Testing for BNP and NT-proBNP in the diagnosis and prognosis of heart failure.

OBJECTIVES The purpose of this systematic review was to evaluate BNP and NT-proBNP to: (a) identify determinants, (b) establish their diagnostic performance in heart failure (HF) patients, (c) determine their predictive ability with respect to mortality and other cardiac endpoints, and (d) determine their value in monitoring HF treatment. DATA SOURCES MEDLINE, EMBASE, CINAHL, Cochrane Central, and AMED from 1989 to February 2005 were searched for primary studies. REVIEW METHODS Standard systematic review methodology, including meta-analysis, was employed. All study designs were included. Eligibility criteria included English-only studies and restricted the number of test methods to maximize generalizability. Outcomes for prognosis were limited to mortality and specific cardiac events. Further specific criteria were developed for each research question. RESULTS Determinants: There were 103 determinants identified including age, gender, disease, treatment, as well as biochemical and physiological measures. Few studies reported independent associations and of those that did age, female gender and creatinine levels were positively associated with BNP and NT-proBNP. DIAGNOSIS Pooled sensitivity and specificity values were 94 and 66 percent for BNP and 92 and 65 percent for NT-proBNP; there was minimal difference among settings (emergency, specialized clinics, and primary care). B-type natriuretic peptides also added independent diagnostic information above traditional measures for HF. PROGNOSIS Both BNP and NT-proBNP were found to be independent predictors of mortality and other cardiac composite endpoints in patients with risk of coronary artery disease (CAD) (risk estimate range = 1.10 to 5.40), diagnosed CAD (risk estimate range = 1.50 to 3.00), and diagnosed HF patients (risk estimate range = 2.11 to 9.35). With respect to screening, the AUC values (range = 0.57 to 0.88) suggested poor performance. Monitoring Treatment: Studies showed therapy reduced BNP and NT-proBNP, however, relationship to outcome was limited and not consistent. CONCLUSIONS Determinants: The importance of the identified determinants for clinical use is not clear. DIAGNOSIS In all settings both BNP and NT-proBNP show good diagnostic properties as a rule out test for HF. PROGNOSIS BNP and NT-proBNP are consistent independent predictors of mortality and other cardiac composite endpoints for populations with risk of CAD, diagnosed CAD, and diagnosed HF. There is insufficient evidence to determine the value of B-type natriuretic peptides for screening of HF. Monitoring Treatment: There is insufficient evidence to demonstrate that BNP and NT-proBNP levels show change in response to therapies to manage stable chronic HF patients.