Association of Body Mass Index and Abdominal Obesity with Incidence of Atrial Fibrillation in Heart Failure with Preserved Ejection Fraction.

INTRODUCTION: The association between obesity and atrial fibrillation (AF) incidence in heart failure with preserved ejection fraction (HFpEF) patients is currently unclear. Our analyses and results are based on the whole Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial (placebo and spironolactone).

METHOD: A total of 2138 subjects without baseline AF were included in the trial. Kaplan-Meier (K-M) curves and Cox regression with hazard ratios (HRs) and confidence intervals (CIs) were used to assess the incidence of AF with obesity. Of 2138 HFpEF patients without baseline AF, 1165 were obese (body mass index [BMI]≥30 kg/m2).

RESULT: The K-M curve showed obese patients developed AF more than overweight (25≤ BMI ≤29.9 kg/m2) patients (p=0.013), confirmed by multivariable analysis, while there's no statistical difference between overweight and normal weight (18.5≤ BMI ≤24.9 kg/m2) patients. The occurrence of AF increased by 3% for every kg/m2 increase in BMI (adjusted HR, aHR: 1.03; 95% CI: 1.00-1.06), with a positive linear association (p for nonlinear: 0.145). Obesity was associated with AF incidence (aHR: 1.62; 95% CI: 1.05-2.50) compared with non-obesity (including overweight and normal-weight patients).

CONCLUSION: Abdominal obesity was associated with increased AF incidence (aHR: 1.70; 95% CI: 1.04-2.77), and AF incidence rose by 18% per centimeter in circumference (aHR: 1.18; 95% CI: 1.04-1.34). Obesity and abdominal obesity increase the incidence of AF in HFpEF patients. Further studies need to determine whether there is a difference in AF in response to spironolactone across obese HFpEF pheno groups.