Objective: There are few data about the incarceration of opioid-dependent people involving large representative cohorts. We aimed to determine the prevalence and duration of incarceration in a large cohort of opioid-dependent people in Australia using data linkage methods, and estimate the costs associated with their incarceration.
Method: Retrospective linkage study of all entrants to opioid substitution therapy (OST) for the treatment of opioid dependence in NSW, 1985–2010, with data on incarceration, 2000–2012. The number and duration of incarcerations were calculated. The average daily cost of incarceration was applied to days of incarceration in the cohort.
Results: Among 47,196 opioid-dependent people, 37% (43% of men and 24% of women) had at least one episode of incarceration lasting one or more days. Men had a median of three (ranging between 1–47) incarcerations, and women, two (1–35). Indigenous men spent 23% of follow-up time incarcerated, compared with 8% for non-Indigenous men; similarly, Indigenous women spent a substantially greater proportion of time incarcerated than non-Indigenous women (8% vs. 2%). Costs of incarceration of this cohort between 2000 and 2012 totalled nearly AUD$3 billion.
Conclusions: This is the first study to examine incarceration of opioid-dependent people across an entire population of such users. Our findings suggest that a substantial minority of opioid-dependent people experience incarceration, usually on multiple occasions and at significant cost. Treatment for opioid dependence, inside and outside prisons, may help reduce incarceration of this cohort.