Population rates of hospitalization for atrial fibrillation/flutter in Canada

Background: Atrial fibrillation (AF) is the most prevalent sustained cardiac dysrhythmia and constitutes a major public health problem. AF significantly increases the risk of stroke, and anticoagulation has been shown to reduce this risk. However, Canadian data on the prevalence of AF and the use of warfarin in these patients are lacking. Methods: International Classification of Diseases, ninth revision, codes for admissions to acute care hospitals in Canada were used to estimate the prevalence of hospitalization for AF between 1997/1998 and 1999/2000, and subsequent readmissions for stroke in all 10 provinces and overall in Canada. Warfarin use was obtained by linkage with drug benefit plans in Alberta, British Columbia, Nova Scotia and Ontario, for patients 65 years and older. Results: The overall rate of hospitalization with AF between April 1, 1997, and March 31, 2000, was 582.7 per 100,000 population. The age- and sex-standardized rate rose from 513.4 to 555.3 during the three-year period of observation. The mean age was 74.4 years and 51.8% of patients were male. Of those discharged alive, 2.7% were readmitted for stroke within one year. Overall, less than one-half of the patients with AF filled a prescription for warfarin within 90 days of discharge, with only a small increase in warfarin use over the study time period. Conclusions: The rate of hospitalization with AF is increasing in Canada and is more frequent in men than in women across all age groups. Consistent with reports from other countries, warfarin use was lower than one might expect given its efficacy, with only a small increase in use over time.