Atrial fibrillation and stroke. Mortality and causes of death after the first acute ischemic stroke

Abstract

Background and purpose: Atrial fibrillation (AF) is a risk factor for stroke. This study was undertaken to determine the influence of AF on the mortality of stroke patients and on the causes of death after a stroke event.

Methods: Patients with first ischemic stroke who were .35 to 74 years old and registered in the FINMONICA stroke register during 1982 through 1992 were analyzed (n = 6912). There were 642 patients with AF (9.3%) (mean age, 67 years) and 6270 patients without AF (90.3%) (mean age, 63 years). The association between AF and stroke mortality was investigated by use of logistic regression and Cox proportional hazards models.

Results: Mortality was higher in the AF group both at 28 days (19.5% versus 14.4%, P < .001) and 1 year after the attack (30.5% versus 21.8%, P < .001). After adjustment for age and sex, the odds ratio for 28-day case fatality (AF versus non-AF) was 1.27 (95% CI, 1.03 to 1.56; P = .003), and that for 1-year mortality was 1.36 (95% CI, 1.14 to 1.63; P < .001). In the proportional hazards model, AF was a significant independent risk factor for 1-year mortality (hazard ratio, 1.26; 95% CI, 1.09 to 1.46; P = .002). Cardiac causes of death were more common in the AF group at the acute stage. In the course of 1 year, there were no differences in the distributions of causes of death.

Conclusions: Stroke patients with AF are at high risk of death both at the acute phase of stroke and during the subsequent year after the first acute stroke event. Mortality from cardiac diseases prevailed in the AF group during the acute phase of stroke. Careful cardiac evaluation and treatment are essential in patients with AF and stroke.