The relationship between sleep-wake disturbances and frailty among older adults: A systematic review

Aim: To examine the relationship between sleep-wake disturbances and frailty among older adults.

Design: A systematic review.

Data sources: Peer-reviewed and English-written studies were sourced in CINAHL Complete, PsycINFO, Ovid-Medline, and by hand searching from inception to December 2018.

Review methods: This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The Cochrane Collaboration Risk of Bias Tool was used to appraise the methodological quality. A quantitative meta-analysis was not conducted due to the heterogeneous effect estimates statistics and measurements of sleep-wake disturbances. Instead, a narrative synthesis was carried out conforming to the Centre for Reviews and Dissemination's guidance.

Results: Six cross-sectional studies and one longitudinal study were included in this review. There was consistent evidence on the association between perceived sleep quality and frailty among older adults; whereas the results for insomnia symptoms, excessive daytime sleepiness, and sleep-wake pattern were inconclusive.

Conclusion: Despite a comprehensive search, this review has identified limited research in this field of study. Nevertheless, this review has identified consistent evidence on the relationship between perceived sleep quality and frailty. Future rigorous research with more validated use of measurement tools are needed to explore whether insomnia symptoms, excessive daytime sleepiness, and sleep-wake pattern are related to frailty.

Impact: Due to the indefinite role of sleep-wake disturbances in the pathophysiology of frailty, nearly all nurse-led care programmes for frail older adults did not include any sleep-related screening and interventions. Nevertheless, the consistent evidence on the association between poor sleep quality and higher risk of frailty shows the need of incorporating assessments and interventions for improving sleep quality in nurse-led care programmes for frail older adults. Moreover, such evidence also generates casual hypothesis for future prospective longitudinal studies that explore the causality of this relationship.