High risk of fatal overdose on leaving heroin misuse treatment
Heroin addiction is associated with high standardised mortality rates, with drug overdose being the most common cause of death. A study has shown that the risk of fatal overdose for patients in the first month out of treatment for heroin addiction is 2.3%, a risk 26 times higher than for patients in treatment programmes.
The prospective cohort study recruited more than 10,000 heroin misusers at 115 treatment centres. Patients engaged in methadone maintenance treatment, residential treatment, detoxification or psychosocial interventions, and could have more than one treatment at one time.
Participants were followed up for 18 months, representing more than 10,000 person-years in treatment and almost 3,000 person-years out of treatment. Follow-up was complete for 96% of participants. Out of treatment was defined as starting the second day of absence of pharmacological treatment.
One hundred deaths occurred during the study period, with 41 caused by overdose. Overdose mortality out of treatment was more than 10 times higher than during treatment. Mortality rates because of overdose were particularly high in the first month out of treatment (HR 26.57, 95% CI 11.56-61.10), presumably because of reduced tolerance to opiates and relapse.
This study reinforces the value of a range of treatments for heroin dependence in reducing overdose mortality, and highlights the potential danger of leaving treatment.
GPs who see patients who misuse drugs need to be aware of the risks of post-treatment relapse and offer information and advice to anyone in this situation.
Davoli M, Bargagli AM, Perucci CA et al. Risk of fatal overdose during and after specialist drug treatment: the VEdeTTE study, a national multi-site prospective cohort study. Addiction 2007:102;1954-9Reviewer
Dr Jez Thompson
Former GP, Clinical Director, Leeds Community Drug Services