Survival following a diagnosis of Alzheimer disease.

CONTEXT Survival following a diagnosis of Alzheimer disease (AD) is important information for health planners, caregivers, patients, and their families. OBJECTIVES To estimate the duration of survival following a diagnosis of AD and to determine the effect of AD on life span. DESIGN, SETTING, AND PARTICIPANTS Follow-up of participants of the Baltimore Longitudinal Study of Aging who were older than 55 years (January 1, 1985-September 30, 1999). MAIN OUTCOME MEASURES Survival duration. RESULTS The median survival time following a diagnosis of AD depended strongly on the patient's age at diagnosis. The median survival times ranged from 8.3 years for persons diagnosed as having AD at age 65 years to 3.4 years for persons diagnosed as having AD at age 90 years. There were no significant differences between men and women in survival after having a diagnosis of AD. Diagnoses of AD at ages 65 and 90 years were associated with approximately a 67% and 39% reduction in median life span, respectively. CONCLUSIONS The effect of a diagnosis of AD on life span depends crucially on the age of the person when AD is diagnosed. Caregivers, patients, and their families could plan on a median life span as long as 7 to 10 years for patients whose conditions are diagnosed when they are in their 60s and early 70s, to only about 3 years or less for patients whose conditions are diagnosed when they are in their 90s.