Atrial fibrillation and risk of stroke in dialysis patients.

OBJECTIVE

Both stroke and chronic atrial fibrillation (AF) are common in dialysis patients, but uncertainty exists in the incidence of new strokes and the risk conferred by chronic AF.

METHODS

A cohort of dually eligible (Medicare and Medicaid) incident dialysis patients was constructed. Medicare claims were used to determine the onset of chronic AF, which was specifically treated as a time-dependent covariate. Cox proportional hazards models were used to model time to stroke.

RESULTS

Of 56,734 patients studied, 5629 (9.9%) developed chronic AF. There were 22.8 ischemic and 5.0 hemorrhagic strokes per 1000 patient-years, a ratio of approximately 4.5:1. Chronic AF was independently associated with time to ischemic (hazard ratio [HR], 1.26; 99% confidence interval [CI], 1.06-1.49; P = .0005), but not hemorrhagic, stroke. Race was strongly associated with hemorrhagic stroke: African Americans (HR, 1.46; 99% CI, 1.08-1.96), Hispanics (HR, 1.64; 99% CI, 1.16-2.31), and others (HR, 1.76; 99% CI, 1.16-2.78) had higher rates than did Caucasians (all P < .001).

CONCLUSIONS

Chronic AF has a significant, but modest, association with ischemic stroke. Race/ethnicity is strongly associated with hemorrhagic strokes. The proportion of strokes owing to hemorrhage is much higher than in the general population.