Warfarin anticoagulation and survival: a cohort analysis from the Studies of Left Ventricular Dysfunction.

ABSTRACT

OBJECTIVES: We sought to evaluate the relation between warfarin anticoagulation and survival and morbidity from cardiac disease in patients with left ventricular (LV) dysfunction. BACKGROUND: Warfarin anticoagulation plays a major role in the management of patients who have had a large myocardial infarction and in those with atrial fibrillation. However, its use in patients with LV systolic dysfunction has been controversial. METHODS: We reviewed data on warfarin use in 6,797 patients enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) trial and analyzed the relation between warfarin use and all-cause mortality, as well as the combined end point of death or hospital admission for heart failure. We used Cox regression to adjust for differences in baseline characteristics and to test for the interaction between warfarin use and selected patient variables in relation to outcome. RESULTS: On multivariate analysis, use of warfarin was associated with a significant reduction in all-cause mortality (adjusted hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.65 to 0.89, p = 0.0006) and in the risk of death or hospital admission for heart failure (HR 0.82, 95% CI 0.72 to 0.93, p = 0.0002). Risk reduction was observed when each trial or randomization arm was analyzed separately, as well as in both genders. It was not significantly influenced by the presence of atrial fibrillation, age, ejection fraction, New York Heart Association functional class or etiology. CONCLUSIONS: In patients with LV systolic dysfunction, warfarin use is associated with improved survival and reduced morbidity. This association is primarily due to a reduction in cardiac events and does not appear to be limited to any particular subgroup.