The Complex Web of Intervening Variables Shared by Chronic Pain and Sleep Disorders

Background and aims: An estimated that 20% of the world's population suffers from chronic pain (CP) and 25% experience sleep disturbances. The concomitance of CP and sleep disorders (SD) negatively impact general health and well-being. Investigations of this complex relationship have been constrained by difficulty in acquiring valid data from people whose SD diagnoses are based on complete nocturnal polysomnography (NP) and multiple sleep latency tests (MSLT).

Methods: We constructed an 111-item questionnaire to use in conjunction with nocturnal polysomnography studies (NPS), multiple sleep latency tests, the Epworth Sleepiness Scale (ESS), and medical chart reviews of people referred for evaluation of SDs.

Results: We analyzed data from 718 people (317 females, 401 males) with a mean age of 49.32. Of these, 43% reported CP. Analyses of the CP versus no CP groups revealed numerous significant differences. For example, comparisons of the groups during NPS revealed those with CP had significantly greater prevalence of diagnoses of abnormal sleep architecture, nocturnal hypoxemia, and spent less time in stage N3. People with CP were more likely to have asthma, nasal/sinus problems, severe heartburn/acid reflux, depression, anxiety, difficulty concentrating, memory problems, stress, allergies, accidents related to sleepiness, nightmares, wake screaming, and bizarre dreams. They also were more likely to feel weak when angry or laughing, complain of sleepiness interfering with their social lives, and feel paralyzed when awakening.

Conclusions: We hope illuminating the relationship shared by CP and SD will contribute to enhancing successful pain management.