B-type natriuretic peptide in the evaluation and management of dyspnoea in primary care

Objectives. The rapid and accurate diagnosis of heart failure in primary care is a major unmet clinical need. We evaluated the additional use of B-type natriuretic peptide (BNP) levels. Design. A randomized controlled trial. Setting. Twenty-nine primary care physicians in Switzerland and Germany coordinated by the University Hospital Basel, Switzerland. Subjects. A total of 323 consecutive patients presenting with dyspnoea. Interventions. Assignment in a 1:1 ratio to a diagnostic strategy including point-of-care measurement of BNP (n=163) or standard assessment without BNP (n=160). The total medical cost at 3months was the primary end-point. Secondary end-points were diagnostic certainty, time to appropriate therapy, functional capacity, hospitalization and mortality. The final diagnosis was adjudicated by a physician blinded to the BNP levels. Results. Heart failure was the final diagnosis in 34% of patients. The number of hospitalizations, functional status and total medical cost at 3months [median $1655, interquartile range (IQR), 850-3331 vs. $1541, IQR 859-2827; P=0.68] were similar in both groups. BNP increased diagnostic certainty as defined by the need for further diagnostic work-up (33% vs. 45%; P=0.02) and accelerated the initiation of the appropriate treatment (13days vs. 25days; P=0.01). The area under the receiver-operating characteristics curve for BNP to identify heart failure was 0.87 (95% confidence interval, 0.81-0.93). Conclusions. The use of BNP levels in primary care did not reduce total medical cost, but improved some of the secondary end-points including diagnostic certainty and time to initiation of appropriate treatment.