High incidence rates of stroke in Orebro, Sweden: Further support for regional incidence differences within Scandinavia

Background and purpose: As a basis for comparison of differences in stroke incidence in Scandinavian countries, a community-based stroke register was established in Orebro in the centre of Sweden.

Methods: All first-ever cases of stroke were registered during a 12-month period 1999-2000. The study population was 123,503. The WHO definition of stroke was used. Cases were searched inside as well as outside hospital. Multiple overlapping sources and 'hot pursuit' technique were used in the process of case ascertainment.

Results: 388 cases of first-ever stroke were found, corresponding to a crude incidence rate of 314 (95% CI, 283-348) per 100,000 per year, 337 (95% CI, 294-386) for females, and 289 (95% CI, 248-336) for males. Adjusted to the European population, the corresponding rates were 254 (95% CI, 227-284) per 100,000 per year, 273 (95% CI, 238-311) for females and 232 (95% CI, 206-261) for males. The overall 28-day case-fatality rate was 19% (95% CI, 15-23). The case-fatality rates for the different subtypes of stroke were as follows: brain infarction, 10%; intracerebral haemorrhage, 20%; subarachnoidal haemorrhage 45%, and undetermined pathological type 56%.

Conclusions: The present study as well as other studies in northern and middle Scandinavia show significantly higher incidence rates than studies from other regions. The crude incidence rate, reflecting the age distribution of the population, is even higher, indicating a burden to the community that is rather increasing than decreasing.