(396) Severity and likelihood of chronic pain in individuals with obstructive sleep apnea and insomnia

      Short sleep duration and insomnia have been linked to higher pain and an increased risk of developing chronic pain, but relatively little research has examined the relationship of obstructive sleep apnea (OSA) to pain. This study examined the unique contributions of OSA and insomnia to chronic pain. Patients referred to an academic sleep center for overnight polysomnography were invited to participate. Participants (N = 105) completed questionnaires about their sleep and pain, including two weeks of sleep/pain diaries. Most participants (80.00%) reported chronic pain, with the most common types of pain being musculoskeletal (28.57%) and headaches (24.76%). The lower back was the most frequently reported body region with chronic pain (48.57%). The likelihood of having chronic pain did not differ by sleep disorder, χ2(3) = 4.26, p = .24. However, there was a significant difference in pain intensity, F(3, 84) = 6.00, p < .01. Bonferroni-corrected post-hoc comparisons showed that individuals with comorbid OSA/insomnia reported an average pain intensity that was 20 points (out of 100) higher than individuals with insomnia or no diagnosis and 28 points higher than those with OSA, controlling for participant sex (ps < .05). In a hierarchical regression, pain intensity was related to polysomnography-measured total sleep time but not measures of sleep fragmentation (apnea-hypopnea index, spontaneous arousals) or hypoxemia (SaO2 nadir). Thus, although polysomnography measures of OSA severity were unrelated to pain intensity, individuals with comorbid OSA/insomnia had the most severe pain. Study results suggest that chronic pain was highly prevalent in this sleep clinic population, with the most severe pain reported by individuals with co-occurring OSA/insomnia. This has important clinical implications, as both chronic pain and insomnia have been shown to predict poorer adherence to positive airway pressure treatment of OSA.