Symptoms of Insomnia among Patients with Obstructive Sleep Apnea Before and After Two Years of Positive Airway Pressure Treatment

Study Objectives: To assess the changes of insomnia symptoms among patients with obstructive sleep apnea (OSA) from starting treatment with positive airway pressure (PAP) to a 2-y follow-up. Design: Longitudinal cohort study. Setting: Landspitali-The National University Hospital of Iceland. Participants: There were 705 adults with OSA who were assessed prior to and 2 y after starting PAP treatment. Intervention: PAP treatment for OSA. Measurements and Results: All patients underwent a medical examination along with a type 3 sleep study and answered questionnaires on health and sleep before and 2 y after starting PAP treatment. The change in prevalence of insomnia symptoms by subtype was assessed by questionnaire and compared between individuals who were using or not using PAP at follow-up. Symptoms of middle insomnia were most common at baseline and improved significantly among patients using PAP (from 59.4% to 30.7%, P < 0.001). Symptoms of initial insomnia tended to persist regardless of PAP treatment, and symptoms of late insomnia were more likely to improve among patients not using PAP. Patients with symptoms of initial and late insomnia at baseline were less likely to adhere to PAP (odds ratio [OR] 0.56, P = 0.007, and OR 0.53, P < 0.001, respectively). Conclusion: Positive airway pressure treatment significantly reduced symptoms of middle insomnia. Symptoms of initial and late insomnia, however, tended to persist regardless of positive airway pressure treatment and had a negative effect on adherence. Targeted treatment for insomnia may be beneficial for patients with obstructive sleep apnea comorbid with insomnia and has the potential to positively affect adherence to positive airway pressure.