What are the findings of the REDHOT study related to the efficacy of brain natriuretic peptide (BNP) assays?

Updated: Jan 08, 2018
  • Author: Donald Schreiber, MD, CM; Chief Editor: Erik D Schraga, MD  more...
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This investigation indicated that BNP level is a strong predictor of 90-day patient outcome with regard to cardiac mortality and subsequent ED visits and/or rehospitalization for acute CHF.

The Breathing Not Properly investigators undertook the multicenter Rapid Emergency Department Heart Failure Outpatient Trial (REDHOT) to examine the prognostic role of BNP in the ED. [50] They examined baseline BNP levels in 464 patients with dyspnea when they presented to the ED and evaluated its relationship with clinical decision making and with clinical outcomes. Treating physicians were blinded to the BNP levels throughout the study.

The primary outcome measure was the decision to admit or discharge the patient from the ED. A secondary composite 90-day outcome was based on cardiac mortality and subsequent ED visits and/or rehospitalization for acute CHF.

About 90% of patients were admitted. Of interest, baseline BNP levels did not significantly differ between patients who were discharged and those who were admitted. On logistic regression analysis, the decision to admit or discharge a patient and the initial severity of CHF based on the New York Heart Association (NYHA) classification score had no influence on 90-day outcomes. The BNP level was a strong predictor of the 90-day outcome.

Of admitted patients, 11% had BNP levels lower than 200pg/mL; however, the treating ED physician determined that 66% of these patients had disease of NYHA functional class III or IV and that they were at risk for adverse outcomes. The 90-day composite adverse event rate in admitted patients with a BNP level of less than 200pg/mL was 9%, significantly lower than the 29% rate of those admitted with a BNP level of greater than 200pg/mL.

Overall, 26% of all admitted patients had an adverse outcome at 90 days, versus 42% of patients who were discharged. Mortality rates at 90 days between the admitted and discharged groups were not significantly different.

This study highlighted the lack of correlation between the physician’s clinical impression and the BNP level as an objective measure of disease severity. With the high cost of hospitalization and prolonged lengths of stay for CHF patients, the utility of BNP as a triage tool to guide admission decisions merits further study.

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