Pain Among High-Risk Patients on Methadone Maintenance Treatment

The complexity of treating concurrent pain and opioid dependence among many methadone-maintained individuals presents a major challenge in many clinical settings. Furthermore, recent expert guidelines have called for increased research on the safety of methadone in the context of chronic pain. This study explores the prevalence and correlates of pain among a prospective cohort of people who use illicit drugs in Vancouver, British Columbia, Canada, who reported enrollment in methadone maintenance treatment (MMT) between 2011 and 2014. Among the 823 participants eligible for this analysis, 338 (40.9%) reported moderate pain and 91 (11.1%) reported extreme pain at the first study visit. In multivariable, generalized, linear mixed model analyses, higher pain severity was positively and independently associated with self-managing pain (adjusted odds ratio [AOR] 2.15, 95% confidence interval [CI] 1.77-2.60), patient perception of methadone dose being too low (AOR 1.82, 95% CI 1.41-2.34), older age (AOR 1.31, 95% CI 1.13-1.51), having a physical disability (AOR 4.59, 95% CI 3.73-5.64), having ever been diagnosed with a mental illness (AOR 1.44, 95% CI 1.13-1.84), white ethnicity (AOR 1.42, 95% CI 1.10-1.83), and marijuana use (AOR 1.25, 95% CI 1.02-1.52). These findings suggest several areas for clinical intervention, particularly related to patient education and alternative analgesic approaches for MMT patients experiencing pain. Perspective: To better understand the complexity of concurrent pain and opioid dependency among individuals on methadone maintenance treatment, this article describes the prevalence and correlates of higher pain severity among methadone-maintained people who use illicit drugs. Patients on methadone with comorbid pain may benefit from education and alternative analgesic approaches. (C) 2015 by the American Pain Society