ObjectiveThe purpose of this study was to describe incidence and assess predictors of adherence to Positive Airway Pressure (PAP) therapy for Obstructive Sleep Apnea (OSA) in persons with acquired brain injury (ABI). MethodsA 2012–2015 retrospective analysis of consecutive ABI patients admitted for neurorehabilitation, referred for polysomnography (PSG), and prescribed PAP for OSA. Univariable linear regressions were conducted to examine predictors of average hours of nightly PAP use. Univariable logistic regressions were conducted to examine predictors of PAP adherence using the conventional clinical definition of ≥4 h per night ≥70% of the time. Persons with traumatic etiology were separately analyzed. ResultsABI etiology was 51% traumatic, 36% stroke, and 13% other nontraumatic causes. Nearly two-thirds were nonadherent to PAP. For the overall sample, higher average nightly PAP usage was significantly predicted by positive hypertension diagnosis (β = 0.271, p = 0.019). Likewise, greater adherence based on the conventional cutoff was predicted by poorer motor functioning at hospital admission (OR = 0.98, p = 0.001) and lower oxygen saturation nadir (OR = 0.99, p = 0.003). For those with traumatic injuries, greater adherence was predicted by poorer functional status at hospital admission (OR = 0.98, p = 0.010) and positive hypertension diagnosis (OR = 0.16, p = 0.023). ConclusionsIn this study of hospitalized neurorehabilitation patients with ABI and comorbid OSA, predictors of adherence included lower oxygen saturation, poorer functional status and hypertension diagnosis, perhaps signifying the role of greater severity of illness on treatment adherence. High rates of refusal and nonadherence to frontline PAP therapy for sleep apnea is a concern for persons in recovery form ABI who are at a time of critical neural repair.