Efficacy and cost-effectiveness of an adjunctive personalised psychosocial intervention in treatment-resistant maintenance opioid agonist therapy: a pragmatic, open-label, randomised controlled trial.

BACKGROUND:Opioid use disorder is a chronic, debilitating, and costly disorder that has increased in prevalence in many countries, with an associated sharp rise in mortality. Maintenance opioid agonist therapy is the first-line treatment, but many patients do not stop using illicit or non-prescribed drugs concomitantly. We aimed to test the efficacy and cost-effectiveness of a personalised psychosocial intervention implemented with a toolkit of behaviour-change techniques as an adjunct to opioid agonist therapy. METHODS:We did a pragmatic, open-label, randomised controlled trial at a specialist UK National Health Service community addictions clinic in London, UK. Eligible patients were aged 18 years or older, met criteria for opioid or cocaine dependence, or both, in the past 12 months, and voluntarily sought continued oral maintenance opioid agonist therapy, which they had been prescribed for at least 6 weeks. All participants were treatment resistant (ie, had used illicit or non-prescribed opioids or cocaine on one or more days in the past 28 days at study screening, which was verified by positive urine drug screen). Participants were allocated (1:1) by a web-accessed randomisation sequence (stratified by opioid agonist medication, current cocaine use, and current rug use) to receive a personalised psychosocial intervention (comprising a flexible toolkit of psychological-change methods, including contingency management to reinforce abstinence, recovery activities, and clinic attendance) in addition to treatment as usual, or treatment as usual only (control group). The primary outcome was treatment response at 18 weeks, which was defined as abstinence from illicit and non-prescribed opioids and cocaine in the past 28 days, as measured with treatment outcomes profiles and urine drug screening. Taking a societal cost perspective, we did an evaluation of cost-effectiveness with a wide range of willingness-to-pay values for a unit improvement in the probability of treatment response. We also calculated quality-adjusted life-years (QALYs). Efficacy was analysed in a modified-intention-to-treat population, including all participants who were randomly allocated but excluding those who had previously completed the intervention. This trial is registered with ISRCTN, number ISRCTN69313751. The trial is completed. FINDINGS:Between June 7, 2013, and Dec 21, 2015, we randomly allocated 136 participants to the psychosocial intervention group and 137 to the control group. The trial database was locked on April 19, 2017. Three patients (one in the psychosocial intervention group and two in the control group) who were re-randomised in error were excluded from the analysis. 22 (16%) of 135 patients in the psychosocial intervention group had a treatment response, compared with nine (7%) of 135 in the control group (adjusted log odds 1·20 [95% CI 0·01-2·37]; p=0·048). The psychosocial intervention had a higher probability of being cost-effective than treatment as usual. There was a probability range of 47-87% for willingness-to-pay thresholds of £0-1000 for a unit improvement in the probability of treatment response. QALYs were higher in the psychosocial intervention group than in the control group (mean difference 0·048 [95% CI 0·016-0·080]; p=0·004) in adjusted analyses, with 60% and 67% probabilities of cost-effectiveness at the UK National Institute for Health and Care Excellence's willingness-to-pay thresholds of £20 000 and £30 000 per QALY, respectively. The number of adverse events was similar between groups, and no severe adverse events in either group were judged to be treatment related. One participant in the control group was hospitalised with drug-injection-related sepsis and died. INTERPRETATION:In maintenance opioid agonist therapy, an adjunctive personalised psychosocial intervention in addition to standard therapy was efficacious and cost-effective compared with standard therapy alone at helping treatment-resistant patients abstain from using illicit and non-prescribed opioids and cocaine. FUNDING:Indivior.