INTRODUCTION: Cognitive impairment and frailty are important health determinants, independently associated with increased dementia risk. In this meta-analysis we aimed to quantify the association of the co-occurrence of cognitive impairment no dementia (CIND) and physical frailty with incident dementia.
METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used when reporting this review. We performed a systematic search on PubMed, Web of Science, and Embase databases for relevant articles. Longitudinal studies enrolling individuals with both CIND and physical frailty and reporting dementia incidence were eligible. Pooled estimates were obtained through random effect models and Mantel-Haenszel weighting.
RESULTS: Out of 3684 articles, five (14302 participants) were included in the meta-analysis. In comparison to participants free from frailty and CIND, the pooled hazard ratio for dementia was 3.83 (95% confidence interval [CI]: 2.64-5.56) for isolated CIND, 1.47 (95%CI: 0.89-2.40) for isolated physical frailty, and 5.36 (95%CI: 3.26-8.81) for their co-occurrence.
DISCUSSION: The co-occurrence of cognitive impairment and physical frailty is a clinical marker of incident dementia.