RESEARCH – October 2006

Stroke epidemiology studies performed in Tartu: over 30 years of experience

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Abstract

Aim of the study. Population-based studies or stroke registries including all stroke patients from a defined geographical area are needed to evaluate the rate of stroke incidence in a population. The main goal of the present study was to compare the results of three stroke registers from Tartu, Estonia, from 1970 to 2003, and to analyse trends in stroke incidence and case-fatality rates over these years.
Methods. Patients with first-ever ischemic stroke from the three registers were included in the study: 667 patients from 1970–73; 829 patients from 1991–93 and 451 patients from 2001–03. The basic methods of these registers are the same; the main difference is in
the use of computerized tomography in the diagnosis of stroke subtypes and in the age group classification for 1970–73. Therefore, main comparisons are available for two last registers.
Results. The adjusted rates of stroke incidence increased in the period 1970–1993 but declined during the last decade (from 250 to 223 per 100,000). A statistically significant decline has been observed among younger age groups. The age-adjusted incidence rate for women decreased from 204 per 100,000 in 1991 to 164 per 100,000 in 2003. In most age groups, overall case-fatality rates declined during the past decade, while the trend in the age group 75–84 years was statistically significant. During 30 years, the proportion of hospitalised stroke cases has increased substantially (from 34% to 88%) and the 28-days case-fatality rate has declined from 49% to 26%.
Conclusion. The incidence of the first ever stroke in Tartu has declined significantly during the past decade and reached the level of the first registry. The rise in incidence rates at the beginning of the 1990s can be explained by profound socioeconomic changes in the
community and the possibly higher level of stress. The 28-day case-fatality rate has declined from 49% to 26%. However, even after the decline in case-fatality and in incidence rates for those <65 years, the figures are still high in comparison with those reported in other studies. The prevalence of cardiovascular risk factors, and the incidence of stroke and ischemic heart disease has been high in Eastern European countries. Our data show that the situation has improved.