Mortality from dementia in a community-dwelling Brazilian population

The influence of dementia on mortality has not yet been reported for a Latin American country.

To evaluate the influence of dementia on mortality of a community-dwelling elderly population in Brazil, and to verify the extent to which the diagnosis of dementia is reported on death certificates.

A cohort of 1,656 individuals, aged 65 and over, was screened for dementia at their domiciles, in 1997. The same population was re-evaluated in 2000, and information on deaths was obtained from relatives and from the municipal obituary service. Kaplan-Meier curves were used for the survival analysis, and the mortality risk ratio (MMR) was calculated using Cox proportional hazards models.

We obtained data from 1,393 subjects, corresponding to 84.1% of the target population. The number of deaths was 58 (51.3%) among the patients with dementia and 163 (12.7%) among those without dementia in 1997 (p <0.0001). Dementia and Alzheimer's disease (AD) decreased survival, with hazards ratios of 5.16 [95% Confidence Interval (CI): 3.74-7.12] for dementia and 4.76 (95% CI: 3.16-7.18) for AD. The Cox proportional hazards model identified dementia (MMR=3.92, 95% CI: 2.80-5.48) as the most significant predictor of death, followed by age, history of stroke, complaints of visual impairment and heart failure and by severe arterial hypertension in the baseline evaluation. Dementia and/or AD were mentioned in only 12.5% of the death certificates of individuals with dementia.

Dementia causes a significant decrease in survival, and the diagnosis of dementia is rarely reported on death certificates in Brazil.