Estimation of the Prevalence of Comorbid Insomnia with Obstructive Sleep Apnea (COMISA) in Adult Patients with Suspected Sleep-Disordered Breathing

Keywords

COMISA - OSA - chronic insomnia - sleep quality

Introduction: Obstructive sleep apnea (OSA) and insomnia are the most prevalent sleep disorders worldwide. Therefore, the association of these diseases (COMISA) is also prevalent, especially among adult patients referred for polysomnography. However, studies evaluating the prevalence of COMISA are surprisingly scarce, especially in Brazil.

Objective: To determine the prevalence of COMISA in adults with suspected sleep-disordered breathing (SDB). Secondarily, we also evaluated the impact of COMISA diagnosis on sleep quality and the frequency of excessive daytime sleepiness (EDS).

Methods: A cross-sectional study was conducted from March 2020 to July 2024. The local Ethics Committee approved the research project (#64135922.2.0000.5257). Chronic insomnia was defined as experiencing at least one of the following nocturnal symptoms: difficulty falling asleep, difficulty staying asleep, or waking up earlier than expected, on at least 3 nights per week for a minimum of 3 months. Using a home sleep apnea test, OSA diagnosis was based on the respiratory event index (REI) ≥ 5.0/h. EDS was assessed by an Epworth Sleepiness Scale score > 11 while the Ru-SATED questionnaire assessed sleep quality. Two-tailed statistical tests were performed using the chi-square (categorical variables) and the Kruskal-Wallis (continuous variables) test.

Results: The study included 255 individuals (57.3% females). Out of the 255 participants in the study, 16.9% (n = 43) had neither chronic insomnia nor OSA, 10.1% (n = 26) had chronic insomnia only, 42.4% (n = 108) had OSA only, and 30.6% (n = 78) had COMISA. There was a linear increase in the median REI values according to the 4 subgroups: controls: 3.5/h (interquartile range [IQR]: 2.7-4.1), insomnia: 3.8/h (IQR: 2.1-4.5), OSA: 10.2/h (IQR: 7.1-26.0), and COMISA: 11.4/h (IQR: 7.2-22.6); p < 0.001. The prevalence of EDS did not vary among the 4 subsamples: controls (37.2%), insomnia (46.2%), OSA (45.4%), and COMISA (53.8%); p = 0.357. Patients with chronic insomnia had the worst scores on the Ru-SATED tool: 6.0 points (IQR: 4.7-6.2), followed by COMISA: 7.0 points (5.0-8.0), OSA, and controls (both with 9.0 points [IQR: 7.0-10.0]); p < 0.001.

Conclusion: Our research revealed a high prevalence of COMISA. Individuals with COMISA had the highest REI values compared to controls, OSA, and chronic insomnia alone.The presence of COMISA did not affect the frequency of EDS. However, individuals with insomnia alone or with COMISA had poorer sleep quality.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
16 September 2025