title: Predictors of non-prescribed opioid use after one year of methadone treatment: an attributable-risk approach (ANRS-Methaville trial).
abstract: BACKGROUND
  The effectiveness of methadone as an opioid maintenance treatment (OMT) for opioid dependence has been widely demonstrated. However many patients continue to use other opioids while on methadone treatment. Studies assessing avoidable cases of continued non-prescribed opioid use during methadone treatment are sparse.
  
  
  METHODS
  At 12 months of treatment (M12), 158 subjects had available data on opioid use, measured using the Opiate Treatment Index. We identified variables associated with non-prescribed opioid use at M12, using a univariate logistic regression and two multivariate models, one incorporating only pre-treatment variables, the second adding the in-treatment variables. We also calculated attributable fractions for risk factors.
  
  
  RESULTS
  At M12, 32.3% of the patients had used non-prescribed opioids during the previous month. A good patient-physician relationship was the most influential factor associated with not using non-prescribed opioids after one year. Living with a heroin user after one year of treatment, using cocaine during treatment and hazardous alcohol consumption at enrolment were all associated with an increased risk of non-prescribed opioid use at M12. Analysis of attributable fractions indicated that living with a heroin user at M12 accounted for 21% of patients reporting non-prescribed opioid use at M12, while the lack of a good relationship with the physician accounted for 26%.
  
  
  CONCLUSIONS
  The attributable risk approach suggests that continued non-prescribed opioid use by a considerable proportion of individuals could potentially be reduced by improving patient-physician relationships, enhancing care for co-dependent patients and encouraging patients to modify their social network.
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France. Electronic address: caroline.lions@inserm.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lions
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France.
authors.forename: M Patrizia
authors.initials: MP
authors.lastname: Carrieri
authors.affiliation: INSERM, Research Unit 669, Paris, France; Univ. Paris-Sud and Univ. Paris Descartes, UMR-S0669, Paris, France; Centre Pierre Nicole, Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Michel
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Mora
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Marcellin
authors.affiliation: Oppelia, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Morel
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Spire
authors.affiliation: INSERM, UMR912 "Economics and Social Sciences Applied to Health & Analysis of Medical Information" (SESSTIM), 13006 Marseille, France; Aix Marseille University, UMR_S912, IRD, 13006 Marseille, France; ORS PACA, Southeastern Health Regional Observatory, 13006 Marseille, France.
authors.forename: Perrine
authors.initials: P
authors.lastname: Roux
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage*; D009293:Opioid-Related Disorders / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology; D011237:Predictive Value of Tests; D012307:Risk Factors; D057566:Self Report; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D008691:Methadone
keywords: Attributable-risk factors; Methadone treatment; Non-prescribed opioid use; Physician–patient relation