Risk of death from Alzheimer's disease in a community population of older persons.

A random sample of 467 persons over age 65 years from the population of an urban US community, stratified by age, sex, and performance on a brief memory test, underwent clinical evaluation for dementing illness in 1982-1984. Of these persons, 134 had probable Alzheimer's disease, 166 had possible Alzheimer's disease, and 167 had no evidence of Alzheimer's disease. Over a median follow-up period of 4.9 years following evaluation, 165 (35%) died. Overall, persons with probable Alzheimer's disease had a relative risk of death 1.44 (95% confidence interval (Cl) 1.05-1.96) times that of the unaffected. Level of cognitive impairment and the presence of cachexia upon physical examination both strongly and independently modified risk of death. Among those with probable Alzheimer's disease, mortality for those with mild or moderate cognitive impairment and no evidence of cachexia was comparable to that of the unaffected. However, among those with probable Alzheimer's disease and either severe cognitive impairment or cachexia, the risk of death was substantially higher. Persons with probable Alzheimer's disease who had both severe cognitive impairment and clear cachexia had a risk of death 4.60 (95% Cl 1.63-13.1) times that of unaffected persons.