Relation of body mass index to mortality after development of heart failure due to acute coronary syndrome

Abstract

Several studies have suggested that obesity may be associated with a survival advantage in heart failure (HF). The duration of HF likely influences disease severity and may introduce lead-time bias into analyses of outcomes. The aim of this study was to analyze a cohort in which the exact time of HF onset could be determined: patients in the University of Michigan subset of the acute coronary syndromes (ACS) database of the Global Registry of Acute Coronary Events (GRACE) who developed new-onset HF (no history of HF and left ventricular ejection fraction <or=40% or qualitatively diminished) with their index ACS events from January 1999 to March 2006 (n = 446). For analysis, body mass index (BMI) was categorized as normal (18.5 to <25 kg/m(2)), overweight (25 to <30 kg/m(2)), and obese (>or=30 kg/m(2)). Underweight patients (BMI <or=18.5 kg/m(2)) were excluded. Separate multivariate Cox regression models were performed to examine the effect of BMI group and other potential confounders on all-cause mortality and on the combined outcome of all-cause death, cardiac transplantation, or ventricular assist device implantation. BMI groups were not associated with different risks for the combined outcome, although overweight BMI approached statistical significance for lower risk for the combined outcome. Overweight BMI was significantly associated with lower risk for all-cause death (hazard ratio 0.63, 95% confidence interval 0.42 to 0.94, p = 0.02), although obese BMI was not (hazard ratio 1.06, 95% confidence interval 0.69 to 1.64, p = 0.8). In conclusion, these findings suggest a U-shaped relation between mortality and BMI in the setting of new-onset HF after ACS.