title: Usefulness of the Brief Pain Inventory in Patients with Opioid Addiction Receiving Methadone Maintenance Treatment.
abstract: BACKGROUND
  Chronic pain is implicated as a risk factor for illicit opioid use among patients with opioid addiction treated with methadone. However, there exists conflicting evidence that supports and refutes this claim. These discrepancies may stem from the large variability in pain measurement reported across studies.
  
  
  OBJECTIVE
  We aim to determine the clinical and demographic characteristics of patients reporting pain and evaluate the prognostic value of different pain classification measures in a sample of opioid addiction patients.
  
  
  METHODS
  Multi-center prospective cohort study.
  
  
  METHODS
  Methadone maintenance treatment facilities for managing patients with opioid addiction.
  
  
  METHODS
  This study includes participants from the Genetics of Opioid Addiction (GENOA) prospective cohort study. We assessed the prognostic value of different pain measures for predicting opioid relapse. Pain measures include the Brief Pain Inventory (BPI) and patients' response to a direct pain question all study participants were asked from the GENOA case report form (CRF) "are you currently experiencing or have been diagnosed with chronic pain?" Performance characteristics of the GENOA CRF pain measure was estimated with sensitivity and specificity using the BPI as the gold standard reference. Prognostic value was assessed using pain classification as the primary independent variable in an adjusted analysis using 1) the percentage of positive opioid urine screens and 2) high-risk opioid use (= 50% positive opioid urine screens) as the dependent variables in a linear and logistic regression analyses, respectively.
  
  
  RESULTS
  Among participants eligible for inclusion (n = 444) the BPI was found to be highly sensitive, classifying a large number of GENOA participants with pain (n = 281 of the 297 classified with pain, 94.6%) in comparison to the GENOA CRF (n = 154 of 297 classified with pain, 51.8%). Participants concordantly classified as having pain according to the GENOA CRF and BPI were found to have an estimated 7.79% increase in positive opioid urine screens (estimated coefficient: 7.79; 95% CI 0.74, 14.85: P = 0.031) and a 4 times greater odds (odds ratio [OR]: 4.10 P = 0.008; 95% CI: 1.44, 11.63) of engaging in a "high risk" level of illicit opioids use. The prognostic relevance of pain classification was not maintained for the additional participants classified by the BPI (n = 143 discordant).
  
  
  CONCLUSIONS
  These results suggest that while the BPI may be more sensitive in capturing pain among patients with opioid addiction, this tool is of less value for predicting the impact of pain on illicit opioid use for opioid addiction patients on methadone maintenance treatment. The GENOA CRF showed high predictive ability, whereby patients classified according to the GENOA CRF are at serious risk for opioid relapse. Using the appropriate tool to assess pain in opioid addiction may serve to improve the current detection and management of comorbid pain.
  
  
  CONCLUSIONS
  We caution the interpretation of these result since they are still reflective of participants already maintained on an opioid substitution therapy (OST), which can largely differ from patients who drop out of methadone maintenance treatment (MMT) or never seek treatment altogether.
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada; Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada.
authors.forename: Brittany B
authors.initials: BB
authors.lastname: Dennis
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors.forename: Pavel S
authors.initials: PS
authors.lastname: Roshanov
authors.affiliation: Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada; McMaster Integrative Neuroscience Discovery & Study (MiNDS) Program, McMaster University, Hamilton, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Bawor
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada; Department of Anesthesia, McMaster University, Hamilton, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Paul
authors.affiliation: Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Varenbut
authors.affiliation: Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada.
authors.forename: Jeff
authors.initials: J
authors.lastname: Daiter
authors.affiliation: Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Plater
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors.forename: Guillame
authors.initials: G
authors.lastname: Pare
authors.affiliation: Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada; Northern Ontario School of Medicine, Sudbury, Ontario, Canada;
authors.forename: David C
authors.initials: DC
authors.lastname: Marsh
authors.affiliation: Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada; Department of Medicine, Hamilton General Hospital, Hamilton, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Worster
authors.affiliation: Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada; Departments of Pediatrics and Anesthesia, McMaster University, Hamilton, Canada;
authors.forename: Dipika
authors.initials: D
authors.lastname: Desai
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada; Departments of Pediatrics and Anesthesia, McMaster University, Hamilton, Canada; Centre for Evaluation of Medicine, St Joseph's Healthcare-Hamilton, Canada; Biostatistics Unit, Father Sean O'Sullivan Research Centre, St Joseph's Healthcare-Hamilton, Canada;
authors.forename: Lehana
authors.initials: L
authors.lastname: Thabane
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada; Population Genomic Program, Chanchalani Research Centre, McMaster University, Hamilton, Canada; Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Canada; Peter Boris Centre for Addictions Research, Canada.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Samaan
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000494:pharmacology / Q000627:therapeutic use; D059350:Chronic Pain / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008691:Methadone / Q000494:pharmacology / Q000627:therapeutic use*; D008875:Middle Aged; D058850:Opiate Substitution Treatment / Q000379:methods; D009293:Opioid-Related Disorders / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods*; D010865:Pilot Projects; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone