Primary results of the Rapid Emergency Department Heart Failure Outpatient Trial (REDHOT). A multicenter study of B-type natriuretic peptide levels, emergency department decision making, and outcomes in patients presenting with shortness of breath

Abstract

Objectives: The purpose of this study was to examine the relationships among B-type natriuretic peptide (BNP) levels within the diagnostic range, perceived congestive heart failure (CHF) severity, clinical decision making, and outcomes of the CHF patients presenting to emergency department (ED).

Background: Since BNP correlates with the presence of CHF, disease severity, and prognosis, we hypothesized that BNP levels in the diagnostic range offer value independent of physician decision making with regard to critical outcomes in emergency medicine.

Methods: The Rapid Emergency Department Heart failure Outpatient Trial (REDHOT) study was a 10-center trial in which patients seen in the ED with shortness of breath were consented to have BNP levels drawn on arrival. Entrance criteria included a BNP level >100 pg/ml. Physicians were blinded to the actual BNP level and subsequent BNP measurements. Patients were followed up for 90 days after discharge.

Results: Of the 464 patients, 90% were hospitalized. Two-thirds of patients were perceived to be New York Heart Association (NYHA) functional class III or IV. The BNP levels did not differ significantly between patients who were discharged home from the ED and those admitted (976 vs. 766, p = 0.6). Using logistic regression analysis, an ED doctor's intention to admit or discharge a patient had no influence on 90-day outcomes, while the BNP level was a strong predictor of 90-day outcome. Of admitted patients, 11% had BNP levels <200 pg/ml (66% of which were perceived NYHA functional class III or IV). The 90-day combined event rate (CHF visits or admissions and mortality) in the group of patients admitted with BNP <200 pg/ml and >200 pg/ml was 9% and 29%, respectively (p = 0.006).

Conclusions: In patients presenting to the ED with heart failure, there is a disconnect between the perceived severity of CHF by ED physicians and severity as determined by BNP levels. The BNP levels can predict future outcomes and thus may aid physicians in making triage decisions about whether to admit or discharge patients. Emerging clinical data will help further refine biomarker-guided outpatient therapeutic and monitoring strategies involving BNP.