Warfarin slows deterioration of renal function in elderly patients with chronic kidney disease and atrial fibrillation

BACKGROUND: The purpose of this study was to examine whether long-term use of anticoagulants in elderly patients with atrial fibrillation (AF) and chronic kidney disease (CKD) influences renal function. METHODS: In this retrospective observational study, we reviewed the records of 2023 patients who attended our institution for treatment of CKD between January 2001 and September 2012. Inclusion criteria were having been under review for three months or more, age older than 60 years, permanent AF, a CHADS2 score > 2, and National Kidney Foundation Kidney Disease Outcomes Quality Initiative CKD stage 3-5. Sixty-one patients fulfilled these criteria, and were divided into those receiving antiplatelet anticoagulation (group A) and those receiving warfarin (group B). The results of laboratory investigations and estimated glomerular filtration rate (GFR) were recorded at months 3, 6, 12, and 18 from treatment initiation. We also recorded the occurrence of serious cardiovascular and neurological events, significant bleeding, and survival beyond 12 years. RESULTS: Of the 61 patients enrolled, 35 were in group A and 26 were in group B. The mean international normalized ratio (INR) was 1.95 ± 1.01 (goal < 3.0). After adjustment for potential confounding variables, we found that patients in group B had a higher estimated GFR (6.06 ± 2.36 mL per minute, P = 0.01). Over a 12-year observation period, group B patients had significantly (P = 0.013) better survival than group A, with an adjusted hazard ratio for mortality of 0.318 (P = 0.022). CONCLUSION: Warfarin therapy may delay deterioration in renal function and improve survival of elderly patients with CKD and AF.