Predicting biopsychosocial outcomes for heroin users in primary care treatment: a prospective longitudinal cohort study.

Background Opiate substitution treatment for heroin users reduces mortality, illicit drug use, crime, and risk-taking behaviour, and improves physical, mental and social functioning. Few extended studies have been carried out in UK primary care to study factors predicting recovery. Aim To establish whether primary care opiate substitution treatment is associated with improvements in outcomes over 11 years, in delivering recovery, and to identify predictive factors. Design and setting A prospective longitudinal cohort study, with repeated measures in the Primary Care Addiction Service, Sheffield, 1999–2011. Method A total of 123 eligible patients were assessed using the Opiate Treatment Index at entry to treatment and at 1, 5, and 11 years. Clinical records were used to assess factors including employment and discharge status. Results At 11 years, there was a high rate of drug-free discharge (22.0%) and medically-assisted recovery (30.9%), and low mortality (6.5%). Continuous treatment was associated with being discharged drug free ( P = 0.005). For those still in treatment, there were highly significant reductions in heroin use and injecting, and significantly improved psychosocial functioning. There were strong positive correlations between mental health, physical health, and social functioning. Patients in employment had significantly better psychological and social functioning ( P = 0.017, P = 0.007, respectively). Conclusion Opiate substitution treatment is associated over 11 years with full recovery, drug-free discharge and medically-assisted recovery. There is a strong association between the psychosocial variables, suggesting that intervention in any one of these areas may have extended benefits, by impacting on related variables and employment. The best predictor of a drug-free discharge was continuous uninterrupted treatment.