Projecting the Number of Elderly with Cognitive Impairment in China Using a Multi-State Dynamic Population Model

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China is aging rapidly, and the number of Chinese elderly with dementia is expected to rise. This paper projects, up to year 2060, the number of Chinese elderly within four distinct cognitive states. A multi-state population model was developed using system dynamics and parametrized with age–gender-specific transition rates (between intact, mild, moderate and severe cognitive impairment and death) estimated from two waves (2012 and 2014) of a community-based cohort of elderly in China aged ≥65 years (N = 1824). Probabilistic sensitivity analysis and the bootstrap method was used to obtain the 95% confidence interval of the transition rates. The number of elderly with any degree of cognitive impairment increases; with severe cognitive impairment increasing the most, at 698%. Among elderly with cognitive impairment, the proportion of very old elderly (age ≥ 80) is expected to rise from 53% to 78% by 2060. This will affect the demand for social and health services China. Copyright © 2017 System Dynamics Society.





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Ansah, JP, V Koh, CT Chiu, CL Chei, Y Zeng, ZX Yin, XM Shi, DB Matchar, et al. (2017). Projecting the Number of Elderly with Cognitive Impairment in China Using a Multi-State Dynamic Population Model. System Dynamics Review, 33(2). pp. 89–111. 10.1002/sdr.1581 Retrieved from

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Yi Zeng

Professor in Medicine

(1) Socioeconomic, behavior, environmental and genetic determinants of healthy aging and healthy longevity;
(2) Factors related to elderly disability and mental health;
(3) Methods of family households and elderly living arrangements forecasting/analysis and their applications in health services and socioeconomic planning, and market studies;
(4) Policy analysis in population aging, social welfare, retirement, and fertility transitions.


David Bruce Matchar

Professor of Medicine

My research relates to clinical practice improvement - from the development of clinical policies to their implementation in real world clinical settings. Most recently my major content focus has been cerebrovascular disease. Other major clinical areas in which I work include the range of disabling neurological conditions, cardiovascular disease, and cancer prevention.
Notable features of my work are: (1) reliance on analytic strategies such as meta-analysis, simulation, decision analysis and cost-effectiveness analysis; (2) a balancing of methodological rigor the needs of medical professionals; and (3) dependence on interdisciplinary groups of experts.
This approach is best illustrated by the Stroke Prevention Patient Outcome Research Team (PORT), for which I served as principal investigator. Funded by the AHCPR, the PORT involved 35 investigators at 13 institutions. The Stroke PORT has been highly productive and has led to a stroke prevention project funded as a public/private partnership by the AHCPR and DuPont Pharma, the Managing Anticoagulation Services Trial (MAST). MAST is a practice improvement trial in 6 managed care organizations, focussing on optimizing anticoagulation for individuals with atrial fibrillation.
I serve as consultant in the general area of analytic strategies for clinical policy development, as well as for specific projects related to stroke (e.g., acute stroke treatment, management of atrial fibrillation, and use of carotid endarterectomy.) I have worked with AHCPR (now AHRQ), ACP, AHA, AAN, Robert Wood Johnson Foundation, NSA, WHO, and several pharmaceutical companies.
Key Words: clinical policy, disease management, stroke, decision analysis, clinical guidelines

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