Plasma brain natriuretic peptide level in older outpatients with heart failure is associated with physical frailty, especially with the slowness domain

OBJECTIVE To determine the association between plasma brain natriuretic peptide (BNP) level in patients with heart failure (HF) and physical frailty as well as with each domain of physical frailty. METHODS Two hundred and six outpatients of cardiovascular medicine aged 60 years and older who had been hospitalized for HF or had been given a prescription medication for HF were included. Physical frailty was assessed using the following five domains: slowness, weakness, exhaustion, low activity, and shrinking, according to the Cardiovascular Health Study. Patients were divided into nonfrailty and frailty groups according to frailty scores. Plasma BNP level was measured. The 6-min walk test was performed to measure endurance. RESULTS Plasma BNP was significantly different between the two groups (frailty group: 158.0 ± 214.7 pg/mL, nonfrailty group: 65.2 ± 88.0 pg/mL, P < 0.01). Multivariate logistic regression analysis revealed log-transformed plasma BNP (Log BNP) was significantly associated with physical frailty (OR: 1.68, 95% CI: 1.11-2.56), and Log BNP was significantly associated with the slowness domain (walking speed < 1.0 m/s) of physical frailty (OR: 1.75, 95% CI: 1.15-2.67). Additionally, Log BNP was negatively correlated to the 6-minute walk distance (6MWD) (ρ = -0.37, P < 0.01), while 6MWD was positively correlated to walking speed (ρ = 0.66, P < 0.01). CONCLUSIONS Plasma BNP level was related to physical frailty, especially in the slowness domain. Endurance may intervene in the associations between plasma BNP level and walking speed.