Clinical and Polysomnographic Characteristics of Comorbid Insomnia and Sleep Apnoea: Findings From the TURKAPNE Cohort

Insomnia symptoms are frequently reported by patients with obstructive sleep apnoea (OSA). We aimed to estimate the prevalence of co-occurring insomnia symptoms and OSA and to characterize its clinical, comorbidity and polysomnographic profile in a nationwide sleep clinic population. We analysed data from 12,715 adults enrolled in the multicentre Turkish Sleep Apnoea Database (TURKAPNE). All participants underwent full-night laboratory-based polysomnography and completed standardized symptom questionnaires. Participants were categorized into four groups: OSA with co-occurring insomnia symptoms, OSA only, insomnia symptoms only and a reference group with neither OSA nor insomnia symptoms. Multivariable logistic regression analyses were performed to evaluate symptom associations across groups. Of 12,715 participants, 8142 (64.0%) had OSA only, 3275 (25.8%) had OSA with co-occurring insomnia symptoms, 388 (3.1%) had insomnia symptoms only and 910 (7.2%) constituted the reference group. Compared with the reference group, OSA with co-occurring insomnia symptoms was strongly associated with nocturnal dyspnoea (aOR 3.94, 95% CI 3.07-5.04), morning headache (aOR 3.31, 95% CI 2.46-4.44) and depressed mood (aOR 3.01, 95% CI 2.20-4.13). Polysomnography demonstrated respiratory disturbance together with prolonged sleep latency and a higher arousal index in participants with OSA and co-occurring insomnia symptoms. To conclude, in this large national sleep clinic cohort, OSA with co-occurring insomnia symptoms was common and associated with greater clinical complexity and combined respiratory and sleep-continuity disturbances. Systematic assessment of insomnia symptoms in patients evaluated for OSA may improve clinical characterization and support more integrated management approaches. Trial Registration: NCT02784977.