The aim of this study was to describe changes in estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF) and clinical outcomes in a real-world cohort of patients with heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation (AF). A total of 321 patients (67 [58-74] years old, 19.3% females) were included; 134 (41.7%) had AF. AF patients were less frequently prescribed angiotensin receptor-neprilysin inhibitor (ARNi), with no differences concerning sodium-glucose transport protein 2 inhibitors (SGLT2is) and had lower median baseline eGFR values. At 6- and 12-month follow-ups, renal function declined similarly in both groups, with no difference in the proportion of patients experiencing an eGFR decrease of ≥30% from baseline. Regarding cardiac remodeling, patients without AF showed a higher proportion of individuals with an LVEF improvement of ≥10% from baseline, however with no differences between groups in LVEF final recovery. During a median follow-up of 582 (339-1481) days, AF patients showed a higher risk of composite outcome (aHR, 95% CI: 2.12, 1.16-3.86) and of hospitalization for heart failure (hHF) (2.80, 1.44-5.46), without differences in all-cause death. Delta eGFR changes with at least a 30% decline in eGFR were associated with a higher risk of the primary endpoint. Despite lower baseline renal function, AF patients exhibited similar LVEF improvement and renal decline, which emphasizes the importance of guideline-directed medical therapy. AF was associated with a higher risk of adverse events, primarily driven by hHF.
Keywords: atrial fibrillation; guideline-directed medical therapy; heart failure with reduced ejection fraction; left ventricular ejection fraction; renal function.