I'm tired and it hurts! Sleep quality and acute pain response in a chronic pain population

Objective/Background: There are bidirectional links between sleep quality and pain, with recent research suggesting that sleep impairment more strongly predicts future pain than vice versa. Relatively few studies have examined the relationship between sleep quality and acute pain among chronic pain patients. The purpose of the current study is to investigate relationships among subjective sleep quality and behavioral and physiological responses to a cold pressor pain task (CPT) in chronic pain patients. Patients/methods: In sum, 120 individuals with chronic pain were included. Participants completed a series of questionnaires followed by the CPT. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Physiological baseline state and stress response were assessed before and during the CPT using heart rate (HR), electromyography frontalis (EMGF), galvanic skin response conductance (GSR), and skin temperature (degrees C). Multiple linear regressions adjusting for opioid usage were performed. Results: After adjusting for opioid use, PSQI global score explained significant variance in pain tolerance (B = -5.37, beta = -0.23, p = 0.01), baseline GSR (B = -0.66, beta = -0.24, p = 0.01), and HR change from baseline to CPT (B = 1.33, beta = 0.25, p = 0.01). Conclusions: Worse perceived sleep quality was associated with lower pain tolerance, lower baseline GSR conductance, and greater HR change from baseline to CPT. These findings underscore the importance of accounting for opioid usage and psychological dimensions of pain in the relationship between sleep and acute pain response in chronic pain populations. (C) 2019 Elsevier B.V. All rights reserved.