Diagnostic value of a rapid test for B-type natriuretic peptide in patients presenting with acute dyspnoe: effect of age and gender.

Background: B-type natriuretic peptide (BNP) measurements are useful for diagnosing congestive heart failure (CHF) in patients presenting to the Emergency Department with acute dyspnoe. Whether the diagnostic accuracy of BNP is affected by the age and gender of the patients remains unknown.

Aims: To evaluate the accuracy of BNP testing for diagnosing CHF in an unselected group of patients admitted to the emergency department of a Norwegian teaching hospital with a principal complaint of shortness of breath and to assess whether the diagnostic accuracy of the test differs according to age and gender.

Methods: BNP levels in plasma were determined by a point-of-care device upon arrival in 155 patients presenting with acute dyspnoe. The diagnostic 'gold' standard for CHF was adjudicated by two independent cardiologists who were blinded to the BNP data.

Results: By univariate logistic regression analysis, BNP was strongly related to a diagnosis of CHF. In a multivariate model BNP provided additional prognostic information to patient age and gender, radiographic evidence of pulmonary congestion and cardiomegaly, and the presence of pulmonary rales and jugular vein distention by physical examination. There was no significant interaction between age and BNP or between gender and BNP with regard to the accuracy of diagnosing CHF. The area under the receiver-operating characteristics-curve was 0.86 (95% confidence interval 0.78-0.93) in women and 0.90 (0.82-0.97) in men. The area under the curves were 0.82 (0.73-0.92) and 0.88 (0.80-0.97) for patients (both genders) aged > or = 76 and <76 years, respectively.

Conclusion: Point-of-care BNP measurement in the emergency department discriminates well between patients with dyspnoe of cardiac and non-cardiac origin regardless of age and gender.