Dementia and disability: impact on mortality. The Italian Longitudinal Study on Aging.

Dementia is known to be associated with excess mortality. Physical disability, as a marker of dementia severity, is often considered the last step on the way from disease to death. The objective of this study was to investigate the direct effect of dementia on mortality in a population-based study, carried out in Italy, with a sample of 5,632 individuals aged 65-84 years. At 4-year follow-up, 998 participants had died. The independent predictors of death were: age (75-84 years; HR 2.63, CI = 2.11-3.27), male sex (HR 1.45, CI = 1.22-1.74), coronary heart disease (HR 1.61, CI = 1.34-1.94), moderate and severe instrumental activities of daily living disability (HR 1.98, CI = 1.30-3.03 and HR 3.26, CI = 2.09-5.09, respectively), diabetes in subjects with a survival time greater than 23 months (HR 0.68, CI = 0.43-1.08) and dementia (HR 2.07, CI = 1.62-2.66). These data provide evidence that dementia per se, independently from physical disability, is a strong predictor of death in the elderly.