- Design
- Randomised trial with blinded outcome assessment
- Population
- 88 adults with co-morbid insomnia and OSA, China
- Primary outcome
- Insomnia Severity Index and PSQI at 6 weeks and 3 months
- Effect
- ISI −9.5 vs −4.0 (d −1.18); PSQI −4.9 vs −1.8; AHI −6.0 vs +2.0 events/h
Co-morbid insomnia and obstructive sleep apnoea (COMISA) is common, and insomnia often undermines CPAP use. This Chinese trial randomised 88 patients with COMISA to six weekly sessions of clinician-guided digital CBT for insomnia — sleep restriction, stimulus control, cognitive restructuring and relapse prevention — or sleep hygiene education. Outcome assessors were blinded.
At three months, insomnia severity improved by 9.5 points with CBT-I against 4.0 with sleep hygiene, and sleep quality and daytime sleepiness also improved more. After treatment, the apnoea–hypopnoea index on attended polysomnography fell by 6 events per hour with CBT-I and rose by 2 with sleep hygiene. Sleepiness rose briefly during weeks 2–4, as expected with sleep restriction, without adverse events.
The concern that sleep restriction is unsafe in OSA has kept many patients from CBT-I. This small trial suggests a guided digital format is effective and tolerable. CPAP should continue where indicated.
- Screen patients with OSA for insomnia, especially those struggling with CPAP.
- Offer CBT-I, including guided digital formats, rather than sleep hygiene advice alone.
- Warn patients that sleepiness may rise briefly during sleep restriction, and advise caution with driving in those weeks.
- Continue CPAP or other OSA treatment alongside CBT-I.
Why it matters
It addresses the fear that CBT-I is unsafe in sleep apnoea, which has kept many patients from effective insomnia treatment.
Don't overread it
With 88 patients and three months' follow-up, the reduction in apnoea severity is a secondary finding that needs confirmation.
The statistics, in plain English
An effect size (d) of −1.18 on insomnia severity is large. The apnoea–hypopnoea index change was a secondary outcome measured only after treatment, so it is less certain.
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