Objectives: The study was conducted to analyze risk, causes and places of death, and related factors among elderly with and without dementia in a community.
Methods: In 1994, the entire elderly population, aged 65 and older in city K were surveyed for their health status. Among them, 201 were diagnosed as suffering from dementia by psychiatric doctors, according to DSM-III-R. Date, causes and places of death were surveyed individually using the vital statistics record of the national government, for ten years from July 1, 1994. The risk of death adjusted for age-classes, was analyzed with the Cox proportional hazard model. Median survival time was calculated using the Kaplan-Maier method, and causes and places of death were analyzed with the chi2 test. Ten factors at the baseline study were examined for each sex, to analyze their relations to death.
Results: Among 198 elderly with dementia followed, 170 died (85.9%), while 1696 (33.9%) died in the 5004 non-dementia group. The hazard ratio for dementia/non-dementia was 2.99, and the female/male was 0.56, stratified by age-classes. The rate for death due to CVD in the elderly with dementia was particularly high accounting for 37.1% of the total. With the CVD and undifferentiated types of dementia, the rate was 47.0%. The rate for malignant tumor was low. In the dementia group, mortality at nursing homes was higher and at hospitals/clinics was lower, compared to non-dementia group (p< 0.05). When stratified by age-classes, the factors significantly related to death of the elderly with dementia were severity of dementia (male), type of dementia (female), being bed-ridden and having impaired walking or toileting capabilities (both sexes).
Conclusions: Dementia is a significant death related factor for elderly people, particularly linked to mortality from cerebro-vascular disease. The type and severity of dementia, and walking or toileting activities appear significant to be factors for death of elderly with dementia.