Correlates of pain in an in-treatment sample of opioid-dependent people

Introduction and Aims: The limited literature on pain in opioid-treatment samples indicates that it is highly prevalent. Understanding the implications of pain on treatment outcomes is important, particularly in light of ageing opioid-treatment cohorts. This study explores correlates of pain, including aberrant behaviours related to prescribed opioids. Our hypothesis is that pain may increase aberrant opioid-related behaviours, including illicit substance use, among opioid-dependent people.

Design and Methods: We examined pain in methadone or buprenorphine patients (n = 141) from three treatment services. Measures included basic demographics, Brief Pain Inventory, general mental health, physical health and quality of life measures, pain history and treatments, and an aberrant opioid-related behaviour scale. Univariate and multivariate analyses were used to examine correlates of pain.

Results: Forty percent reported current pain, measured with the first question of the Brief Pain Inventory. Correlates of pain were depression ratings [adjusted odds ratio (OR) 2.24, 95% confidence interval (CI) 1.04, 4.83], anxiety ratings (adjusted OR 4.29, 95% CI 1.88, 9.80) and self-reported health ratings (adjusted OR 0.35, 95% CI 0.16, 0.76). Contrary to our hypothesis, pain was not associated with greater use of illicit opioids, nor any aberrant opioid-related behaviours. Pain was comparable among methadone and buprenorphine patients.

Discussion and Conclusions: The lack of association with pain and aberrant behaviours suggest that it should not be assumed that those in opioid treatment misuse medications in response to pain. The high prevalence of depression/anxiety symptoms indicates a need for further work with larger samples to explore pain and co-morbidity among opioid-dependent people.