Commentary

Diagnosing acute heart failure in EDs has often been difficult, but recent reports suggest that BNP testing could improve diagnostic accuracy and management.¹ The study by Mueller et al showed that a clinical strategy driven by BNP testing led to equivalent short term mortality and lower overall costs. A reduced hospital admission rate and fewer admissions to the intensive care unit accounted for most of the cost differences. Because all primary data came from a single study conducted in a single centre, BNP testing may not improve management of dyspnoea in other settings. In particular, unblinded BNP test results may have influenced treatment decisions and led to inaccurate inferences. Despite random allocation, the BNP group might have been healthier than the control group because of the relatively small number of patients in the study. However, the authors used a bootstrap analysis to estimate the uncertainty in their results. BNP testing was nearly always cost saving and was the dominant strategy in most analyses (ie, it delivered equal or better clinical outcomes at reduced cost). In addition to any reduction in hospital admissions, BNP testing may have created cost savings by reducing use of more expensive diagnostic tests.

Generalisability might be limited because other centres might not modify patient management as effectively. Cost effective use of BNP testing requires that providers correctly interpret and appropriately act on test results, which may be less common in non-study settings. Further studies are needed in more diverse settings to obtain more definite information on both costs and clinical effectiveness. Larger studies might be able to more confidently exclude the possibility that BNP testing leads to lower costs but higher mortality. None the less, the results indicate that broader use of appropriate BNP testing could improve clinical care while reducing costs from unnecessary tests and hospital admissions.