Incidence and long-term prognosis of initial stroke and acute myocardial infarction in Okinawa, Japan.

Abstract

We performed a cross-sectional survey of the incidence of stroke and acute myocardial infarction (AMI) in Okinawa, Japan, with a census population of about 1.2 million. A total of 3,644 cases of first-ever stroke and 898 cases of initial AMI were detected. The age-adjusted annual incidence rate of stroke was 105 per 100,000 of the standard population of Japan based on census population taken in 1985, and that of AMI was 26 per 100,000. The case-fatality rate of stroke within 28 days of onset was 12.8%, and that of AMI was 22.2%. Of the stroke cases, 51.4% were diagnosed as brain infarctions, 38.7% as brain hemorrhages, and 9.3% as subarachnoid hemorrhages. The diagnoses of stroke subtypes were confirmed by computed tomography or magnetic resonance imaging in 98.4% of all stroke cases. The long-term prognosis of patients with stroke and AMI was studied by examining their 10-yr survival rates (follow-up rate 89.8%). The cumulative survival rate was 38.2% in brain infarction cases, 40.4% in brain hemorrhage cases, and 38.2% in AMI cases. The 50% reduction of survival had occurred at 2,880 days after onset in brain infarction cases, at 2,764 days in brain hemorrhage cases, and at 2,658 days in AMI cases. In Okinawa, the incidence rate of AMI was still considerably lower than that in the Western population, and the rate of stroke was similar to that in the Western population. The ten-year survival rates were quite similar in AMI and stroke, and both were unexpectedly high.