Effects of Atrial Fibrillation on Heart Failure Outcomes and NT-proBNP Levels in the GUIDE-IT Trial

OBJECTIVE: To evaluate effects of atrial fibrillation (AF) on cardiac biomarkers and outcomes in a trial population of patients with heart failure (HF) with reduced ejection fraction treated with optimal guideline-directed medical therapy. METHODS: We performed a secondary analysis of 894 patients in the Guiding Evidence-Based Therapy Using Biomarker-Intensified Treatment in Heart Failure (GUIDE-IT) trial (January 2013–July 2016). Patients were stratified by AF status and compared with regard to guideline-directed medical therapy use, longitudinal levels of N-terminal pro–B type natriuretic peptide (NT-proBNP), and outcomes including HF hospitalization and mortality. RESULTS: After adjustment, AF was associated with a significant increase in the risk of HF hospitalization or cardiovascular death (hazard ratio, 1.28; 95% CI, 1.02 to 1.61; P=0.04) and HF hospitalization (hazard ratio, 1.31; 95% CI, 1.02 to 1.68; P=.03) but with no difference in mortality during a median 15 months of follow-up. There were no significant differences in medication treatment between those with and those without AF. At 90 days, a higher proportion of patients with AF (89.4% vs 81.5%; P=.002) had an NT-proBNP level above 1000 pg/mL (to convert NT-proBNP values to pmol/L, multiply by 0.1182), and AF patients had higher NT-proBNP levels at all time points through 2 years of follow-up. CONCLUSION: Among patients with HF with reduced ejection fraction, prevalent AF was associated with higher NT-proBNP concentrations through 2 years of follow-up and higher risk for HF hospitalization despite no substantial differences in medical therapy.