Aims: To compare the change in illicit opioid users' risk of fatal drug-related poisoning (DRP) associated with opioid agonist pharmacotherapy (OAP) and psychological support, and investigate the modifying effect of patient characteristics, criminal justice system (CJS) referral and treatment completion.
Design: National data linkage cohort study of the English National Drug Treatment Monitoring System and the Office for National Statistics national mortality database. Data were analysed using survival methods.
Setting: All services in England that provide publicly funded, structured treatment for illicit opioid users.
Participants: Adults treated for opioid dependence during April 2005 to March 2009: 151,983 individuals; 69% male; median age 32.6 with 442,950 person-years of observation.
Measurements: The outcome was fatal DRP occurring during periods in or out of treatment, with adjustment for age, gender, substances used, injecting status and CJS referral.
Findings: There were 1499 DRP deaths [3.4 per 1000 person-years, 95% confidence interval (CI) = 3.2-3.6]. DRP risk increased while patients were not enrolled in any treatment [adjusted hazard ratio (aHR) = 1.73, 95% CI = 1.55-1.92]. Risk when enrolled only in a psychological intervention was double that during OAP (aHR = 2.07, 95% CI = 1.75-2.46). The increased risk when out of treatment was greater for men (aHR = 1.88, 95% CI = 1.67-2.12), illicit drug injectors (aHR = 2.27, 95% CI = 1.97-2.62) and those reporting problematic alcohol use (aHR = 2.37, 95% CI = 1.90-2.98).
Conclusions: Patients who received only psychological support for opioid dependence in England appear to be at greater risk of fatal opioid poisoning than those who received opioid agonist pharmacotherapy.
Keywords: Drug-related poisoning; opiate dependence; opioid agonist pharmacotherapy; overdose; psychosocial treatment; residential treatment.
© 2015 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.