Effect of high-risk sleep apnea on treatment-response to a tailored digital cognitive behavioral therapy for insomnia program: a quasi-experimental trial

Introduction: Therapist-delivered Cognitive Behavioral Therapy for Insomnia (CBTi) is an effective but largely inaccessible treatment for people with Co-Morbid Insomnia and Sleep Apnea (COMISA). To increase CBTi access for COMISA, we aimed to develop a self-guided interactive 5-session digital CBTi program that is appropriate for people with insomnia-alone and COMISA, and compare its effectiveness between people with insomnia-alone, vs. comorbid insomnia and high-risk sleep apnea. Methods: Data from 62 adults with insomnia symptoms were used. High-risk sleep apnea was defined as a score of ≥5 on the OSA50. Participants self-reported symptoms of insomnia (ISI), depression, anxiety, sleepiness (ESS), fatigue, and maladaptive sleep-related beliefs (DBAS-16) at baseline, 8-week, and 16-week follow-up. ESS scores were additionally assessed during each CBTi session. Intent-to-treat mixed models and complete-case chi2 analyses were used. Results: There were more participants with insomnia-alone [n = 43, age M (sd) = 51.8 (17.0), 86.1% female] than suspected COMISA [n = 19, age = 54.0 (14.8), 73.7% female]. There were no between-group differences in baseline questionnaire data, or rates of missing follow-up data. There were no significant group by time interactions on any outcomes. Main effects of time indicated moderate-to-large and sustained improvements in insomnia (d = 3.3), depression (d = 1.2), anxiety (d = 0.6), ESS (d = 0.5), fatigue (d = 1.2), and DBAS-16 symptoms (d = 1.2) at 16-weeks. ESS scores did not increase significantly during any CBTi session. Conclusion: This interactive digital CBTi program is effective in people with insomnia-alone, and people with co-morbid insomnia and high-risk sleep apnea. Further research is required to determine the effectiveness, safety and acceptability of digital CBTi in people with insomnia and confirmed sleep apnea. Clinical Trial Registration: This trial was prospectively registered on the Australian and New Zealand Clinical Trials Registry (ANZCTR, ACTRN12621001395820).