Predictors of mortality in patients diagnosed with probable Alzheimer's disease

OBJECTIVE: We sought to identify factors associated with mortality in persons recently diagnosed with probable Alzheimer's disease (AD). BACKGROUND: Predicting mortality in AD in needed both in patient care and public health planning. Previous studies have identified several factors which contribute to mortality in AD, but few longitudinal studies of population-based cohorts exist. METHODS: In a longitudinal follow-up study 327 patients with newly diagnosed probable AD (mean Mini-Mental State Examination MMSE score of 20) from a large, stable health maintenance organization were identified. Demographic characteristics, dementia severity, and comorbid conditions were identified at enrollment. Patients were followed longitudinally (median 3.3 years, total 898 person-years). Baseline characteristics were used to predict survival in univariate and multivariate models. RESULTS: Increased mortality was seen in patients with probable AD (9.0 deaths per 100 person-years) compared with the community population adjusted for age and gender (4.3 deaths per 100 person-years). On univariate analysis we found increased age, male gender, impairment on MMSE or Blessed dementia rating scale (DRS), rate of MMSE decline, wandering or agitation, vascular disease, and sensory impairment affecting the ability to read or hear to be moderately associated with decreased survival. After adjusting for age and gender in a multivariate model, Blessed DRS score and sensory impairment affecting the ability to read were independently associated with decreased survival. CONCLUSIONS: Short-term mortality is increased in patients newly diagnosed with probable AD. Measures of dementia severity, measures of general debility, and vascular disease are associated with increased mortality. Of these, general debility and sensory impairment were more strongly associated with shortened survival.