Co-morbid Insomnia and Sleep Apnea (COMISA) in a large sample of Iranian: prevalence and associations in a sleep clinic population.

Background: Sleep apnea (SA) and insomnia (INS) are prevalent sleep disorders among referrals to sleep clinics. People with comorbid insomnia and sleep apnea (COMISA) suffer both disorders simultaneously. The epidemiology of COMISA is not well known in the Middle East including Iran. We hypothesized that COMISA is prevalent in metropolitan sleep clinic cohorts in Iran.

Method: The records of patients aged < 95 years referred to sleep disorders centers in four large metropolitan areas including Kermanshah, Tabriz, Shiraz, and Ahvaz were examined. Polysomnography (PSG) was performed in all these patients in specialized centers and the results were scored by a trained technician and interpreted by a sleep specialist. SA was defined as an Apnea-Hypopnea Index (AHI ≥ 5), INS was defined by psychiatrists according to self-report and clinical interviews, and COMISA was defined if both disorders were present. Participants with neither condition were included in as comparator group. One-way ANOVAs, correlation, and linear/logistic regression analyses were used.

Results: This study included 1807 patients (Mean age 49.3, SE ± 13.7; 38.8% Female). Comparator, INS, SA and COMISA made up 7.2%, 16%, 50.2% and 26.6% of the sample, respectively. Logistic regression analyses showed that male gender, older age, and increasing neck circumference, but not BMI, were associated with COMISA. Epworth Sleepiness Scale scores were lower in INS (5.39 ± 5.78) compared to the other three groups.

Conclusion: COMISA is a prevalent condition in metropolitan sleep centers in Iran among participants referred to sleep centers. The data showed that male gender and age were associated significantly with COMISA.