Background
NT-proBNP (N-terminal pro-
B-type natriuretic peptide) is useful in diagnosis and prognostication in
heart failure (HF). We examined the relationship between
NT-proBNP and outcomes in patients with HF and preserved ejection fraction, with and without
atrial fibrillation (AF). Methods and Results Among 3835 HF with preserved ejection fraction patients enrolled in the I-Preserve (
Irbesartan in
Heart Failure With Preserved Systolic Function trial) or TOPCAT trial (Treatment of Preserved Cardiac Function in
Heart Failure With an
Aldosterone Antagonist), 719 (19%) patients had AF on their baseline ECG. Median (Q1-Q3) levels of
NT-proBNP were 1286 pg/mL (778-2072) in those with AF and 288 pg/mL (122-704) in those without ( P<0.001). We analyzed patients using 4
NT-proBNP bands: <400, 400 to 999 (reference), 1000 to 1999, and ≥2000 pg/mL. The event rates for the primary composite outcome of cardiovascular death or HF hospitalization were higher in patients with AF versus patients without or those without without AF in the lowest
NT-proBNP band (<400 pg/mL; 8.0 versus 3.2 per 100 patient-years), whereas for the higher bands the opposite was true (1000-1999 pg/mL; 11.4 versus 13.2 per 100 patient-years and ≥2000 pg/mL; 17.4 versus 25.6 per 100 patient-years). In adjusted analyses, higher
NT-proBNP levels were less predictive of HF hospitalization than mortality in patients with AF compared with those without. Conclusions Event rates in HF with preserved ejection fraction patients without AF and with
NT-proBNP <400 pg/mL are low. Among patients with
NT-proBNP ≥400 pg/mL, the relationship between
NT-proBNP and outcomes differs with lower absolute risk in patients who have AF compared with those who do not have AF. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifiers: NCT00094302 and NCT00095238.