Impact of low arousal threshold on treatment of obstructive sleep apnea in patients with post-traumatic stress disorder

Purpose: We sought to determine the prevalence of low arousal threshold (LAT) in veterans with post-traumatic stress disorder (PTSD) and whether or not LAT is associated with decreased use of continuous positive airway pressure (CPAP). Methods: We conducted a retrospective study of all veterans with documented PTSD who had an apnea hypopnea index > 5/h over a 27-month period. Demographic, clinical characteristics, and CPAP usage were extracted from the medical records. A multivariate analysis was conducted to assess predictors of CPAP use at 3 months in patients with LAT after adjusting for severity of PTSD. Results: LAT was identified in 55% of 119 patients with PTSD and newly diagnosed OSA. LAT was associated with younger age (odds ratio [OR] 0.91; 95% confidence interval [CI] 0.86–0.95), lower BMI (OR 0.82; 95% CI 0.73–0.91), presence of insomnia (OR 1.34; 95% CI 1.19–1.81), and use of antidepressant (OR 1.14; 95% CI 1.09–2.01). PTSD severity, REM rebound, and the presence of baseline comorbid insomnia were each associated with CPAP use at 3 months. Neither daytime sleepiness, body mass index (BMI), nor LAT endotype was correlated with CPAP utilization. Insomnia was the only factor associated with decreased CPAP use in patients with PTSD and LAT (P = 0.04). Conclusion: The LAT endotype is common among veterans with PTSD. An improved understanding of how insomnia in this population affects CPAP utilization would be instrumental in designing targeted therapy to improve sleep quality.