Background: The risk-benefit profile of warfarin versus aspirin for patients with heart failure in normal sinus rhythm has not been definitively established. Our objective was to evaluate the overall comparative effects of warfarin and aspirin in patients with heart failure and normal sinus rhythm.
Methods and results: Pubmed, EMBASE, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov from January 1966 to June 2012 were searched to identify relevant studies. We included randomized controlled trials that included comparison of warfarin versus aspirin, and composite end point of death or stroke separately for active treatment and control groups. Summary incidence rates, relative risks (RRs), and 95% confidence intervals (CIs) were calculated using random-effects models. The search identified 4 randomized controlled trials of warfarin versus aspirin therapy, enrolling 3663 patients. There was no significant difference between the 2 treatments for the primary end point (warfarin versus aspirin: RR, 0.94; 95% CI, 0.84-1.06; P=0.31). Warfarin (versus aspirin) was associated with lower risk of any stroke (RR, 0.56; 95% CI, 0.38-0.82; P=0.003) and ischemic stroke (RR, 0.45; 95% CI, 0.24-0.86; P=0.02) but had a neutral effect on death (RR, 1.01; 95% CI, 0.89-1.14; P=0.89) and a higher risk of major bleeding (RR, 1.95; 95% CI, 1.37-2.76; P=0.0002).
Conclusions: Compared with aspirin, warfarin does not provide benefit in the prevention of stroke and death among patients with heart failure in sinus rhythm, but raises the risk of major bleeding; and therefore its use in these patients is not justified.