Prognostic Significance of Mild Cognitive Impairment Subtypes for Dementia and Mortality: Data from the NEDICES Cohort

Article type: Research Article

Authors: Bermejo-Pareja, Félix^{a; b; *} | Contador, Israel^c | Trincado, Rocío^b | Lora, David^d | Sánchez-Ferro, Álvaro^{e; f} | Mitchell, Alex J.^g | Boycheva, Elina^d | Herrero, Alejandro^h | Hernández-Gallego, Jesús^{b; h; i} | Llamas, Sara^d | Villarejo Galende, Alberto^{b; h} | Benito-León, Julián^{b; h}

Affiliations: [a] Consultant Neurologist of the Clinical Research Unit (Imas12), University Hospital “12 de Octubre”, Madrid, Spain | [b] Ciberned, Carlos III Research Institute, Madrid, Spain | [c] Department of Basic Psychology, Psychobiology and Methodology of Behavioral Sciences, University of Salamanca, Spain | [d] Clinical Research Unit (Imas12- CIBERESP), University Hospital “12 de Octubre”, Madrid, Spain | [e] Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA | [f] Centro Integral de Neurociencias A.C., Fundación Hospitales de Madrid, Móstoles, Madrid, Spain | [g] Department of Cancer and Molecular Medicine, University of Leicester, UK | [h] Department of Neurology, University Hospital “12 de Octubre”, Madrid, Spain | [i] Department of Medicine, Complutense University (UCM), Madrid, Spain

Correspondence: [*] Correspondence to: Félix Bermejo Pareja, Unidad de Investigación, Hospital Universitario “12 de Octubre”, Avenida de Córdoba s/n, 28041 Madrid, Spain. Tel.: +34 917792767/917792644; E-mail: [email protected].

Abstract: Background:The predictive value of diverse subtypes of mild cognitive impairment (MCI) for dementia and death is highly variable. Objective:To compare the predictive value of several MCI subtypes in progression to dementia and/or mortality in the NEDICES (Neurological Disorders in Central Spain) elderly cohort. Methods:Retrospect algorithmic MCI subgroups were established in a non-dementia baseline NEDICES cohort using Spanish adaptations of the original Mini-Mental State Examination (MMSE-37) and Pfeffer’s Functional Activities Questionnaire (Pfeffer-11). The presence of MCI was defined according two cognitive criteria: using two cut-offs points on the total MMSE-37 score. Five cognitive domains were used to establish the MCI subtypes. Functional capacity (Pfeffer-11) was preserved or minimally impaired in all MCI participants. The incident dementia diagnoses were established by specialists and the mortality data obtained from Spanish official registries. Results:3,411 participants without dementia were assessed in 1994-5. The baseline prevalence of MCI varied according to the MCI definition (4.3%–31.8%). The follow-up was a mean of 3.2 years (1997-8). The dementia incidence varied between 14.9 and 71.8 per 1,000/person-years. The dementia conversion rate was increased in almost all MCI subgroups (p >  0.01), and mortality rate was raised only in four MCI subtypes. The amnestic-multi-domain MCI (aMd-MCI) had the best dementia predictive accuracy (highest positive likelihood ratio and highest clinical utility when negative). Conclusions:Those with aMd-MCI were at greatest risk of progression to dementia, as in other surveys and might be explored with increased attention in MCI research and in dementia preventive trials.

Keywords: Amnesic multidomain MCI, dementia, dementia conversion, MCI mortality, MCI subtypes, MMSE-37, NEDICES, Pfeffer’s FAQ

DOI: 10.3233/JAD-150625

Journal: Journal of Alzheimer's Disease, vol. 50, no. 3, pp. 719-731, 2016