Development of a core outcome set for clinical trials of interventions to improve sleep in people with cognitive impairment

Abstract Background Although sleep disturbance is common among people with cognitive impairment, leading to negative outcomes, there is a paucity of evidence to inform management in this cohort. Existing clinical trials are marked by wide heterogeneity, both in the methods used to measure sleep and in the outcome measures reported, limiting data synthesis. A core outcome set (COS) would improve the coherence and reliability of data in future clinical trials. Methods A multi-stage mixed-methods approach was adopted in accordance with The Core Outcome Set-STAndards for Development: the COS-STAD recommendations. Results A systematic review identified 287 sleep outcome measures from previous clinical trials. Qualitative interviews revealed that people living with cognitive impairment and their caregivers are most concerned with improving overall sleep quality, reducing the time taken to fall asleep and night-time awakenings, and avoiding daytime sleepiness. Ultimately, a modified Delphi process, involving 41 experts in sleep and cognition from six different continents, selected nine outcome measures for the COS: total sleep time, sleep onset latency, wakefulness after sleep onset, number of night-time awakenings, sleep efficiency, and measures of subjective sleep quality, daytime sleepiness, cognition, and mood. The Delphi panel recommended that both subjective and objective measures be used to measure sleep outcomes over at least one week. Subjective sleep quality should be measured using a single Likert-type question. Acknowledging limitations, the Epworth Sleepiness Scale was recommended to measure daytime sleepiness, the Montreal Cognitive Assessment to monitor cognition and the Geriatric Depression Scale to assess mood. Conclusion This COS will support the conduct of future clinical trials of interventions to improve sleep in people with cognitive impairment by ensuring more reliable, comparable and coherent data. This will lead to a more robust evidence base to manage sleep disturbance and improve the care of people living with cognitive impairment.