We read with great interest the article by Mueller et al1 about the cost-effectiveness of B-type natriuretic peptide (BNP) testing in patients with acute dyspnea. Their article addresses a relevant question in the daily clinical practice, not only regarding the cost-effectiveness of BNP testing but also its beneficial effect on patients' prognosis. Indeed, the BNP group showed a reduction in intensive care unit admissions and in the need of ventilation (invasive and noninvasive) compared with the control group.1,2 In this regard we would like to raise the hypothesis that this beneficial effect on prognosis might not be related to BNP use but may be related to different baseline clinical characteristics between the 2 groups. We wonder whether taking into account more objective clinical parameters for dyspnea severity, such as values of arterial blood pressure gases and the exact number of breaths per minute,3,4 could have revealed a significantly different level of clinical severity between the 2 groups. On the same line of reasoning for exclusion, because different baseline clinical profiles between the 2 groups could have influenced the cost-effectiveness results, the authors could try to exclude from their analysis the patients in the most severe conditions, that is, those admitted to the intensive care unit and those treated by ventilation. If after this exclusion the cost-effectiveness analysis still resulted in a significant difference between the 2 groups, it would strongly confirm the utility of BNP testing in the emergency department.
Costantino G, Rusconi AM, Casazza G, Montano N. Utility of B-Type Natriuretic Peptide Testing in the Emergency Department. Arch Intern Med. 2006;166(20):2287. doi:10.1001/archinte.166.20.2287-b