Transitions in cognitive status in relation to frailty in older adults: a comparison of three frailty measures.

OBJECTIVES

Cognitive decline is related to frailty. Frailty can be operationalized in different ways, which have an unknown impact on the estimation of risk. Here, we compared 3 frailty measures in relation to cognitive changes and mortality in the Canadian Study of Health and Aging (CSHA).

DESIGN

Prospective population-based study, with 5 year follow up.

PARTICIPANTS/SETTING: 2,305 subjects aged 70+ years.

METHODS

For each participant, cognitive status was measured by the errors in the Modified Mini-Mental State Examination (3MS) score. Three frailty measures were used: a Frailty Index based on the Comprehensive Geriatric Assessment (FI-CGA) evaluated from 47 potential deficits, a Clinical Frailty Score and the Fried frailty phenotype. Multivariate Poisson regression and multivariate logistic regression were used to examine the association between baseline cognitive errors and frailty and death, respectively, while controlling for possible confounders (age, sex, education, and baseline cognitive status).

RESULTS

Changes in cognitive status were strongly associated with baseline cognition and frailty, however defined. In multivariate models adjusted for age, sex and education, each frailty measure was associated with cognitive decline and with mortality. The frailest people (from the highest FI-CGA tertile) rarely showed cognitive improvement or stabilization (1.5%, 95% CI=0.002%-2.8%) compared with non-frail people (from the lowest tertile of the FI-CGA), of whom 27.8% (95% CI=24.5%-31.1%) did not deteriorate.

CONCLUSIONS

Frail elderly people have an increased risk of cognitive decline. All frailty measures allowed quantification of individual vulnerability and predict both cognitive changes and mortality.