not CHD Patients: The Differential Impact of Obesity on Outcomes in Pediatric Heart Transplantation

Abstract

Body mass index (BMI) is thought to have an important impact on waitlist and post-transplant mortality in children. Our aim was to investigate whether the impact of BMI varies by the etiology of the heart failure. UNOS has 3,254 listings for primary, isolated heart transplant in patients 3-18 yrs old (1995-2012) with either congenital heart disease (CHD) or dilated cardiomyopathy (DCM). Patients were stratified into 4 groups based on BMI%ile-for-age (BMI%): underweight (BMI% < 5), normal weight (5-84), overweight (85-94), or obese (≥ 95). Waitlist and post-transplant outcomes were assessed. Obesity was more common among DCM patients (18.7% vs. 9.91%) while underweight was more common in CHD patients (20.0% vs. 15.7%, p<0.0001). Waitlist survival was unaffected by BMI% category among CHD patients; underweight (HR 1.3, 1.0-1.6) and obese (1.2,1.0-1.5) DCM patients HR 1had worse survival and lower transplantation rates (OR0.6, 0.5-0.8). Overweight DCM (1.8, 0.8-4.2) patients and obese CHD (1.9, 0.9-4.0) patients had higherrisk-adjusted mortality prior to discharge. Overweight (HR 1.6, 1.2-2.2) and obese (1.2, 0.9-1.7) patients had higher 1-yr conditional mortality, whereas obese CHD patients had lower mortality (0.5, 0.3-1.0). Higher BMI% was a significant predictor of coronary allograft vasculopathy (p=0.02), and diabetes (p=0.0006) in DCM (but not CHD) patients (Figure). The impact of BMI% on waitlist and post-transplant mortality varies by diagnosis. Analyses of weight and nutritional status in heart failure and transplantation need to examine CHD and DCM patients separately. BMI alone is insufficient, and better measures of nutrition, causes of increased BMI (obesity vs fluid retention), and physical conditioning are required to better estimate risk.