Outcomes in the management of atrial fibrillation: clinical trial results can apply in practice

Background: The benefits of antithrombotic therapy in chronic atrial fibril lation (AF) have been established in clinical trials, but there is a paucit y of data on outcomes in practice. Aims: The objective was to establish a large ongoing database of patients w ith non-valvular AF, to enable the accurate determination of clinical outco mes. Methods: A retrospective review of the medical records for consecutive pati ents who had AF documented on electrocardiogram at the major teaching hospi tal in Tasmania between 1 January 1997 and 30 June 1999 was performed. An e xtensive range of demographic and clinical variables was recorded for all p atients with chronic or paroxysmal non-valvular AF. Results: The 505 patients (60% males) included in the database had a median age of 76 years. According to risk stratification criteria, 79% of the pat ients with previously diagnosed chronic or paroxysmal AF had a high risk of developing stroke at the time of admission to hospital care. However, only one-third (34%) of these patients were receiving warfarin (or warfarin plu s aspirin), with almost one-quarter (24%) receiving no antithrombotic agent . The annual incidence of ischaemic strokes was 3.4% (1.5-6.4%; 95% CI) whe n taking warfarin, compared to 7.0% (5.2-9.4%) for patients not taking warf arin and 7.8% (5.4-11.1%) for patients taking aspirin. The annual incidence of bleeding complications in patients taking warfarin was 14.2% (10.0-19.5 %) overall and 3.4% (1.5-6.4%) for major bleeds. In patients not taking war farin, the overall annual incidence of bleeds was 8.4% (6.3-10.9%) and 3.9% (2.5-5.7%) for major bleeds. Conclusions: Warfarin is underused in patients with AF. In clinical practic e, warfarin confers a similar stroke risk reduction to that observed in tri als, with an increase in incidence of only minor bleeding complications. As pirin did not appear to reduce the risk of stroke.