[Epidemiology of stroke in the elderly]

Abstract

Background: In the industrialized countries the very old stroke patient is more frequent than before. For the time being Japanese people have the highest expected lifespan, so the epidemiological features of stroke in the very old can be examined here quite easily. From a few publications with low case number it is known that in this group of patients the statistical characteristics of stroke is remarkably different from the younger ones.

Subjects and methods: The subjects aged 85 or more years were selected from the Akita Stroke Registry with first-ever acute stroke from 1996 to 1998.

Results: 8046 cases were recorded. There were 7362 patients aged <85 years, and 684 patients aged > or =85 years (8.5%). Sex ratio (women/men) was 1.89 in the two age groups. In the population of Akita the crude incidence of first-ever stroke was 222/100,000/year, and 1085/100,000/year in the very old, who were characterized with relatively lower prevalence of stroke risk factors, except that of atrial fibrillation (26.9%) and cardiac diseases (34.2%). The stroke subtype distribution (cerebral infarction 73.2%, intracerebral haemorrhage 20.6%, subarachnoidal haemorrhage 6.1%) was significantly different from the one known in Japan. Mortality rates were considerably high, especially in the SAH group. The most powerful prognostic factor of death was the level of consciousness at the onset. The next in the order of predicting value was the SAH subtype.

Conclusion: While people aged 85 years or more had relatively lower prevalence of cardiovascular risk factors, they suffered stroke with very high frequency, the evolved cerebrovascular event caused very severe symptoms and led to death with high rate. Implicitly this is illuminating the complexity of aging as a process, furthermore it increases the importance of prevention, and even more of the care and rehabilitation of acute stroke in this old age group.