P6330Obesity paradox in heart failure with mid-range ejection fraction

Abstract

Abstract Background Obesity is identified as an independent risk factor for developing congestive heart failure (HF). Paradoxically it has been reported that obesity is associated with improved survival in different cohorts of HF patients. Nevertheless, the presence of obesity paradox in HF with mid-range ejection fraction (HFmrEF) is not completely elucidated. Objective To analyse the relationship between body mass index (BMI) and mortality in a HFmrEF ambulatory cohort of different aetiologies followed in a HF unit, with especial focus on the role of obesity in prognosis. Methods Baseline BMI was analysed as continuous variable and categorized in 4 groups based on 2009 WHO classification: low weight (BMI <20.5 kg/m2), normal weight (BMI 20.5 to <25.5 kg/m2), overweight (BMI 25.5 to <30 kg/m2) and obesity (BMI ≥30 kg/m2). All-cause mortality was the primary end-point of the study. Cox regression analyses adjusted by age, sex and NYHA functional class were performed and survival curves plotted. Results Three-hundred thirty patients were included in the study (age 65.9±13.2 years, 68% men). The main aetiology was ischemic heart disease (52%, followed by dilated cardiomyopathy (11%) and hypertensive cardiomyopathy (11%). The majority of patients were in NYHA class II (65%) and III (26%). Mean ejection fraction was 43.2% ± 2.7. During a mean follow-up of 5.3±4.6 years 142 patients (42%) died. BMI showed a protective effect on survival in Cox regression analysis (HR 0.96 [95% CI 0.92–0.99], p=0.01). When categorized groups of BMI were analysed, obese patients showed a trend towards lower mortality than normal weight patients (reference): adjusted HR 0.65 [95% CI 0.40–1.03], p=0.07. Survival curves adjusted by age, sex and NYHA functional class according to BMI category are depicted in the figure. As a significant interaction (p=0.02) was found between BMI and ischemic aetiology of HF, separate analyses were performed for BMI categories for ischemic and non-ischemic patients, with remarkably different results: ischemic aetiology: HR 0.97 [95% CI 0.52–1.79], p=0.91; non-ischemic aetiology HR 0.28 [95% CI 0.13–0.64], p=0.003. Conclusions A greater BMI was associated with lower mortality rates in patients with HFmrEF during a mean follow-up of five years. Obesity showed a protective effect in HFmrEF patients, which remarkable in patients from non-ischemic aetiology and was absent in patients from ischemic aetiology.