Frailty as a Predictor of Alzheimer Disease, Vascular Dementia, and All Dementia Among Community-Dwelling Older People: A Systematic Review and Meta-Analysis.

OBJECTIVE

To perform a systematic search of the literature for currently available evidence on frailty as a predictor of dementia and to conduct a meta-analysis to synthesize the pooled risk estimates among community-dwelling older people.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Embase, MEDLINE, CINAHL Plus, PsycINFO, and the Cochrane Library from 2000 to January 2016, and reference lists of relevant articles.

ELIGIBILITY CRITERIA

Any studies that prospectively examined the incident risks of dementia with frailty among community-dwelling older people without language restriction.

RESULTS

Of 2565 studies identified through the systematic review, 7 studies were included in this review. Of these, 4 studies reported hazard ratios (HR) of incident dementia for physical frailty defined by Cardiovascular Health Study criteria and were included in a meta-analysis. Frailty was a significant predictor of incident Alzheimer disease (4 studies: pooled HR = 1.28, 95% confidence interval (95% CI) = 1.00-1.63, P = .05), vascular dementia (2 studies: pooled HR 2.70, 95% CI 1.40-5.23, P = .003), and all dementia (3 studies: pooled HR 1.33, 95% CI 1.07-1.67, P = .01). Heterogeneity across the studies was low to modest (I(2) = 0%-51%). A random-effects meta-regression analysis showed that the female proportion of the cohort primarily mediated the association of frailty with Alzheimer disease (female proportion coefficient = 0.04, 95%CI = 0.01-0.08, P = .01).

CONCLUSION

This systematic review and meta-analysis suggests that frailty was a significant predictor of Alzheimer disease, vascular dementia, and all dementia among community-dwelling older people. Frail women may have a higher risk of incident Alzheimer disease than frail men.