Oral anticoagulation in patients with atrial fibrillation: Adherence with guidelines in an elderly cohort

PURPOSE: To determine adherence with practice guidelines in a population-ba sed cohort of elderly persons aged 70 years or older with atrial fibrillati on. SUBJECTS AND METHODS: This was a cross-sectional analysis of a subgroup of participants in the Cardiovascular Health Study, a prospective observationa l study involving four communities in the United States. Subjects were part icipants with atrial fibrillation on electrocardiogram at one or more yearl y examinations from 1993 to 1995. The outcome measure was self-reported use of warfarin in 1995. RESULTS: In 1995, 172 (4.1%) participants had atrial fibrillation together with information regarding warfarin use and no preexisting indication for i ts use, Warfarin was used by 63 (37%) of these participants. Of the 109 par ticipants not reporting warfarin use, 92 (84%) had at least one of the clin ical risk factors (aside from age) associated with stroke in patients with atrial fibrillation. Among participants not taking warfarin, 47% were takin g aspirin. Several characteristics were independently associated with warfarin use, in cluding age [odds ratio (OR) = 0.6 per 5-year increment, 95% CI 0.5-0.9], a modified mini-mental examination score <85 points [OR = 0.3, 95% confidenc e interval (CI) 0.1-0.9], and among patients without prior stroke, female s ex (OR = 0.5, 95% CI 0.2-1.0). CONCLUSIONS: Despite widely publicized practice guidelines to treat patient s who have atrial fibrillation with warfarin, most participants who had atr ial fibrillation were at high risk for stroke but were not treated with war farin. More studies are needed to determine wily elderly patients with atri al fibrillation are not being treated with warfarin. Am J Med. 1999;106: 16 5-171. (C) 1999 by Excerpta Medica, Inc.