The Effect of Digital Cognitive Behavioural Therapy for Insomnia in People With Co-Morbid Insomnia and Sleep Apnoea (COMISA): A Pilot Randomised Controlled Trial

Co-morbid insomnia and sleep apnoea (COMISA) is a prevalent and debilitating condition. Cognitive behavioural therapy for insomnia (CBTi) is an effective but largely inaccessible treatment in patients with COMISA. We aimed to test a self-guided interactive digital CBTi program tailored for COMISA and insomnia alone. A pilot randomised controlled trial was conducted to investigate the effect of an interactive tailored digital CBTi program, versus digital sleep education (control) on symptoms of insomnia, depression, anxiety, sleepiness, fatigue, and maladaptive beliefs about sleep in people with COMISA. Online questionnaires were administered at baseline, 8 weeks, 16 weeks, and 24 weeks. Intent-to-treat mixed models and complete-case Fisher's exact analyses were used. Participants were 30 adults with COMISA (Age M[sd] = 61.0[10.3], 60% female, BMI = 33.5[6.5]). Compared to control, CBTi was associated with lower insomnia (M[95% CI] difference = 8.3[5.0–11.6], p < 0.001, d = 2.88), depression (3.7[1.0–6.5], p = 0.008, d = 1.66), anxiety (2.9[0.9–4.9], p = 0.005, d = 0.62), sleepiness (2.7[0.8–4.5], p = 0.007, d = 0.71), and maladaptive beliefs about sleep (13.9[5.7–22.2], p = 0.001, d = 1.16), but not fatigue (1.9[−1.2–4.9], p = 0.229, d = 0.68) at 8-week follow-up, controlling for baseline scores. The CBTi group experienced greater rates of insomnia remission (ISI < 8; 42%, vs. 0%, p = 0.012), and improvement (ISI reduction ≥ 6; 75% vs. 14%; p = 0.004) by 8-weeks. Improvements in the CBTi group were sustained by 24-weeks. This tailored digital CBTi program led to large and sustained improvements in insomnia, depression, anxiety, sleepiness, and maladaptive beliefs about sleep in people with COMISA.