Relation of renal dysfunction to the increased risk of stroke and death in female patients with atrial fibrillation

Abstract

Female patients with atrial fibrillation (AF) are at increased risk of stroke. It is unclear what contributes to the gender-related differences in stroke and mortality amongst AF patients. This is pertinent since oral anticoagulation use results in a significant reduction in stroke, as well as all-cause mortality. We investigated gender-related risk factors for stroke and mortality in a cohort of Chinese patients with AF. We studied 1034 AF patients (27% females, median age 75 years) who were followed-up for an average of 1.9 years for the principal primary endpoint of 'ischaemic stroke and death'. Gender-specific effect of risk factors for stroke and death was analyzed. Patients at high stroke risk (CHADS2 or CHADS2-VASc ≥ 2) and HAS-BLED ≥ 3 had higher rates of ischaemic stroke and death, but ischaemic stroke rates in females with HAS-BLED ≥ 3 did not differ between CHADS2 0-1 and ≥ 2 (~3 per 100 person-years). On multivariate analysis of non-anticoagulated patients (n=885), independent predictors of 'ischaemic stroke and death' in both males and females were age>75, prior stroke and renal dysfunction (all p<0.05). Independent predictors of 'ischaemic stroke' in females were prior stroke, vascular disease and renal dysfunction (all p<0.05). When females were compared to males, adjusted for baseline characteristics, independent predictors for 'ischaemic stroke and death' amongst females were prior stroke (hazard ratio, HR 2.40; 95% confidence interval, CI, 1.17-4.91, p=0.017) and renal dysfunction (HR 5.30; 95%CI 2.39-11.74, p<0.001). When females were compared to males, renal dysfunction remained a predictor for the secondary endpoints of ischaemic stroke (HR 4.37, p=0.05) and all-cause mortality (HR 4.15, p=0.003). Renal dysfunction may be a contributor to the greater risk of stroke and death in female Chinese patients with AF. This increased risk is largely driven by the impact on all-cause mortality.