ABSTRACT
Comorbid insomnia and sleep apnoea (COMISA) is a highly prevalent and debilitating sleep disorder. Cognitive behavioural therapy for insomnia (CBTi) may be an appropriate treatment for COMISA; however, no previous study has systematically reviewed and meta-analysed literature reporting on the effect of CBTi in people with COMISA. A systematic literature search was conducted across PsychINFO and PubMed (n = 295). In all, 27 full-text records were independently reviewed by at least two authors. Forward- and backward-chain referencing, and hand-searches were used to identify additional studies. Authors of potentially eligible studies were contacted to provide COMISA subgroup data. In total, 21 studies, including 14 independent samples of 1040 participants with COMISA were included. Downs and Black quality assessments were performed. A meta-analysis including nine primary studies measuring the Insomnia Severity Index indicated that CBTi is associated with a large improvement in insomnia severity (Hedges' g = -0.89, 95% confidence interval [CI] -1.35, -0.43). Subgroup meta-analyses indicated that CBTi is effective in samples with untreated obstructive sleep apnoea (OSA) (five studies, Hedges' g = -1.19, 95% CI -1.77, -0.61) and treated OSA (four studies, Hedges' g = -0.55, 95% CI -0.75, -0.35). Publication bias was evaluated by examining the Funnel plot (Egger's regression p = 0.78). Implementation programmes are required to embed COMISA management pathways in sleep clinics worldwide that currently specialise in the management of OSA alone. Future research should investigate and refine CBTi interventions in people with COMISA, including identifying the most effective CBTi components, adaptations, and developing personalised management approaches for this highly prevalent and debilitating condition.