Secular Trends of Stroke Epidemiology in Örebro, Sweden, 2017 Compared to the Trends in 1999: A Population-Based Study

BACKGROUND AND PURPOSE: A stroke incidence study in -Örebro, situated in Southern Sweden, that was carried out in 1999 showed high incidence rates. Since then, in many Western countries, declining incidence rates have been observed. The main purpose of this study is to examine whether there have been any changes in stroke incidence in the city of -Örebro between 1999 and 2017. Secondary purposes are to show trends in stroke severity, length of stay and case fatality (CF). METHODS: The criterion of an "ideal" stroke incidence study was used in both the 1999 and the present investigation. These criteria include uniform diagnostics, case ascertainment including strokes managed outside the hospital, and the use of several overlapping sources, prospective design, well-defined denominator, and a large population. RESULTS: The overall stroke incidence rate of first ever stroke (adjusted to the 2013 European population) dropped from 346/100,000 (95% CI 314-380) to 168/100,000 (95% CI 148-190). Stroke severity declined from a median of 6 to 4 points on the National Institute of Health Stroke scale. CF within 28 days also declined from 19 to 16% (n.s.). Median length-of-stay in hospital was 16 days in 1999, and 10 days in 2017. Twenty-one per cent of all kinds of stroke were recurrent (not included in the above results). CONCLUSIONS: During the years between 1999 and 2017, there have been reductions in stroke incidence, severity and mortality. The explanation is most likely to be found in the prevalence of risk factors and how they are treated. The use of antihypertensives and statins has increased, corresponding to lower levels of blood pressure and cholesterol in the population. The use of anticoagulants in patients with atrial fibrillation has increased. Cigarette smoking has decreased. These are encouraging results that show that preventive medication and public health measures work in practice.