Is mortality increased in mildly cognitively impaired individuals? A systematic literature review.

Numerous studies have focused on the effect of mild cognitive impairment in elderly people. However, the impact of mild cognitive impairment on mortality has rarely been considered so far. This paper reviews recent work on mild cognitive impairment and its mortality risk. Relevant articles were identified by a systematic search of the literature published since 1990 using the databases PubMed, Web of Science and PSYNDEXplus, bibliographies of articles identified and of earlier reviews. Those studies were considered which predominantly included persons aged 65 and over and which relied on population-based samples. Thus only eight studies could be identified. In general, the relative risk (RR) for subjects with mild cognitive impairment according to different concepts in comparison to non-affected persons varies from 1.0 to 1.9. However, only few studies are available, and a comparison of the literature is problematic, due to variations in criteria and methodology.