Sleep Behaviour in Sickle Cell Disease: A Systematic Review and Meta-Analysis

Background/Objectives: There is a high prevalence of sleep behaviour disorders, as well as sleep disordered breathing (SDB), in individuals living with sickle cell disease (SCD). SDB has been systematically reviewed; therefore, this systematic review and meta-analysis focused on sleep behaviour. Methods: The comprehensive literature search, following PRISMA reporting guidelines, included all languages, conference proceedings and published theses from inception through February 2022. We identified 31 studies, with most of the research being conducted in North America, using polysomnography, actigraphy and questionnaires/diaries in paediatric SCD cohorts. Results: Total sleep time (TST) decreased, while sleep onset latency (SOL) increased with age. TST was higher on self-reported sleep diary measures and lower on polysomnography (PSG) and actigraphy assessments. SOL was lowest during PSG and highest in actigraphy. The discrepancy between sleep measures might be due to the overestimation of sleep behaviour by parents. In six studies, TST and SOL were compared between people living with SCD and healthy controls; in four, TST was longer in those living with SCD while it was shorter in two. Meta-analyses on the effect of TST and SOL were limited due to publication bias, with heterogeneity between the studies, in part related to measurement differences. No significant differences were found. Conclusions: The scarcity of case-control studies and significant heterogeneity in findings likely attributable to variations in sleep assessment methodologies. Gaps in the literature should be addressed.