Frailty and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis of Cross-Sectional Studies.

The relationship between cognitive function and frailty among older adults is a growing area of research due to the implications of cognitive and physical decline for functional independence in late life. Multiple studies demonstrate a meaningful relationship between these two factors, which together may constitute increased risk of negative health outcomes for older adults. The current analysis was conducted to 1) systematically review current evidence for differences in cognitive performance based on frailty status among older adults and provide quantitative evidence for the magnitude of this effect, and 2) assess the influence of demographic and methodological variables on this effect. The preregistered protocol (CRD42018087138) included a search of EBSCOhost, Pubmed, and Embase online databases and reference lists to identify cross-sectional studies comparing frail and non-frail or robust older adults (60+) on cognitive performance. In total, 42 effects were retrieved from 38 studies, expressed as Hedges' g, and pooled based on a random-effects model. Results indicated an overall significant, negative effect of frailty status on cognitive function among tests of global cognitive function (g = 0.734: 95% CI = 0.601-0.867) and individual cognitive domains (g = 0.439: 95% CI = 0.342-0.535). Age, frailty assessment used, and cognitive status of the sample did not significantly moderate the overall effect. Post-hoc moderator analysis revealed that difference in mean age of frail and robust groups significantly moderated the overall effect (R2 = 0.38, β = .0974, 95% CI = 0.0537-0.141). Implications for future research are discussed.