Impact of Cognitive Frailty on Activities of Daily Living, Cognitive Function, and Conversion to Dementia Among Memory Clinic Patients with Mild Cognitive Impairment

Article type: Research Article

Authors: Sugimoto, Taiki^{a; b; c} | Ono, Rei^c | Kimura, Ai^{a; b; d} | Saji, Naoki^a | Niida, Shumpei^b | Sakai, Toshihiro^e | Rakugi, Hiromi^f | Toba, Kenji^a | Sakurai, Takashi^{a; d; *}

Affiliations: [a] Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, Obu, Japan | [b] Medical Genome Center, National Center for Geriatrics and Gerontology, Obu, Japan | [c] Department of Public Health, Kobe University Graduate School of Health Sciences, Kobe, Japan | [d] Department of Cognition and Behavior Science, Nagoya University Graduate School of Medicine, Nagoya, Japan | [e] Shinmachi Sakai Clinic, Minoh, Japan | [f] Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Suita, Japan

Correspondence: [*] Correspondence to: Takashi Sakurai, MD, PhD, Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, 7-430 Morioka, Obu, Aichi, 474-8511, Japan. Tel.: +81 562 46 2311; Fax: +81 562 46 8394; E-mail: tsakurai@ncgg.go.jp.

Abstract: Background:Very few studies have investigated the impact of cognitive frailty in clinical settings, especially in memory clinic populations. Objective:To examine the impact of cognitive frailty on activities of daily living (ADL), cognitive function, and conversion to dementia among memory clinic patients with mild cognitive impairment (MCI). Methods:The subjects of this retrospective study were 248 MCI patients (mean age, 76.3±5.4 years; females, 60.9%). All subjects completed a comprehensive geriatric assessment at baseline and at least one assessment during 3-year follow-up. Frailty was defined by generating a frailty index (FI), and MCI patients with frailty (FI≥0.25) were considered to represent cognitive frailty. As primary outcomes, the Barthel Index, Mini-Mental State Examination, and incident dementia were evaluated during follow-up. At baseline, patients were assessed for apolipoprotein E (APOE) phenotype. A linear mixed model, as well as a Cox proportional hazards regression model with adjustment for confounding variables, was performed. Results:Of these patients, 75 (30.2%) were classified as cognitive frail. APOE ɛ4 carriers accounted for 26.7% of those with cognitive frailty and 44.5% of those without (p = 0.008). Cognitive frail patients showed a faster ADL decline (estimate, –1.04; standard error, 0.38; p = 0.007) than patients without cognitive frailty. Cognitive frailty was not associated with cognitive decline and incident dementia. Conclusion:Our findings demonstrated cognitive frailty increases the risk of dependence but not cognitive outcomes. Cognitive frailty may have heterogeneous conditions, including APOE ɛ4-related pathologies, which may affect the cognitive trajectories of patients with MCI.

Keywords: Cognitive frailty, disability, frailty, memory clinic, mild cognitive impairment, older persons

DOI: 10.3233/JAD-191135

Journal: Journal of Alzheimer's Disease, vol. 76, no. 3, pp. 895-903, 2020