The "Obesity Paradox" in Patients With HFpEF With or Without Comorbid Atrial Fibrillation

Background: Overweight and mildly obese individuals have a lower risk of death than their normal-weight counterparts; this phenomenon is termed "obesity paradox." Whether this "obesity paradox" exists in patients with heart failure (HF) or can be modified by comorbidities is still controversial. Our current study aimed to determine the association of body mass index (BMI) with outcomes with patients with HF with preserved ejection fraction (HFpEF) with or without coexisting atrial fibrillation (AF). Methods: Patients with HFpEF from the Americas in the TOPCAT trial were categorized into the 3 groups: normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obesity (≥30 kg/m²). The Cox proportional-hazards models were used to calculate the adjusted hazard ratios (HRs) and CIs. Results: We identified 1,749 patients with HFpEF, 42.1% of which had baseline AF. In the total population of HFpEF, both overweight (HR = 0.59, 95% CI: 0.42-0.83) and obesity (HR = 0.49, 95% CI: 0.35-0.69) were associated with a reduced risk of all-cause death. Among patients with HFpEF without AF, overweight (HR = 0.51, 95% CI: 0.27-0.95) and obesity (HR = 0.64, 95% CI: 0.43-0.98) were associated with a lower risk of all-cause death. In those with AF, obesity (HR = 0.62, 95% CI: 0.40-0.95) but not overweight (HR = 0.81, 95% CI: 0.54-1.21) was associated with a decreased risk of all-cause death. Conclusions: The "obesity paradox" assessed by BMI exists in patients with HFpEF regardless of comorbid AF. Clinical Trial Registration: https://clinicaltrials.gov, identifier: NCT00094302.