Warfarin Use and Outcomes in Patients With Advanced Chronic Systolic Heart Failure Without Atrial Fibrillation, Prior Thromboembolic Events, or Prosthetic Valves

Warfarin is often used in patients with systolic heart failure (HF) to prevent adverse outcomes. However, its long-term effect remains controversial. The objective of this study was to determine the association of warfarin use and outcomes in patients with advanced chronic systolic HF without atrial fibrillation (AF), previous thromboembolic events, or prosthetic valves. Of the 2,708 BEST patients, 1,642 were free of AF without a history of thromboembolic events and without prosthetic valves at baseline. Of these, 471 patients (29%) were receiving warfarin. Propensity scores for warfarin use were estimated for each patient and were used to assemble a matched cohort of 354 pairs of patients with and without warfarin use who were balanced on 62 baseline characteristics. Kaplan-Meier and Cox regression analyses were used to estimate the association between warfarin use and outcomes during 4.5 years of follow-up. Matched participants had a mean age ± SD of 57 ± 13 years with 24% women and 24% African-Americans. All-cause mortality occurred in 30% of matched patients in the 2 groups receiving and not receiving warfarin (hazard ratio 0.86, 95% confidence interval 0.62 to 1.19, p = 0.361). Warfarin use was not associated with cardiovascular mortality (hazard ratio 0.97, 95% confidence interval 0.68 to 1.38, p = 0.855), or HF hospitalization (hazard ratio 1.09, 95% confidence interval 0.82 to 1.44, p = 0.568). In conclusion, in patients with chronic advanced systolic HF without AF or other recommended indications for anticoagulation, prevalence of warfarin use was high. However, despite a therapeutic international normalized ratio in those receiving warfarin, its use had no significant intrinsic association with mortality and hospitalization.