Who receives anticoagulant treatment with warfarin and why? A population-based study in Finland

OBJECTIVE: To ascertain the age and gender distribution of patients receiving anticoagulant (AC) treatment with warfarin, and to establish the prevalence of AC treatment and its indications among the Finnish population. DESIGN: A cross-sectional study in which the patients were identified from the patient records of health centres. SETTING: Primary health care in the Hospital District of South Ostrobothnia in Finland. PATIENTS: Those inhabitants of 15 municipalities in the study area who received AC treatment with warfarin on 1 April 2004. The total number of inhabitants was 132 621 at the end of 2003. MAIN OUTCOME MEASURES: Patient age and gender distributions, the prevalence of AC treatment in the study area, and indications for AC treatment. RESULTS: Altogether 2389 patients were identified, 51.4% of them men. The mean age of the patients was 72.4 years. The prevalence of AC treatment was 1.8%; when age-adjusted to match the Finnish population it was 1.64%. The proportion of men receiving AC treatment was higher than that of women in all age groups. Atrial fibrillation (AF) was the most common main (60.2%) and second (7.2%) indication for AC treatment. CONCLUSION: Compared with Finnish figures 12 years earlier the prevalence of AC treatment has more than doubled, and the proportion of AF among indications has increased from 47% to 67%. New current care guidelines on AF and the increasing proportion of the elderly among the population are probable explanations.