Diabetes mellitus is associated with increased prevalence and severity of COMISA: evidence from the nationwide TURKAPNE cohort

BACKGROUND: Comorbid insomnia and obstructive sleep apnea (COMISA) is increasingly recognized as a clinically important sleep disorder phenotype with potential cardiometabolic consequences. However, its association with diabetes mellitus (DM) remains insufficiently characterized. METHODS: This cross-sectional analysis included 12,715 adults with suspected obstructive sleep apnea (OSA) from the nationwide multicenter TURKAPNE cohort who underwent full-night polysomnography. Insomnia symptoms were assessed using standardized questionnaire items, and OSA was defined as apnea-hypopnea index (AHI) ≥ 5 events/hour. COMISA was defined as the coexistence of insomnia symptoms and OSA. DM was identified based on self-reported physician diagnosis or use of antidiabetic medications. Multivariable logistic regression was performed to evaluate independent variables associated with COMISA. RESULTS: COMISA was present in 3,275 patients (25.7%). DM was significantly more prevalent among patients with COMISA compared with those without COMISA (22.8% vs. 15.4%, p < 0.001). Overall, COMISA was observed in 33.9% of diabetic individuals and 24.1% of non-diabetic individuals. In multivariable analysis adjusted for age, sex, body-mass-index, smoking status, education level, and comorbidities, DM remained independently associated with COMISA (adjusted OR 1.17; 95% CI 1.05-1.31; p = 0.006). Among COMISA patients, those with DM exhibited greater sleep fragmentation and more severe sleep-disordered breathing, including higher AHI (30.0 vs. 24.0 events/h) and oxygen desaturation index (26.0 vs. 20.0 events/h) (p < 0.001). CONCLUSIONS: DM is independently associated with COMISA and with more severe sleep and respiratory disturbances within this phenotype. These findings highlight the need for integrated screening of sleep disorders in individuals with DM. TRIAL REGISTRATION: ClinicalTrials gov (NCT02784977).