Inverse association of mortality and BMI in patients with cardiomyopathy of any etiology

Abstract

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 patients' outcomes, the “obesity paradox”, in several diseases. Purpose We sought to evaluate whether the obesity paradox applies to cardiomyopathy patients of all etiologies, using all-cause mortality as the primary endpoint. Methods We conducted a retrospective study of cardiomyopathy patients (n=18,003) seen within the UPMC network between January 2011 and December 2017. Patients were divided into 4 BMI categories (underweight, normal weight, overweight, and obese) and stratified by left ventricular ejection fraction (LVEF): <20%, 20–35%, and 36–50%. A Cox proportional hazards model was created to assess the independent predictive value of BMI on mortality. Results Over a median follow-up of 2.28 years, higher BMI was associated with better survival for the overall cohort (Figure) and within LVEF strata (p<0.0001). 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 COPD, CKD, and CAD are independent predictors of death. Conclusion Our results support the existence of an obesity paradox impacting all-cause mortality in cardiomyopathy patients of all etiologies even after adjusting for LVEF. Additional research is needed to understand the effect of weight loss on survival once a diagnosis of cardiomyopathy is established. Figure 1. Kaplan-Meier Survival Estimates Funding Acknowledgement Type of funding source: None