Residual sleepiness in veterans with post-traumatic stress disorder and obstructive sleep apnea

Purpose The causes of residual excessive sleepiness (RES) in patients with post-traumatic stress disorder (PTSD) and obstructive sleep apnea (OSA) are multifactorial and modulated by comorbid conditions. The aim of the present study was to elucidate clinical and polysomnographic determinants of RES in continuous positive airway pressure (CPAP)-adherent OSA veterans with PTSD. Methods The study protocol consisted of a retrospective analysis of consecutive cases of patients with PTSD who presented to the Veterans Affairs sleep clinics with adequately treated OSA between June 1, 2017 and October 15, 2021. Based on the Epworth Sleepiness Scale (ESS), patients were categorized into RES (ESS ≥ 11) and no RES (ESS < 11) groups. Demographic and PSG data were subjected to univariate and multivariate analyses to ascertain predictive factors of RES. Results Out of 171 veterans with PTSD who were adherent to CPAP, 59 (35%) continued to experience RES. The RES group had a decrease in mean ESS score of 1.2 ± 4.5 after CPAP treatment compared with 4.6 ± 4.9 for the no RES group (< 0.001). A dose–response was observed between CPAP use and RES ( p = 0.003). Multivariate regression analysis identified higher baseline ESS (OR 1.30; 95% CI 1.16–1.44), greater percentage of time spent in REM sleep (OR 0.91; 95% CI 0.85–0.96), CPAP use less than 6 h (OR 2.82; 95% CI 1.13–7.01), and a positive screen for depression (OR 1.69; 95% CI 1.03–4.72) as independent predictors of RES in patients with PTSD and OSA. Conclusion RES is highly prevalent in patients with PTSD and OSA despite adherence to CPAP and is independently associated with percentage time spent in REM, duration of CPAP utilization, and symptoms of depression.