Comparative Renal Outcomes and Effectiveness of Non-Vitamin K Antagonist Oral Anticoagulants Versus Warfarin in Nonvalvular Atrial Fibrillation: Insights from Real-World Data

<i>Background and Objectives</i>: While non-vitamin K antagonist oral anticoagulants (NOACs) show better renal preservation than warfarin in nonvalvular atrial fibrillation (NVAF) patients, real-world evidence within Asian populations remains limited. This study compared the renal outcomes between NOACs and warfarin in Thai patients with NVAF. <i>Materials and Methods</i>: A retrospective cohort study was conducted among NVAF patients who received either NOACs or warfarin from two university hospitals in Thailand from January 2015 to December 2019. The primary outcome was a ≥30% decline in the estimated glomerular filtration rate (eGFR) with a doubling of the serum creatinine (SCr), while acute kidney injury (AKI) and incidence rate of stroke and systemic embolism event (SEE) were secondary outcomes. All outcomes of each NOAC versus the warfarin group were analyzed using Cox proportional hazards regression. <i>Results</i>: A total of 1456 patients were enrolled. During a follow-up period of 24 months, NOACs were associated with a lower risk of a ≥30% decline in the eGFR than warfarin after inverse probability of treatment weighting (IPTW) and multivariable adjustment (adjusted hazard ratio (aHR) of 0.67, 95% confidence interval [CI] 0.45-1.00, <i>p</i> = 0.050). No significant differences were observed between NOACs and warfarin regarding the doubling of SCr (aHR 0.64, 95% CI 0.24-1.72, <i>p</i> = 0.373) or AKI (aHR 0.69, 95% CI 0.41-1.17, <i>p</i> = 0.169), although a trend toward a lower risk was noted in the NOAC group. Similarly, a trend toward a lower risk of the incidence rate of ischemic stroke and SEE were observed in the NOAC group (aHR 0.49, 95% CI 0.22-1.10, <i>p</i> = 0.084). <i>Conclusions</i>: In real-world data, NOACs may be associated with a lower eGFR decline and lower doubling of SCr and AKI than warfarin. Additionally, NOACs may reduce the risk of ischemic stroke and SEE, supporting their potential benefit over warfarin in both renal and thromboembolic outcomes.