Prospective community-based study of stroke in Northern Portugal: incidence and case fatality in rural and urban populations

Background and Purpose— Mortality statistics indicate that Portugal has the highest stroke mortality in Western Europe. Data on stroke incidence in Northern Portugal, the region with the highest mortality, are lacking. This study was designed to determine stroke incidence and case fatality in rural and urban populations in Northern Portugal. Methods— All suspected first-ever-in-a-lifetime strokes occurring between October 1998 and September 2000 in 37 290 residents in rural municipalities and 86 023 living in the city of Porto were entered in a population-based registry. Standard definitions and comprehensive sources of information were used for identification of patients who were followed-up at 3 and 12 months after onset of symptoms. Results— During a 24-month period, 688 patients with a first-ever stroke were registered, 226 in rural and 462 in urban areas. The crude annual incidence was 3.05 (95% CI, 2.65 to 3.44) and 2.69 per 1000 (95% CI, 2.44 to 2.93) for rural and urban populations, respectively; the corresponding rates adjusted to the European standard population were 2.02 (95% CI, 1.69 to 2.34) and 1.73 (95% CI, 1.53 to 1.92). Age-specific incidence followed different patterns in rural and urban populations, reaching major discrepancy for those 75 to 84 years old, 20.2 (95% CI, 16.1 to 25.0) and 10.9 (95% CI, 9.0 to 12.8), respectively. Case fatality at 28 days was 14.6% (95% CI, 10.2 to 19.3) in rural and 16.9% (95% CI, 13.7 to 20.6) in urban areas. Conclusions— Stroke incidence in rural and urban Northern Portugal is high compared to that reported in other Western Europe regions. The high official mortality in our country, which could be explained by a relatively high incidence, was not because of a high case fatality rate.