The bidirectional relationship between sleep complaints and pain: Analysis of data from a randomized trial

Objective: The goal of this study was to examine the bidirectional relationship of sleep and pain to determine whether changes in sleep complaints over the course of a chronic pain treatment trial predict pain outcomes and vice versa, controlling for changes in depression and anxiety. Methods: Data were analyzed from a 12-month randomized, controlled trial that tested the effectiveness of a collaborative care intervention for veterans with chronic musculoskeletal pain. Participants were 250 veterans from 5 primary care clinics in a Veteran Affairs (VA) medical center. Measures of pain, sleep, and depression/anxiety symptoms were collected at baseline, 3 months, and 12 months. Factor analysis was used to clarify the boundaries of these domains, and structural equation modeling was used to examine whether changes in sleep complaints and depression/anxiety during the trial predicted pain at the end of the trial, controlling for covariates. An alternative model was also tested in which changes in pain predicted sleep complaints. Results: Changes in sleep complaints at 3 months significantly predicted changes in pain at 12 months (standardized path coefficient =.29, p <.001). To a lesser extent, changes in pain predicted changes in sleep (standardized path coefficient =.15, p <.05). Changes in depression/anxiety did not significantly predict changes in pain or sleep. There was also evidence of differential relations of specific sleep complaints with pain. Conclusions: This work helps to further disentangle the complex relationship between pain and sleep. This bidirectional relationship may need to be considered to improve pain outcomes.