Stroke, Major Bleeding, and Mortality Outcomes in Warfarin Users With Atrial Fibrillation and Chronic Kidney Disease: A Meta-Analysis of Observational Studies.

Background: The use of warfarin in patients with atrial fibrillation (AF) and chronic kidney disease (CKD) can be problematic because of increased bleeding risk. We performed a systematic review and meta-analysis of observational studies that evaluated the use of warfarin in patients with AF and CKD to evaluate the risks of ischemic stroke/thromboembolism, major bleeding, and mortality.

Methods: PUBMED, EMBASE, CINAHL, ProQuest, and Google Scholar databases were electronically searched through January 12, 2015. Additionally, a manual search was performed for relevant references. Random-effects model was used to estimate the pooled hazard ratio (HR) with 95% CI. CKD was divided into non-end-stage CKD and end-stage CKD (on renal replacement therapy) and separate analyses were performed.

Results: Thirteen publications from 11 cohorts (six retrospective and five prospective) including >48,500 total patients with >11,600 warfarin users were included in the meta-analysis. In patients with AF and non-end-stage CKD, warfarin resulted in a lower risk of ischemic stroke/thromboembolism (HR, 0.70; 95% CI, 0.54-0.89; P = .004) and mortality (HR, 0.65; 95% CI, 0.59-0.72; P < .00001), but had no effect on major bleeding (HR, 1.15; 95% CI, 0.88-1.49; P = .31). In patients with AF and end-stage CKD, warfarin had no effect on the risks of stroke (HR, 1.12; 95% CI, 0.69-1.82; P = .65) and mortality (HR, 0.96; 95% CI, 0.81-1.13; P = .60), but increased the risks of major bleeding (HR, 1.30; 95% CI, 1.08-1.56; P = .005).

Conclusions: Based on this meta-analysis, the use of warfarin for AF may have an unfavorable risk/benefit ratio in patients with end-stage CKD but not in those with non-end-stage CKD.