Declining mortality from subarachnoid hemorrhage - Changes in incidence and case fatality from 1985 through 2000

Background and Purpose-Northern Sweden has one of the highest incidence rates of subarachnoid hemorrhage (SAH) among the populations covered by the WHO MONICA (Monitoring of Trends and Determinants in Cardiovascular Disease) Project, approximately twice as high as in the other populations in Europe. In this study, trends in incidence, 28-day case fatality (CF), and mortality in SAH were followed over a 16-year period. Methods-Since 1985, all SAHs in northern Sweden among patients 25 to 74 years old have been validated using strict MONICA criteria. From 1985 through 2000, 392 men and 592 women had SAH. During 3 years, 1997 to 1999, SAH among those aged 75 and older were also included. Results-The total incidence among those 25 years and older was 13.3 per 100 000 in men and 24.4 per 100 000 in women. During the 16 years of observation, age standardized incidence in the group aged 25 to 74 years decreased significantly in men (P for trend <0.0001) but remained essentially unchanged in women (P for trend=0.64). The 28-day CF for all years was 36.5% in men, with no significant trend (P=0.7). In women, average CF was 35%, with a significant decline (P=0.003). The annual mortality decreased significantly in both sexes (by 3.87 [95% CI +/- 2.75 percentage points] in men and 3.97 [95% CI +/- 2.29] in women). Conclusions-The decline in SAH mortality has different explanations in men ( declining incidence) and in women (declining CF).