Relationship between the Renal Function and Adverse Clinical Events in Patients with Atrial Fibrillation: A Japanese Multicenter Registry Substudy

Background: Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist, but the real-world data after approval of direct oral anticoagulants (DOACs) are still lacking in Japan. We investigated the association of the baseline renal function and adverse clinical events and risk of adverse clinical events with DOACs compared to warfarin for each renal functional level in Japanese AF patients. Methods: The present substudy was based on the SAKURA AF Registry, a Japanese multicenter observational registry (median follow-up period: 39 months). The creatinine clearance (CrCl) values were estimated by the Cockcroft–Gault formula, and divided into normal renal function, and mild and moderate-severe CKD (CrCl ≥ 80, 50–79, <50 mL/min). Results: In the SAKURA AF Registry, the baseline CrCl data were available for 3242 patients (52% for DOAC and 48% for warfarin user). The relative risk of adverse clinical events was significantly higher in the patients with a CrCl < 50 mL/min as compared to those with a CrCl ≥ 80 mL/min (adjusted HRs: 2.53 for death, 2.53 for cardiovascular [CV] events, 2.13 for strokes, and 1.83 for major bleeding). Risks of all adverse clinical events were statistically even between DOAC and warfarin users for each renal function level. Conclusion: Moderate–severe CKD was associated with a higher mortality, CV events, strokes, and major bleeding than normal renal function. The safety and effectiveness of DOACs over warfarin were similar for each renal function level. By a worsening renal function, the incidence of adverse clinical events increased, especially deaths and CV events as compared to strokes and major bleeding.