Stroke mortality and case-fatality rates in three geographic areas of Finland from 1983 to 1986.

BACKGROUND AND PURPOSE

Our aim was to describe the mortality and early case-fatality rates of stroke in three geographic areas of Finland during 1983 to 1986 by means of a community-based stroke register and to estimate the accuracy of registration of stroke deaths in the official statistics compared with the FINMONICA stroke register.

METHODS

Annual and average mortality and case-fatality rates of stroke were derived from data collected in the FINMONICA stroke register during 1983 to 1986. Age-specific and age-standardized rates were calculated for the three areas, and the results were compared with the official mortality statistics and with the case-fatality figures published previously in the literature for Finland and elsewhere.

RESULTS

Mortality from stroke in the three FINMONICA areas was between 73 and 90 per 100,000 per year among men aged 25 to 74 years and between 42 and 55 per 100,000 per year among women in the same age group. Average case-fatality was similar in the three areas and globally high: 20% to 27% in men and 24% to 28% in women. Approximately half of the fatal strokes occurred within less than 2 days from the onset of the attack, and a further 25% within the first week. Hemorrhagic strokes accounted for 54% to 81% of all fatal strokes occurring in less than 2 days among men, while among women the corresponding proportions varied in the three areas between 35% and 74%. Of cerebral infarctions, approximately 28% to 37% among men and 19% to 20% among women were fatal within less than 2 days. Although the number of fatal strokes was similar in both the FINMONICA register and official mortality statistics, only 82% to 85% of the stroke cases were common in both registers; a further 13% to 14% of the cases classified as stroke deaths in the FINMONICA register could also be found in the official mortality statistics, but the underlying cause of death was something other than stroke.

CONCLUSIONS

The reliability of the Finnish official mortality statistics with regard to stroke deaths is reasonably good in aggregate numbers, but at the individual level considerable discrepancies seem to occur. Mortality from stroke in Finland has not declined further after 1979 and remains high internationally. Early case-fatality of stroke also seems higher in Finland than in most other countries. We believe that both the high incidence of stroke and the severity of the attacks are contributing to mortality and case-fatality rates of stroke in Finland.