Hospitalization and case-fatality rates for stroke in Canada from 1982 through 1991. The Canadian Collaborative Study...

The purpose of this study was to estimate rates of hospitalization and in-hospital case-fatality for cerebral infarction and intracerebral hemorrhage in Canada and to describe variation in rates by age, sex, and calendar period.

Data were obtained from hospitalization databases for each of Canada's 10 provinces for the 10 fiscal years of 1982 through 1991. All hospitalizations of persons 15 years of age or older with a primary diagnosis at discharge coded 431, 434, or 436 according to the International Classification of Disease, 9th Revision, were included. Rates per 100,000 population were calculated for intracerebral hemorrhage and cerebral infarction, for men and women, and for five age groups. Annual age- and sex-specific, 30-day, in-hospital case-fatality rates were also calculated.

A total of 335,283 discharges for stroke were enumerated over the 10-year period (309,631 cerebral infarctions and 25 652 intracerebral hemorrhages). A significant decline of approximately 1% per year was observed for the rate of cerebral infarctions. For hemorrhages, the reverse was seen. For men there was a 44% increase over the 10-year period, and for women there was a 34% increase. In-hospital case-fatality rates for cerebral infarctions increased with age but did not differ by sex when age was considered. For the five age groups of 15 to 54, 55 to 64, 65 to 74, 75 to 84 and > or = 85 years, rates were 6%, 8%, 12%, 18% and 27%, respectively. For intracerebral hemorrhage, the in-hospital case-fatality rates declined significantly over time from approximately 36% to 29%, 55% to 37%, 49% to 41%, 66% to 45%, and 72% to 59% for the five age groups, respectively.

The possibility that these changes are artifactual could not be ruled out, but because there is no obvious risk in assuming that they are not, it would be prudent to investigate their causes further.