Abstract P393: Recent Decrease in Ischemic Stroke Mortality in the Netherlands Not Explained by Changes in Incidence

Abstract

Background: The decline in ischemic stroke (IS) mortality in the Netherlands briefly slowed in the 1990s, but then accelerated in the new millennium. IS mortality reflects case fatality, secondary prevention and, crucially, IS incidence. In the present study we determined nationwide IS incidence from 1997 to 2005. Methods: Out-of-hospital deaths for IS were identified in the national cause of death register using ICD-10 codes I63 and I64. First hospitalized IS patients were identified through linkage of the national hospital discharge register and the population register (using ICD-9 codes 434 and 436). We calculated age-sex specific incidence rates and age standardized incidence rates for every year. We identified trends in time series using Mann-Kendall tests. Results: Between 1997 and 2005, we identified 173,293 new IS cases (45% men). Twenty-six percent were out-of-hospital deaths. Age standardized incidence rates increased significantly between 1997 and 2005, from 111 to 119 per 100,000 in 2005 in men, and from 90 to 105 per 100,000 in women (fig 1). Conclusions: Ischemic stroke mortality rapidly declined in the new millennium. This decline however cannot be explained by changes in the incidence of IS which remained stable or even increased between 1997 and 2005. More detailed analysis of trends in case fatality and secondary prevention after IS is therefore needed to examine the welcome decline in IS mortality. However, the increasing trends in IS incidence are worrisome. Recent trends in cardiovascular risk factors should be urgently investigated.