Association between frailty and incident risk of disability in community-dwelling elder people: evidence from a meta-analysis

Objective: Frailty is considered to be one of the risk factors of disability. However, the results of original reported studies are not consistent with respect to the frailty and incidence of disability, and previously published meta-analyses have also shown inconsistent results. This meta-analysis was conducted to investigate the relationship between the different stages of frailty and the incidence of disability by examining updated overall trends in community-dwelling elders.

Study design: Cohort studies in English or Chinese based on associations between frailty and incident disability risks that were published from 2000 until the current date were researched using PubMed, Embase, Web of Science, and CENTRAL databases.

Methods: The Q test and I² statistic were used to examine between-study heterogeneity. Random-effect models were adopted to synthesize the results based on the study heterogeneity. Subgroup analyses were also conducted to explore the possible sources of between-study heterogeneity based on the characteristics of participants.

Results: Eighteen cohort studies with 88,906 participants were included in our meta-analyses. Compared with the non-frailty category, the combined relative risks (RRs) (95% confidence interval [CI]) of the disability were 1.66 (1.49-1.85) and 2.53 (2.01-3.14) for the category of prefrailty and frailty, respectively. Results suggested that the incident risk of disability at follow-up times <5 (RR = 3.19, 95% CI = 2.25-4.53) was significantly higher than for follow-up times ≥5 in the frailty category (RR = 2.00, 95% CI = 1.55-2.56). The risk in a sample size of ≥1000 (RR = 2.78, 95% CI = 2.04-3.14) was significantly higher than that when the sample size was <1000 (RR = 1.91, 95% CI = 1.53-2.37) in the frailty group. Compared with a value adjusted for comorbidity, the unadjusted comorbidity was significantly higher in the prefrailty category (1.90 vs. 1.52). Compared with a value adjusted for education, the unadjusted education was significantly higher in the prefrailty category (1.81 vs. 1.46). No publication bias was observed.

Conclusion: The overall meta-analysis confirms that frailty has significantly increased the incident risk of disability. Frail, elderly people are at the highest risk of future disability and may be adequate candidates for taking part in prevention and intervention programs.