Effect of oral anticoagulant therapy on mortality in end-stage renal disease patients with atrial fibrillation: a prospective study

Background: The aim of this study was to evaluate, in a cohort of haemodialysis patients with atrial fibrillation (AF), the relationship between oral anticoagulant therapy (OAT) and mortality, thromboembolic events and haemorrhage. Methods: Two hundred and ninety patients with AF were prospectively followed for 4 years. Warfarin and antiplatelet intake, age, dialytic age, comorbidities, CHA2DS2-VASc and HAS-BLED scores were considered as predictors of risk of death, thromboembolism and bleeding events. In patients taking OAT, the international normalized ratio (INR) was assessed and the percentage time in the target therapeutic range (TTR) was calculated. Results: At recruitment, 134/290 patients were taking warfarin. During follow-up there were 170 deaths, 28 thromboembolic events and 95 bleedings. After balancing for treatment propensity, intention-to-treat analysis on OAT intake at recruitment did not show differences in total mortality, thromboembolic events and bleedings, while the as-treated analysis, accounting for treatment switch, showed that patients taking OAT at recruitment had a significantly lower mortality than those not taking it [hazard ratio, HR 0.53 (95% confidence interval 0.28–0.90), p = 0.04], with a decrease of thromboembolic events [HR 0.36 (0.13–1.05), p = 0.06], and an increase of bleedings [HR 1.79 (0.72–4.39), p = 0.20], both non-significant. Among patients taking OAT at recruitment, those continuing to take warfarin had a significant reduction in the risk of total [HR 0.28 (0.14–0.53), p < 0.001] and cardiovascular [HR 0.21 (0.11–0.40), p < 0.001] mortality compared to patients stopping OAT. Conclusions: In haemodialysis patients with AF, continuously taking warfarin is associated with a reduction of the risk of total and cardiovascular mortality.