Abstract

Background: Although some patients with heart failure (HF) with mildly reduced/preserved ejection fraction have low natriuretic peptide levels, there are no large-scale systematic studies of how common these individuals are or what happens to them. Objectives: The purpose of this study was to examine the proportion of patients in the I-PRESERVE (Irbesartan in Heart Failure with Preserved Ejection Fraction) trial with an N-terminal pro–B-type natriuretic peptide (NT-proBNP) level <125 pg/mL, their clinical characteristics, and outcomes. Methods: I- PRESERVE enrolled patients with symptomatic HF and a LVEF ≥45% but who did not have NT-proBNP or body mass index inclusion/exclusion criteria. Baseline NT-proBNP was measured after enrollment but not reported to investigators. The primary outcome in this analysis was the composite of cardiovascular death or HF hospitalization. Results: Overall, 808 of 3,480 patients (23.2%) had NT-proBNP <125 pg/mL. Patients with a low NT-proBNP were younger (68.6 years vs 72.6 years; P < 0.001), were less often men (36.1% vs 40.9%; P = 0.015), and had a higher body mass index (48.4% vs 38.7% obese; P < 0.001) than those with a higher NT-proBNP level. Patients with a low NT-proBNP had less atrial fibrillation (8.5% vs 35.1%; P < 0.001), myocardial infarction, diabetes, chronic obstructive pulmonary disease, and anemia but better kidney function. Patients with a lower NT-proBNP level had less marked echocardiographic abnormalities and were less likely to experience cardiovascular death or HF hospitalization; adjusted HR: 0.35 (95% CI: 0.27-0.46; P < 0.001). However, health status was similarly impaired in patients with lower and higher NT-proBNP levels (median Minnesota Living with Heart Failure Questionnaire 43 vs 43; P = 0.95). Conclusions: Almost one-quarter of patients with HF with mildly reduced/preserved ejection fraction had a low NT-proBNP level. Although these patients have a favorable prognosis, compared to those with a high NT-proBNP level, they have similarly impaired health status which should be a target for treatment.