Obstructive sleep apnea among survivors of combat-related traumatic injury: a retrospective cohort study

Study Objectives: Obstructive sleep apnea is prevalent among military members despite fewer traditional risk factors. We sought to determine the incidence and longitudinal predictors of obstructive sleep apnea in a large population of survivors of combat-related traumatic injury and a matched control group. Methods: Retrospective cohort study of military service members deployed to conflict zones from 2002–2016 with longitudinal follow-up in the Veterans Affairs and Military Health Systems. Two cohorts of service members were developed: (1) those who sustained combat injuries and (2) matched, uninjured participants. Results: 17,570 service members were retrospectively analyzed for a median of 8.4 years. After adjustment, traumatic brain injury (hazard ratio [HR] 1.39, 95% confidence interval [CI] 1.20–1.60), posttraumatic stress disorder (HR 1.24, 95% CI 1.05–1.46), depression (HR 1.52, 95% CI 1.30–1.79), anxiety (HR 1.40, 95% CI 1.21–1.62), insomnia (HR 1.71, 95% CI 1.44–2.02), and obesity (HR 2.40, 95% CI 2.09–2.74) were associated with development of obstructive sleep apnea. While combat injury was associated with obstructive sleep apnea in the univariate analysis (HR 1.25, 95% CI 1.17–1.33), the direction of this association was reversed in the multivariable model (HR 0.74, 95% CI 0.65–0.84). In a nested analysis, this was determined to be due to the effect of mental health diagnoses. Conclusions: The incidence of obstructive sleep apnea is higher among injured service members (29.1 per 1,000 person-years) compared to uninjured service members (23.9 per 1,000 person-years). This association appears to be driven by traumatic brain injury and the long-term mental health sequelae of injury.