Community-based stroke incidence in a Scottish population - The Scottish Borders Stroke Study

Background and Purpose - The purpose of this study was to determine the incidence and case fatality of stroke in a geographically defined region of Scotland, a nation with a high cardiovascular risk. Methods - All strokes occurring in residents of the Scottish Borders (population 106 352) were identified during a 24-month period from 1998 to 2000 using multiple overlapping methods of case-ascertainment. Standard criteria were used to define stroke and case fatality. Stroke subtypes were determined by computer tomography (CT) scan, MRI, or autopsy. Results - 790 strokes were identified; 596 were first-ever-in-a-lifetime strokes (FES). 91.1% of FES underwent CT scan and/or autopsy. The crude annual incidence rate per 100 000 per year was: 280 (95% CI, 258 to 304) overall, 197 (95% CI 179 - 217) cerebral infarction, 24 (95% CI 17 - 31) intracerebral haemorrhage, 11 ( 95% CI 7 - 16) subarachnoid haemorrhage and 49 (95% CI 40 - 59) undetermined stroke. 28 day FES case fatality was 15.9% (95% CI, 13.2 to 19.1) increasing to 26.3% (95% CI, 23.0 to 30.0) at 1 year. Comparing 18 previous worldwide incidence studies with the SBSS showed a similar relative risk of stroke incidence and case fatality for FES and FES subtypes. Conclusions - The SBSS crude incidence rate is one of the highest in the world but age-adjusted rates, case fatality and relative risk for all stroke and stroke subtypes were not significantly different from the majority of previous studies. Unlike cardiovascular disease, the Scottish risk of stroke would appear to be similar to other populations worldwide.