Association between insomnia and frailty in older population: A meta-analytic evaluation of the observational studies

IntroductionPoor sleep quality has been suggested as a risk factor of frailty. However, previous studies that evaluated the association between insomnia and frailty in older population showed inconsistent results. We performed a meta-analysis to comprehensively evaluate the association. MethodsObservational studies related to the aim of the meta-analysis were identified by search of PubMed, Embase, and Web of Science databases. A random-effect model incorporating the potential between-study heterogeneity was used to pool the results. ResultsTwelve studies including 16,895 old people contributed to the meta-analysis. Pooled results suggested a significant association between insomnia and frailty in the older population (odds ratio [OR]: 1.95, 95% confidence interval [CI]: 1.52-2.41, p < .001; I-2 = 80%). Subgroup analyses showed consistent association between different symptoms of insomnia and frailty, including difficulty in falling asleep (OR: 1.45), difficulty in maintaining sleep (OR: 1.23), early morning awakening (OR: 1.21), and non-restorative sleep (OR: 1.84, p for subgroup difference = .15). Results were also consistent for subgroup analyses according to the study country, sample size, cutoffs of age for defining the older population, proportions of men, diagnostic criteria for frailty, adjustment of depression, and scores of study quality (p for subgroup difference all > .05). However, a stronger association was observed for insomnia detected with the Athens Insomnia Scale (OR: 2.92) than that with Pittsburgh Sleep Quality Index (OR: 1.30) or self-reporting (OR: 1.60, p for subgroup difference = .002). ConclusionInsomnia is independently associated with frailty in the older population.