Dementia is a major predictor of death among the Italian elderly. ILSA Working Group. Italian Longitudinal Study on Aging

Abstract

Background: Neurologic diseases are rarely listed on death certificates because death is more often attributed to cardiovascular and pneumonic events occurring during terminal stages.

Objective: To evaluate the effect of major age-associated neurologic and non-neurologic diseases on survival in a cohort of Italian elderly.

Methods: A population-based multicenter survey, carried out in eight Italian municipalities, with a sample of 5,632 individuals aged 65 to 84 years. The entire sample was screened for all the diseases under study, and all individuals were interviewed about risk factors. Those who screened positive underwent clinical assessments by specialists. Two years after the baseline survey, the study population was followed up to determine the vital status either directly from the individuals or from proxy respondents. A copy of the death certificate was obtained for each individual who had died. The risk of dying (mortality risk ratio [MRR]) was calculated using the Cox proportional hazards model in which we included all the diseases under study, age, gender, and years of education.

Results: At follow-up (mean duration 26.7 +/- 5.4 months) 444 individuals had died. The Cox proportional hazards model selected the following as significant predictors of death: age (for year of age MRR = 1.12; 95% confidence interval [CI], 1.08 to 1.15), male gender (MRR = 1.72; 95% CI, 1.27 to 2.34), institutionalization (MRR = 4.17; 95% CI, 2.20 to 7.94), dementia (MRR = 3.61; 95% CI, 2.55 to 5.11), neoplasm (MRR = 2.01; 95% CI, 1.20 to 3.38), heart failure (MRR = 1.87; 95% CI, 1.27 to 2.76), and diabetes (MRR = 1.62; 95% CI, 1.12 to 2.34).

Conclusions: These data provide further evidence on the malignancy of dementia, which proved the major predictor of death in the elderly, with an MRR higher than neoplastic diseases and other severe age-associated conditions.