Atrial fibrillation in older stroke patients: Association with recurrence and mortality after first ischemic stroke

OBJECTIVES: The objective of this study was to determine the association of atrial fibrillation (AF) with stroke recurrence and mortality and with the causes of death in ischemic stroke patients aged 75 years and older. DESIGN: A population-based study. SETTING: The cities of Turku and Kuopio in Finland. PARTICIPANTS: The study cohort consisted of 2635 consecutive patients aged 75 years and older, with a first ischemic stroke, registered in the FINMONICA Stroke Register. MEASUREMENTS: 28-day and 1-year stroke mortality, causes of death, and recurrence of stroke. RESULTS: There were 767 stroke patients with AF (mean age 82.2) and 1868 patients without AF (mean age 81.4). Mortality was higher in the AF group both 28 days (33.9% vs 28.1%, P = .003) and 1 year after the attack (52.7% vs 43.0%, P < .001). The age-and sex-adjusted relative risk of death at 28 days was 1.25 in the AF group (95% confidence interval (CI) 1.04-1.50, P = .018), and at 1 year it was 1.41 (95% CI 1.18-1.67, P < .001). In a Cox proportional hazards model, 1-year mortality risk comparing the AF-group with non-AF group was 1.24 (95% CI 1.10-1.39, P < .001). The strongest risk factor predicting 1-year mortality was recent myocardial infarction (MI) (RR 1.90, 95% CI 1.49-2.42). Myocardial infarction was more often the underlying cause of death in the AF group during the period of 28 days, but not from 28 days up to 1 year. The 1-year recurrence rate among those alive at day 28 was 11.5% in the AF group and 9.4% in the non-AF group (P = .240). CONCLUSION: Recent MI and AF are independent negative prognostic factors in older patients with stroke. Although the relative risk estimates attributable to AF are of the same magnitude in older as in middle-aged stroke patients, the much higher prevalence of AF in the older patients emphasizes its absolute impact on the mortality and recurrence after the first ischemic stroke in the age group 75 years and older. The treatment of coexisting cardiac disease also has the potential to prevent deaths and recurrent stroke events in older persons.