Abstract

Introduction: Patients with obstructive sleep apnea (OSA) and comorbid diabetes mellitus (DM) are reported to have an increased risk of cardiovascular (CV) outcomes; however, data on CV mortality are scant. Aim: This study aimed to evaluate if patients with comorbid OSA and DM have an increased risk of CV mortality that is higher than the two diseases in isolation. Methods: In this prospective cohort study, we included patients referred for a sleep study with and without DM at baseline. We developed four study groups as follows: group 1 (reference group), OSA (−) DM (−); group 2, OSA (−) DM (+); group 3, OSA (+) DM (−); group 4, OSA (+) DM (+). Intergroup differences were evaluated using the t test and χ2 test, and multivariate analysis was performed using logistic regression. The incidence rates of CV mortality were calculated using the Kaplan–Meier (log-rank) model, and adjusted HRs were calculated using the Cox regression model. Results: A total of 1447 patients were included in the analysis—group 1: 441 participants; group 2: 141 participants; group 3: 736 participants; group 4: 151 participants. The mean follow-up was 5 years. The association between OSA + DM showed an independent risk of incident CV mortality (HR 2.37, CI 1.16–4.82, p = 0.02) and an increased prevalence of coronary heart disease (OR 3.44, CI 1.73–5.59, p < 0.01). In addition, T90% was also associated with CV mortality. Conclusion: The coexistence of OSA + DM was associated with an independent risk of CV mortality. In addition, T90% was also associated with CV mortality.