Effectiveness of treatment for opioid use disorder: A national, five-year, prospective, observational study in England

Background. This the first 5-year effectiveness study of publicly funded treatment for opioid use disorder (OUD) in England. Methods: All adults initiating treatment in 2008/09 in all 149 local treatment systems reporting to the National Drug Treatment Monitoring System (n = 54,347). Admission polydrug use sub-populations were identified by Latent Class Analysis. The treatment outcome measure was 'successful completion and no re-presentation within six months' (SCNR) analysed by multilevel, multivariable logistic regression and funnel plots to contrast outcome by treatment system. Results: SCNR was achieved by 21.9%. Heroin and crack cocaine users were significantly less likely to achieve this outcome than patients who used heroin only (adjusted odds ratio [AOR] 0.90; 95% confidence interval [CI] 0.85-0.95). Older patients (AOR 1.09; CI 1.07-1.11), those employed (AOR 1.27; CI 1.18-1.37) and those enrolled for longer treatment were more likely to achieve the outcome measure. After risk adjustment, the local treatment systems that achieved substantially better outcome performance (14/149) had a lower rate of opiate prevalence in the local population at time of study initiation (incidence rate difference [IRD] 4.1; CI 4.0-4.2), fewer criminal offences per thousand (IRD 28.5; CI 28.1-28.8) and lower drug-related deaths per million (IRD 5.9; CI 5.9-5.9). Conclusions: In an English national study, one fifth of patients successful completed treatment for OUD and did not present for further treatment within six months. Longer time in treatment increases the probability of achieving and maintaining clinical benefit from treatment. After risk-adjustment, an important minority of treatment systems achieve substantially better outcome performance.