Survival of Outpatients with Alzheimer-type Dementia

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Abstract
Objective: To study the clinical course of Alzeheimer-type dementia and those factors that might predict or influence the length of survival. Design: A prospective cohort study. Participants: One hundred and twenty-six patients diagnosed with Alzeheimer-type dementia were selected from among 200 consecutive outpatients evaluated for suspected dementia from 1980 to 1982. All 126 patients had at least 6 years of follow-up. Setting: All patients were initially seen as outpatients at a university hospital. Measurements and Main Results: Survival analysis was done using Kaplan-Meier estimates and the Cox proportional hazards model. The mean age at symptom onset was 73.9 years and at enrollment in the study, 77.6 years. The median survival from time of enrollment in the study was 5.3 years (range, 0.2 to 7.2+ years) and from symptom onset, 9.3 years (range, 1.8 to 16+ years). Dementia severity, as measured by the Mini-Mental State Examination (MMSE), was strongly associated with survival (P < 0.001; the median survival of patients with scores above 18 (relative risk, 2.7; 95% CI, 1.6 to 4.4). Comorbid conditions and symptom duration were not related to survival. A multivariate analysis of age at symptom onset and of historical features showed that the combination of wandering and falling (relative risk, 2.1; 9% CI, 0.9 to 5.2) and the presence of behavioral problems (relative risk, 1.4; 95% IC, 0.7 to 2.9) at the time of evaluation appeared to adversely affect survival. Conclusions: Length of survival in patients with Alzeheimer-type dementia is highly variable; severity of disease (not duration), the combination of wandering and falling, and behavioral problems are associated with shorter survival. Our findings, if confirmed, may provide prognostic information for families and professionals and suggest areas in which interventions to improve survival might be focused.