Abstract
BACKGROUND: Obesity is a worldwide epidemic that has been associated with poor outcomes. Previous studies have demonstrated an inverse relationship between body mass index (BMI) and outcomes, the 'obesity paradox', in several diseases. HYPOTHESIS: We sought to evaluate whether the obesity paradox is present in patients with left ventricular systolic dysfunction (LVSD) of all etiologies, using all-cause mortality as the primary endpoint and hospitalization as the secondary endpoint. METHODS: We conducted a retrospective cohort study of LVSD patients (n = 18 003) seen within the University of Pittsburgh Medical Center network between January 2011 and December 2017. Patients were divided into four BMI categories (underweight, normal weight, overweight, and obese) and stratified by left ventricular ejection fraction (LVEF): <20%, 20-35%, and 35-50%. RESULTS: Over a median follow-up of 2.28 years, higher BMI (mean 28.9 ± 6.8) was associated with better survival for the overall cohort and within LVEF strata (p < .0001). The most common cause of hospitalization was subendocardial infarction among underweight and normal weight patients and heart failure among overweight and obese patients. Cox proportional hazards model showed that BMI, age, and comorbid conditions of diabetes mellitus, chronic obstructive pulmonary disease, chronic kidney disease, and prior myocardial infarction are independent predictors of death. CONCLUSIONS: Our results support the existence of an obesity paradox impacting all-cause mortality in patients with LVSD of ischemic and non-ischemic etiologies even after adjusting for LVEF and comorbidities. Additional research is needed to understand the effect of weight loss on survival once a diagnosis of LVSD is established.