Prognostic value of high plasma brain natriuretic peptide concentrations in very elderly persons

Background Many elderly persons without heart failure have high plasma concentrations of brain natriuretic peptide (BNP). We investigated the prognostic implications and potential causes of these increased levels. Methods We enrolled 111 persons aged 80 years or older who had no history of hospitalization for cardiac disease, a cardiothoracic ratio ≤55% on chest radiographs, and a serum creatinine level ≤2.0 mg/mL. All subjects had participated in a regular health screening program at our hospital, and were followed for up to 24 months. We studied the correlation of plasma BNP concentration with age, nutritional state, and activities of daily living. Cox proportional hazards models were used to determine the association between BNP levels and clinical outcomes (cardiac hospitalizations, mortality), adjusted for other risk factors. Results During follow-up, 8 subjects (7%) were hospitalized with cardiac disorders, and 21 (19%) died. Each 50-pg/mL increase in the plasma BNP concentration was associated with a 1.6-fold increase in the risk of cardiac events (95% confidence interval [CI]: 1.2 to 2.1) and a 1.4-fold increase in total mortality (95% CI: 1.2 to 1.6). Plasma BNP concentration correlated positively with age (r = 0.31, P = 0.001), serum creatinine level (r = 0.23, P = 0.02), and the activities of daily living (r = 0.36, P = 0.0001). Conclusion In very elderly persons, the plasma BNP concentration may be a biochemical marker of an increased risk of cardiac morbidity and total mortality.