FAILURE TO PRESCRIBE WARFARIN TO PATIENTS WITH NONRHEUMATIC ATRIAL-FIBRILLATION

OBJECTIVE: To determine how often warfarin was prescribed to patients with nonrheumatic atrial fibrillation in our community in 1992 when ra ndomized trials had demonstrated that warfarin could prevent stroke wi th little increase in the rate of hemorrhage, and to determine whether warfarin was prescribed less frequently to older patients-the patient s at highest risk of stroke but of most concern to physicians in terms of the safety of warfarin. DESIGN: Cross-sectional study. Appropriate ness of warfarin was classified for each patient based on the independ ent judgments of three physicians applying relevant evidence and guide lines. SETTING: Two teaching hospitals and five community-based practi ces. PATIENTS: Consecutive patients with nonrheumatic atrial fibrillat ion (n = 189). MEASUREMENTS AND MAIN RESULTS: Warfarin was prescribed to 44 (23%) of the 189 patients. Warfarin was judged appropriate in 98 patients (52%), of whom 36 (37%) were prescribed warfarin. Warfarin w as prescribed to 11 (14%) of 76 patients aged 75 years or older with h ypertension, diabetes mellitus, or past stroke, the group at highest r isk of stroke. In a multivariable logistic regression model controllin g for appropriateness of warfarin and other patient characteristics, p atients aged 75 years or older were less likely than younger patients to be treated with warfarin (odds ratio 0.25; 95% confidence interval 0.10, 0.65). CONCLUSIONS: Warfarin was prescribed infrequently to thes e patients with nonrheumatic atrial fibrillation, especially the older patients and even the patients for whom warfarin was judged appropria te. These findings indicate a substantial opportunity to prevent strok e.