Associations of body mass index and hospital-acquired disability with post-discharge mortality in older patients with acute heart failure

Objectives: To investigate the effect of hospital-acquired disability (HAD) on all-cause mortality after discharge according to the body mass index (BMI) in older patients with acute decompensated heart failure.

Methods: We included 408 patients aged ≥ 65 years who were hospitalized for acute decompensated heart failure and had undergone an acute phase of cardiac rehabilitation at the Sakakibara Heart Institute between April 2013 and September 2015 (median age: 82 years, interquartile range (IQR): 76-86; 52% male). Patients were divided into three groups based on BMI at hospital admission: underweight (< 18.5 kg/m²), normal weight (18.5 to 25 kg/m²), and overweight (≥ 25 kg/m²). HAD was defined as a decrease of at least five points at discharge compared to before hospitalization according to the Barthel Index.

Results: The median follow-up period was 475 (IQR: 292-730) days, and all-cause mortality during the follow-up period was 84 deaths (21%). According to multivariate Cox regression analysis, being underweight (HR: 1.941, 95% CI: 1.134-3.321,P = 0.016) or overweight (HR: 0.371, 95% CI: 0.171-0.803,P = 0.012), with normal BMI as the reference, and HAD (HR: 1.857, 95% CI: 1.062-3.250,P = 0.030) were independently associated with all-cause mortality. Patients with HAD exhibited a significantly lower cumulative survival rate in the underweight group (P = 0.001) and tended to have a lower cumulative survival rate in the normal weight group (P = 0.072). HAD was not significantly associated with cumulative survival in the overweight group (P = 0.392).

Conclusions: BMI and HAD independently predicted all-cause mortality after discharge in older patients with acute decompensated heart failure. Furthermore, HAD was significantly associated with higher all-cause mortality after discharge, especially in the underweight group.