Comorbid obstructive sleep apnea and insomnia and its associations with mood and diabetes-related distress in type 2 diabetes mellitus

Study Objectives: Previous research suggests that obstructive sleep apnea (OSA) and insomnia frequently coexist and are prevalent in persons with type 2 diabetes mellitus. This study compared mood and diabetes-related distress among OSA, insomnia, and comorbid OSA and insomnia groups in persons with type 2 diabetes mellitus. Methods: A secondary analysis was conducted with baseline data from 2 independent randomized controlled trials evaluating the efficacy of OSA and insomnia treatment. The pooled sample (n = 224) included participants with OSA only (n = 68 [30.4%]), insomnia only (n = 107 [47.8%]), and OSA and insomnia (OSA+insomnia; n = 49 [21.9%]). OSA was defined as an apnea-hypopnea index >= 15 events/h; insomnia was defined as an Insomnia Severity Index score >= 15. Mood was measured by the Profile of Mood States total and subscale scores; diabetes-related distress was assessed by the Problem Areas in Diabetes questionnaire. One-way analysis of covariance and multivariate analysis of covariance were conducted, controlling for demographic characteristics and restless legs syndrome. Results: The insomnia group had on average significantly higher scores for total mood disturbance (insomnia vs OSA = 45.32 vs 32.15, P = .049), tension-anxiety (insomnia vs OSA = 12.64 vs 9.47, P = .008), and confusion-bewilderment (insomnia vs OSA = 9.45 vs 7.46, P= .036) than the OSA group. The OSA+insomnia group had on average significantly greater diabetes-related distress than the OSA group (OSA+insomnia vs OSA = 40.61 vs 30.97, P= .036). Conclusions: Insomnia may have greater impact on mood disturbance and diabetes-related distress than OSA in persons with type 2 diabetes mellitus. In particular, comorbid insomnia may contribute to greater diabetes-related distress in persons with type 2 diabetes mellitus and OSA.