Obesity, brain natriuretic peptide levels and mortality in patients hospitalized with heart failure and preserved left ventricular systolic function.

BACKGROUND: An inverse relationship between brain natriuretic peptide (BNP) levels and body mass index (BMI) has been described for patients with left ventricular (LV) systolic dysfunction. In this study, the association of BMI, BNP levels and mortality in patients hospitalized for heart failure with preserved LV systolic function (HFpLVF) was investigated.
METHODS: One hundred fifty consecutive patients (98% men) who were hospitalized with HFpLVF and had BNP levels measured on admission were analyzed. Patients were divided into categories of BMI: normal (BMI < 25 kg/m), overweight (BMI 25-29.9 kg/m) and obese (BMI ≥ 30 kg/m). Relevant clinical and echocardiographic characteristics and all-cause mortality were obtained through chart review.
RESULTS: BNP levels were significantly lower in obese (median = 227 pg/mL) and overweight (median = 396 pg/mL) patients compared with those with normal BMI (median = 608 pg/mL, P = 0.003). Higher BMI predicted BNP levels of <100 pg/mL. Compared with patients with normal BMI, overweight and obese patients had a significantly lower risk of total mortality, even after adjusting for other clinical characteristics, including log-transformed BNP levels, atrial fibrillation, the use of beta-blockers at discharge, age, hemoglobin levels and the presence of pulmonary congestion on admission. Higher BNP levels also independently predicted mortality.
CONCLUSIONS: An inverse relationship between BMI and BNP levels exists in patients hospitalized with HFpLVF. Higher BMI is associated with lower mortality, whereas higher BNP levels predict higher mortality in male patients with HFpLVF. These findings should be confirmed in a larger multicenter setting.