title: Pain Among High-Risk Patients on Methadone Maintenance Treatment.
abstract: 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.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada; School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Pauline
authors.initials: P
authors.lastname: Voon
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Kanna
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of British Columbia, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Milloy
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Nguyen
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of British Columbia, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of British Columbia, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of British Columbia, St. Paul's Hospital, Vancouver, BC, Canada. Electronic address: uhri-tk@cfenet.ubc.ca.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000009:adverse effects*; D002170:Canada; D059350:Chronic Pain / Q000188:drug therapy*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000009:adverse effects*; D008875:Middle Aged; D015999:Multivariate Analysis; D058850:Opiate Substitution Treatment / Q000379:methods*; D009293:Opioid-Related Disorders / Q000453:epidemiology* / Q000628:therapy*; D017288:Pain Threshold / Q000187:drug effects
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone
keywords: Pain; methadone; opioid-induced hyperalgesia; self-medication; substance abuse