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December 1994

Factors Affecting Course and Survival in Alzheimer's Disease: A 9-Year Longitudinal Study

Author Affiliations

From the Department of Neurological and Psychiatric Sciences, University of Florence (Drs Bracco, Lippi, and Amaducci); the Department of Biostatistics and Epidemiology, FIDIA, Abano Terme, Padua (Drs Gallato and Grigoletto); the Department of Neurology, University of Bari (Dr Lepore); the Department of Neurology, University of Genoa (Dr Bino); the Department of Neurology, University of L'Aquila (Dr Lazzaro); the Neurological Institute "C. Besta," Milan (Drs Caretta and Piccolo); the Department of Neurological and Psychiatric Sciences, University "La Sapienza," Rome (Dr Pozzi Hi); and the Department of Neurology, University of Padua (Dr Giometto), Italy.

Arch Neurol. 1994;51(12):1213-1219. doi:10.1001/archneur.1994.00540240057016

Objective:  To evaluate mean survival and to identify prognostic factors in a cohort of patients with Alzheimer's disease (AD).

Design:  Multicentric 9-year cohort analytic study.

Setting:  Seven neurology departments throughout Italy between April 1982 and January 1984.

Patients:  We recruited a consecutive sample of 145 patients affected by probable AD (Multicenter Italian Study on Dementia protocol, National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria). Five were misdiagnosed, and 21 could not participate in the longitudinal study. The clinicodemographic characteristics of the 119 enrolled patients (49 men, 70 women; mean age, 64.7 years; SD, 4.1 years; mean duration of disease, 3.1 years; SD, 1.8 years) did not differ from those of the 26 excluded patients. All underwent extensive cliniconeuropsychological testing every 6 months for at least 2 years until the patient died or our survey ended (April 30, 1991). Mean follow-up was 5.1 years (SD, 2.5 years).

Main Outcome Measures:  Death, severe functional impairment (a score > 17 on the Blessed Dementia Scale), and severe cognitive impairment (a score of ^7 on the Information-Memory-Concentration Test).

Results:  Survival curves obtained by the Kaplan-Meier method indicated that (1) patients with early- and lateonset disease (ie, before or after age 65 years) showed no difference either in relative survival or in time to reach predetermined functional and cognitive end points; (2) severely aphasie patients became profoundly demented significantly sooner than those with mild to moderate aphasia (P<.0001). Among clinicodemographic variables analyzed by a Cox model, severe language disability and functional loss proved to be the best predictors of death independent of age at onset or degree of dementia.

Conclusions:  Age at onset did not influence course and survival in AD. Severe aphasia appears to be the best predictor of death and unfavorable course.