Continuous uninterrupted opiate substitution treatment for heroin users is the best predictor of drug-free discharge, a UK primary care-based study has shown.

The prospective longitudinal cohort study was set in a GPwSI-led community drug service in Sheffield. Of 128 eligible patients entering treatment for opiate dependence in 1999, 123 were interviewed at baseline, with follow-up at one, five and 11 years. The Opiate Treatment Index was used as the primary assessment tool, and has outcome domains including drug use, BBV risk-taking behaviour, social functioning, criminal behaviour, health status and psychological wellbeing.

The average age of patients entering the study was 28 years, with a mean age of first heroin use of 20 years. Virtually all the participants (98%) were male, and more than half (56%) had previously been in prison. Nearly all were injecting heroin at baseline (94%), and 86% were unemployed.

At 11 years, 22% of patients had been discharged drug-free and 30.9% were undergoing medically assisted recovery.

Continuous treatment was associated with being discharged drug-free, P = 0.005. Multiple treatment episodes were associated with staying in treatment long-term, P = 0.026.

The drop-out rate was 14.6% and mortality rate 6.5%. For those still in treatment there had been highly significant reductions in heroin use and injecting and significantly improved social functioning.

The prevalence of depression had reduced in the study cohort from 45.5% to 9.1% and anxiety from 57.6% to 15.2%. There was a strong correlation between the psychosocial variables of physical health, psychological health and social functioning, suggesting that interventions to improve any one of these areas may have a positive impact on other variables.

The best predictor of drug-free discharge was continuous uninterrupted treatment.

This study focusing on treatment in primary care over a period of 11 years is the longest study of its kind in the UK. It demonstrates the effectiveness of primary care-based opiate substitution treatment over an extended period.

The authors recommend that to achieve drug-free discharge patients should be retained in uninterrupted treatment where possible, and that interventions to support recovery should seek to improve patients’ mental, physical and social functioning including employment.

Dr Jez Thompson