Subjective Cognitive Decline Prediction of Mortality: Results from the Einstein Aging Study

Article type: Research Article

Authors: Katz, Mindy J.^{a; *} | Wang, Cuiling^b | Derby, Carol A.^{a; b} | Lipton, Richard B.^{a; b; c} | Zimmerman, Molly E.^{a; d} | Sliwinski, Martin J.^{a; e} | Rabin, Laura A.^{a; f}

Affiliations: [a] Albert Einstein College of Medicine, Saul R. Korey Department of Neurology, Bronx, NY, USA | [b] Albert Einstein College of Medicine, Department of Epidemiology & Population Health, Bronx, NY, USA | [c] Albert Einstein College of Medicine, Department of Psychiatry & Behavioral Medicine, Bronx, NY, USA | [d] Fordham University, Department of Psychology, Bronx, NY, USA | [e] Pennsylvania State University, College of Health & Human Development, Department of Human Development & Family Studies, State College, PA, USA | [f] Brooklyn College and the Graduate Center of the City University of New York, Department of Psychology, Brooklyn, NY, USA

Correspondence: [*] Correspondence to: Mindy J. Katz, Albert Einstein College of Medicine, 1125 Morris Park Avenue, Van Etten 3C12B, Bronx, NY 10461, USA. Tel.: +1 718 430 3885; E-mail: mindy.katz@einstein.yu.edu.

Abstract: Background:The relation of pre-dementia stages to mortality has not been fully explored. Previous work examining subjective cognitive decline (SCD) and mortality is limited and mixed regarding methods used and consistency of findings. Objective:To examine SCD and mortality in a longitudinal, community-based cohort, using item response theory (IRT) methodology to form a composite SCD measure. Also, to assess whether this relationship was independent of clinical cognitive status. Methods:The Einstein Aging Study is a diverse longitudinal cohort of adults aged ≥70. SCD items were extracted from baseline CERAD questionnaires and a composite score was formed using IRT methodology. A total of 1,741 participants with complete data were clinically diagnosed as cognitively normal, or as having amnestic mild cognitive impairment (aMCI), nonamnestic mild cognitive impairment (naMCI), or dementia. 645 deaths occurred over a period of 8,912 person-years of follow-up. Cox proportional hazard models predicted time to death adjusting for covariates. Results:A one standard deviation unit increase in level of SCD was associated with >20% higher risk of mortality. However, when models were adjusted for clinical cognitive status, the association was no longer significant. Both dementia and aMCI predicted mortality. Furthermore, when analyses focused only on those without cognitive impairment, SCD level did not predict mortality. Conclusions:The association of SCD with mortality may be due to the association of SCD with clinical cognitive status. Thus, SCD may be used as a community-based screen to initially identify those with cognitive impairment who may be at greatest risk for death.

Keywords: Dementia, IRT methodology, mild cognitive impairment, mortality, subjective cognitive decline

DOI: 10.3233/JAD-180335

Journal: Journal of Alzheimer's Disease, vol. 66, no. 1, pp. 239-248, 2018