Co-Morbid Insomnia and Sleep Apnea and Obstructive Sleep Apnea: Comparative Analysis of Clinical and Polysomnographic Features

Objectives: This study aimed to investigate and compare the clinical characteristics of obstructive sleep apnea (OSA) and co-morbid insomnia and sleep apnea (COMISA) using sleep questionnaires and polysomnographic findings. Methods: We enrolled 850 patients who completed sleep questionnaires and underwent level 1 polysomnography (PSG) with an apnea-hypopnea index (AHI) ≥15. Patients were classified as OSA if the Insomnia Severity Index (ISI) <15, or as COMISA if ISI ≥15. Demographic and clinical characteristics, as well as PSG parameters, were compared between the groups. Results: The COMISA group showed greater daytime sleepiness, lower sleep quality with increased sleep fragmentation, and longer sleep latency than the OSA group, as measured by the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index, and PSG (p<0.05). The OSA group reported more frequent snoring and more severe sleep apnea, with a higher AHI than the COMISA group (p<0.05). The COMISA group underestimated their sleep quality, while the OSA group had less insight into sleep problems. Conclusions: Patients with COMISA and OSA have different subjective and objective sleep profiles and perceptions of sleep. Understanding each characteristic and properly differentiating between COMISA and OSA in the clinic for tailored management is needed.