Positive airway pressure therapy for chronic pain in patients with obstructive sleep apnea-a systematic review

Purpose Obstructive sleep apnea (OSA) is prevalent in patients with chronic non-cancer pain. OSA may lead to low sleep quality and an increase in pain sensitivity. Patients reporting greater sleep impairment tend to experience higher pain intensity and vice versa. Positive airway pressure (PAP) is the current gold standard treatment for OSA. This review aims to evaluate the efficacy of PAP therapy in patients with comorbid chronic pain and OSA in influencing pain outcomes like pain intensity, tolerance, threshold, and sensitivity. Methods We performed a systematic literature search for studies published after 1990, utilizing the following databases: Medline, Medline In-Process/ePubs, Embase, Cochrane CENTRAL, and the Cochrane Database of Systematic Reviews. Search terms included "chronic pain," "sleep disorders," and "positive airway pressure." Results Of 1982 initial studies, ten studies met the study inclusion criteria. Seven of these studies examined the effect of PAP therapy on chronic pain, of which five demonstrated improved pain outcomes, specifically, headache pain. The effect of PAP therapy on chronic non-headache pain was found to be inconclusive. When examining the three studies that did not involve chronic pain patients, PAP therapy effectively increased pain threshold and tolerance in two studies (p = 0.03 and p = 0.01). Conclusion An association exists between PAP therapy and decreased chronic headache outcomes in patients with OSA. Additionally, research shows that PAP therapy may increase pain tolerance and threshold. Future high-quality evidence is required to further investigate the association between PAP and non-headache chronic pain.