Natural Progression Model of Cognition and Physical Functioning among People with Mild Cognitive Impairment and Alzheimer's Disease

Article type: Research Article

Authors: Handels, Ron L.H.^{a; *} | Xu, Weili^b | Rizzuto, Debora^b | Caracciolo, Barbara^{b; c} | Wang, Rui^b | Winblad, Bengt^{b; d} | Verhey, Frans R.J.^a | Severens, Johan L.^e | Fratiglioni, Laura^{b; f} | Joore, Manuela A.^g | Wimo, Anders^d

Affiliations: [a] Alzheimer Centre Limburg, School for Mental Health and Neuroscience (MHeNS), University Medical Centre, Maastricht, The Netherlands | [b] Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Stockholm, Sweden | [c] Stress Research Institute, Stockholm University, Stockholm, Sweden | [d] KI-Alzheimer Disease Research Center, Karolinska Institutet, Stockholm, Sweden | [e] Institute of Health Policy and Management, Erasmus University Rotterdam, Rotterdam, The Netherlands | [f] Stockholm Gerontology Research Center, Stockholm, Sweden | [g] Maastricht University, CAPHRI School for Public Health and Primary Care, Faculty of Health Medicine and Life Sciences, Department of Health Organization, Policy and Economics, Maastricht, The Netherlands

Correspondence: [*] Correspondence to: Ron L.H. Handels, Department of Psychiatry and Neuropsychology, University Hospital of Maastricht/Alzheimer Centre Limburg, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Tel.: +31 43 3884098; Fax: +31 43 3884092; E-mail: ron.handels@maastrichtuniversity.nl.

Abstract: Background:Empirical models of the natural history of Alzheimer’s disease (AD) may help to evaluate new interventions for AD. Objective:We aimed to estimate AD-free survival time in people with mild cognitive impairment (MCI) and decline of cognitive and physical function in AD cases. Methods:Within the Kungsholmen project, 153 incident MCI and 323 incident AD cases (international criteria) were identified during 9 years of follow-up in a cognitively healthy cohort of elderly people aged ⩾75 at baseline (n = 1,082). Global cognitive function was assessed with the Mini-Mental State Examination (MMSE), and daily life function was evaluated with the Katz index of activities of daily living (ADL) at each follow-up examination. Data were analyzed using parametric survival analysis and mixed effect models. Results:Median AD-free survival time of 153 participants with incident MCI was 3.5 years. Among 323 incident AD cases, the cognitive decline was 1.84 MMSE points per year, which was significantly associated with age. Physical functioning declined by 0.38 ADL points per year and was significantly associated with age, education, and MMSE, but not with gender. Conclusion:Elderly people with MCI may develop AD in approximately 3.5 years. Both cognitive and physical function may decline gradually after AD onset. The empirical models can be used to evaluate long-term disease progression of new interventions for AD.

Keywords: Alzheimer's disease, dementia, disease progression, economic model, mild cognitive impairment

DOI: 10.3233/JAD-130296

Journal: Journal of Alzheimer's Disease, vol. 37, no. 2, pp. 357-365, 2013