Trends in risk of recurrence after the first ischemic stroke in adults younger than 55 years of age in Sweden

Background: Previous studies on stroke recurrence in younger adults often contain small sample size which makes it difficult to study trends in stroke recurrence over a long period of time. Aims: The aim of the present study was to investigate temporal trends in the risk of recurrence in younger patients with a first ischemic stroke. Methods: All men and women aged 18-54 years who had survived at least 28 days after a first ischemic stroke from 1987 to 2006 were identified in the Swedish Inpatient Register. The patients were stratified into four 5-year periods according to their admission period and were followed up for a total of four years after the index event with regard to recurrent ischemic stroke. A Cox regression model was used to analyze the risk of recurrent ischemic stroke. Results: Of the 17,149 ischemic stroke patients who were identified, 2432 (14.2%) had a recurrent ischemic stroke event within four years. From the first to the last periods (1987-1991 versus 2002-2006), the four-year risk of recurrent ischemic stroke decreased by 55% (hazard ratio 0.45, 95% confidence interval 0.39-0.53) in men and 59% (hazard ratio 0.41, 95% confidence interval, 0.33-0.50) in women. The cumulative four-year risk was 11.8% (95% CI 10.55-13.25) in men and 9.8% (95% CI 8.40-11.46) in women during the last five-year period (2002-2006). Conclusions: The risk of recurrence among younger ischemic stroke patients has decreased over the past 20 years. Despite these improvements, younger patients are still at a high risk for recurrent ischemic stroke.