Obesity paradox in Korean male and female patients with heart failure: A report from the Korean Heart Failure Registry

Background: Although the survival benefit of obesity has been suggested in patients with heart failure (HF), the impact of sex on obesity paradox is less clear. This study was performed to investigate whether there is a sex difference in the association between body mass index (BMI) and long-term clinical outcomes in patients hospitalized for HF.

Method: A total of 2616 patients hospitalized for HF (Mean age 66 years and 52% males) from the nation-wide registry database were analyzed. Patients were categorized using baseline BMI as normal (18.5 to 22.9 kg/m²), overweight (23 to 27.4 kg/m²) and obese (≥ 27.5 kg/m²). Their all-cause mortality and long-term composite events, including all-cause mortality and HF readmission, were assessed according to the BMI groups.

Results: During the median follow-up period of 1499 days, there were 662 patients (25.3%) with all-cause mortality and 1071 patients (40.9%) with composite events. Compared to the normal weight group, the overweight (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.51-0.99; P = 0.045) and obese (HR, 0.53; 95% CI, 0.29-0.95; P = 0.032) group showed lower all-cause mortality rates even after adjusting for confounding factors in the male patients. Otherwise, BMI was not associated with composite events in males; it was not associated with all-cause mortality or composite events in females in the multivariable analyses (P > 0.05 for each).

Conclusions: Among patients with HF, a greater BMI was associated with low all-cause mortality in males, but not in females. Obesity paradox should be considered in the management of HF patients.