Body mass index, frailty, and outcomes in heart failure with preserved ejection fraction

Relationship between body mass index (BMI), frailty, and clinical adverse events remains unclear in patients with heart failure (HF) with preserved ejection fraction (HFpEF) in different patient populations. We aimed to compare the association of BMI, frailty, and clinical adverse events between a US cohort from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) study and a Chinese cohort from the Heart Failure Registry of Patient Outcomes (HERO) study.

We used data of 1715 participants enrolled from America in the TOPCAT study and 1487 patients with HFpEF in the Chinese registry study, the HERO. We evaluated the relationship between BMI and frailty using multivariate restricted cubic spline logistic regression. Association between frailty and BMI categories and primary outcomes including HF hospitalization, aborted sudden death, and cardiovascular death, all-cause mortality, and HF hospitalization were analysed by Cox proportional hazards models. The patients' mean age was 72 ± 11 years for both study populations, with 50% and 46% female for the TOPCAT study and the HERO study, respectively. Patients in the TOPCAT study had a higher mean BMI (33.9 vs. 24 kg/m²), with 72.3% vs. 52.9% defined as moderately to severely frail (frailty index > 0.3). In the TOPCAT study, risk of frailty rose as BMI increased, but not in the HERO study. Patients with frailty were at significant higher risk for the primary composite outcomes [hazard ratio (HR) 1.84 (95% confidence interval: 1.46-2.32)], all-cause mortality [HR 1.73 (1.34-2.25)], and HF hospitalization [HR 1.83 (1.40-2.40)] in the TOPCAT study. The corresponding numbers in the HERO study were 1.26 (1.01-1.57), 2.21 (1.45-3.35), and 1.15 (0.81-1.37), respectively. The association of frailty with clinical outcomes did not vary with BMI categories in the two studies.

BMI distribution and association between BMI and frailty risk were different between the two study populations. Frailty was associated with clinical adverse events and this association was consistent across different BMI categories in both studies.