Memory impairment in a simple recall task increases mortality at 10 years in non-demented elderly

Objective: To evaluate whether memory impairment detected in the three-word delayed recall task of the Mini-Mental State Examination (MMSE) increases the risk of mortality.

Methods: The NEDICES (Neurological Diseases in Central Spain) cohort study, is a population census-based study, aimed at detecting age-associated neurological diseases in people aged 65 and over, living in one rural and two urban communities in central Spain. Participants with dementia or without MMSE evaluation at baseline were excluded. Mortality was evaluated 10.67 years after enrollment. Cox's proportional hazards regression models were used to evaluate the hazard of death according to performance in the three-word delayed recall task included in the MMSE (score 0-3), adjusting for potential covariates (sex, age, level of education, and comorbidity). Survival was estimated using Kaplan-Meier method.

Results: The final study population comprised 3778 non-demented elderly subjects. After adjusting for confounding covariates, mortality was 52% greater in persons with the lowest memory score (0) vs. persons with the highest score (3). Hazard ratios (HR) showed a tendency to an increase in mortality from the highest to the lowest memory score, which was statistically significant for the groups with none (HR=1.52; CI=1.27-1.80) or one (HR=1.24; CI=1.04-1.48) word recall. Older age, male sex, and comorbidity were also associated with mortality, but level of education was not.

Conclusions: Memory impairment in the three-word delayed free recall, a very simple task used by physicians worldwide, increases the risk of mortality at 10 years in non-demented elderly.