Baseline Plasma NT-proBNP and Clinical Characteristics: Results From the Irbesartan in Heart Failure With Preserved Ejection Fraction Trial

BACKGROUND: N-terminal B type natriuretic peptide (NT-proBNP) is usually elevated in heart failure (HF) patients with reduced ejection fraction (EF). Less is known about NT-proBNP in HF with preserved EF (HF-PEF). We measured baseline NT-proBNP in 3562 HF-PEF enrolled patients in the Irbesartan in Heart Failure with Preserved Ejection Fraction trial. METHODS AND RESULTS: Patients with EF >or=45%, age >or=60 years, and either New York Heart Association (NYHA) II-IV symptoms with HF hospitalization (HFH) within 6 months or NYHA III-IV symptoms with corroborative evidence of HF or structural changes associated with HF-PEF. NT-proBNP (pg/mL) measured centrally using the Elecsys proBNP assay (Roche). Mean age 72 +/- 7 years, 60% were women, the investigator indicated HF etiology was hypertension in 64%; the majority were in NYHA III. Medications included diuretics in 82%, angiotensin-converting enzyme inhibitor in 26%, beta-blocker in 59%, and spironolactone in 15%. Median NT-proBNP was 341 pg/mL (interquartile range 135 to 974 pg/mL) and geometric mean was 354 pg/mL. In multivariate analysis, the baseline characteristics most strongly associated with higher NT-proBNP levels were atrial fibrillation (ratio of geometric mean 2.59, P < .001), NYHA IV symptoms (1.52, P < .001), lower estimated glomerular filtration rate (1.44, P < .001), and HFH hospitalization within 6 months (1.37, P < .001). CONCLUSIONS: Most HF-PEF patients have elevated NT-proBNP levels. The NT-proBNP concentrations were related to baseline characteristics generally associated with worse outcomes for HF patients.