The obesity paradox in super-elderly patients with heart failure: a retrospective cohort study

Obesity is an independent risk factor for heart failure (HF) onset; however, weight loss is an independent poor prognostic factor in patients with HF. According to the obesity paradox, higher body weight is associated with better prognosis in these patients. This retrospective cohort study investigated the obesity paradox in super-elderly, understudied patients (aged ≥ 85 years) with HF and examined its impact on all-cause mortality. We included patients hospitalized for HF between April 2015 and March 2023. Participants were divided into four age groups: Groups A (< 65 years), B (65-74 years), C (75-84 years, elderly), and D (≥ 85 years, super-elderly). The primary endpoint was the 1-year all-cause mortality rate after discharge. The secondary endpoints included cardiac and non-cardiac death rates and all-cause mortality rates stratified by left ventricular ejection fraction (LVEF). Overall, 3,811 individuals (mean age: 74.3 years, 60.4% men) were included. A trend toward higher all-cause mortality rates associated with underweight (body mass index [BMI] < 18.5 kg/m²) was observed in all age groups. Patients with obesity (BMI ≥ 25.0 kg/m²) had significantly better survival than other patients. Underweight was associated with a higher cardiac death rate compared with the other weight categories (P = 0.014, 0.039, and 0.022 for groups B, C, and D, respectively). In the analysis stratified by LVEF, underweight was significantly associated with a higher cardiac death rate in patients with HF with preserved LVEF compared with the other weight categories (P < 0.001). The obesity paradox in the super-elderly population was confirmed. It is important to consider BMI in HF management and prognosis.