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

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. APOEɛ4 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 APOEɛ4-related pathologies, which may affect the cognitive trajectories of patients with MCI.