Background: The objective of this prospective study was to assess the medical and economic long-term effects of using B-type natriuretic peptide (BNP) concentrations in the management of patients with acute dyspnea. Methods: We performed follow-up analysis of the B-Type Natriuretic Peptide for Acute Shortness of Breath Evaluation, a randomized study including 452 patients who presented to the emergency department with acute dyspnea. Participants were randomly assigned to a diagnostic strategy involving the rapid measurement of BNP concentrations (n = 225) or standard assessment (n = 227). Mortality was assessed at 720 days, morbidity and economic data at 360 days. Results: BNP testing induced several important changes in initial patient management, including a reduction in the initial hospital admission rate, the use of intensive care, and initial time to discharge. At 720 days, 172 deaths had occurred. Cumulative all-cause 720-day mortality was not different between the BNP group (37%) and the control group (36%, P = 0.6). Morbidity as reflected by days spent in-hospital at 360 days was significantly lower in the BNP group [median 12 days ([interquartile range 2-28 days)] compared with the control group [median 16 (7-32)] days, P = 0.025]. Functional status was similar in both groups. Economic outcome as quantified by total treatment cost at 360 days was significantly improved in the BNP group (mean $10 144 vs $12 748 in the control group, P = 0.008). Conclusions: Rapid BNP testing in patients with acute dyspnea has no effect on long-term mortality. However, morbidity as quantified by days spent in-hospital and economic outcome are still improved at 360 days. (c) 2007 American Association for Clinical Chemistry.