Trends in incidence, case-fatality rate, and severity of stroke in northern Sweden, 1985-1991.

Abstract

BACKGROUND AND PURPOSE--Incidence, case-fatality rate at 28 days, and severity of acute stroke were recorded for 7 years in a large population-based stroke register to understand the reasons for the decline in stroke mortality in northern Sweden. Within the framework of the World Health Organization MONICA Project, acute stroke was monitored in people aged 35 to 74 years in northern Sweden from 1985 through 1991 (target population in 1985, 238,948). The annual incidence of stroke decreased by an average of 2.3%/y in men aged 35 to 64 years (P = .074) and increased significantly by 1.1%/y in men aged 65 to 74 years (P = .041). No significant changes in incidence occurred in either age group in women. The 28-day case-fatality rate in first-ever strokes (both sexes together) declined from 21.9% to 15.4% in patients aged 65 to 74 years (P = .02). Among survivors, the proportion with extensive motor deficits (at any time during the first 28 days) declined in patients younger than 65 years as well as in those older than 65 years (P = .007 and P = .019, respectively). In patients aged 35 to 64 years, the proportion with aphasia/dysphasia also decreased significantly (P = .032), but no such trend was seen in those aged 65 to 74 years. A shift toward higher ages has been noted in the occurrence of first-ever strokes in men, while incidence has remained unchanged in women. During the 7 years of observation, stroke has become a less severe disease.