Warfarin Use And the Risk Of Stroke, Bleeding, And Mortality In Older Adults On Dialysis With Incident Atrial Fibrillation.

AIM: There is conflicting evidence regarding the safety and effectiveness of warfarin for atrial fibrillation (AF) treatment among older end-stage renal disease (ESRD) patients, and differences among subgroups are unclear.

METHODS: Older dialysis patients who were newly diagnosed with AF (7/2007-12/2011) were identified in the United States Renal Data System. The adjusted hazard ratios (HR) of the outcomes (any stroke, ischemic stroke, major bleeding, severe gastrointestinal bleeding, and death) by time-varying warfarin use were estimated using Cox regression accounting for the inverse probability of treatment weight.

RESULTS: Among 5,765 older dialysis patients with incident AF, warfarin was associated with significantly increased risk of major bleeding (HR=1.50, 95% CI 1.33-1.68), but was not statistically associated with any stroke (HR=0.92, 95% CI 0.75-1.12), ischemic stroke (HR=0.88, 95%CI 0.70-1.11) or gastrointestinal bleeding (HR=1.03, 95% CI 0.80-1.32). Warfarin use was associated with a reduced risk of mortality (HR=0.72, 95%CI 0.65-0.80). The association between warfarin and major bleeding differed by sex (male: HR=1.29; 95%CI 1.08-1.55; female: HR=1.67; 95%CI 1.44-1.93; P-value for interaction=0.03).

CONCLUSION: Older ESRD patients with AF who were treated with warfarin had a no difference in stroke risk, lower mortality risk, but increased major bleeding risk. The bleeding risk associated with warfarin was greater among women than men. The risk/benefit ratio of warfarin may be less favorable among older women.