Outcomes in the management of atrial fibrillation: clinical trial results can apply in practice
Jackson, SL and Peterson, GM and Vial, JH and Daud, R and Ang, SY, Outcomes in the management of atrial fibrillation: clinical trial results can apply in practice, Internal Medicine Journal, 31, (1) pp. 329-336. ISSN 1444-0903 (2001) [Refereed Article]
Background: The benefits of antithrombotic therapy in chronic atrial fibrillation (AF) have been established in clinical trials, but there is a paucity of data on outcomes in practice.
Aims: The objective was to establish a large ongoing database of patients with non-valvular AF, to enable the accurate determination of clinical outcomes.
Methods: A retrospective review of the medical records for consecutive patients who had AF documented on electrocardiogram at the major teaching hospital in Tasmania between 1 January 1997 and 30 June 1999 was performed. An extensive range of demographic and clinical variables was recorded for all patients 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 patients 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 plus 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) when taking warfarin, compared to 7.0% (5.2–9.4%) for patients not taking warfarin 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 warfarin, 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 practice, warfarin confers a similar stroke risk reduction to that observed in trials, with an increase in incidence of only minor bleeding complications. Aspirin did not appear to reduce the risk of stroke. (Intern Med J 2001; 31: 329–336)