An economic evaluation of the prison methadone program in New South Wales

Objectives - The aim of this study is to evaluate the costs and consequences of the provision of the prison methadone program in NSW, compared with no prison methadone. Methods - This study has measured the costs involved in the provision of the prison methadone program in NSW. The overall cost of the prison methadone program was estimated from a governmental perspective, incorporating the costs associated with the administration of the program, staffing requirements, methadone syrup and consumables. Both bottom-up and top-down costing approaches have been used. Both the total cost of the program and the cost per inmate in treatment are presented. The study is based on a follow-up study of a randomised trial of prison methadone in the NSW prison system (Dolan, Shearer et al. 2003). Although methadone is available to prisoners in many NSW prisons, the aim of the trial was to determine the impact of prison methadone on a range of health and social outcomes. Participants were randomised to receive prison methadone immediately or to be waitlisted. Waitlisted inmates were offered methadone after a four month delay. The cohort recruited by Dolan et al is now the subject of a four year follow-up study. Since all subjects had been offered methadone at the conclusion of the RCT, this could no longer be treated as controlled study. This limits the utility of the study outcome data for the economic evaluation. In the absence of comparative outcome data, a threshold analysis has been performed to determine what magnitude of outcomes is required to render the prison methadone program cost-neutral from a governmental perspective. The threshold analysis assumes that, through the provision of prison methadone, patients will gain from the benefits associated with continuous methadone treatment. Thus future criminal activity will be reduced and re-incarceration may be avoided. The analysis determines how many days of re-incarceration must be avoided to offset the annual cost of the methadone program. Firstly the analysis estimates what additional resources are required in the prison system to deliver prison methadone. Secondly, potential cost savings associated with avoided re-incarceration are estimated. The costs of the prison methadone program are then compared with the cost savings accrued by avoided days of re-incarceration and the level of effectiveness required to equate costs and savings is identified. A second threshold analysis assumes that, in addition to avoiding days of re-incarceration, prison methadone also avoids incident cases of Hepatitis-C. Given the cost of the program and the number of avoided cases of Hepatitis-C, the threshold analysis identifies the level of effectiveness, in terms of avoided re-incarceration, at which methadone treatment becomes cost neutral. Results - The total cost of providing prison methadone to 900 inmates in 21 prisons in NSW is $2.9million per annum. The cost per person year is $3,234. Given that the average daily cost of incarceration is $176, the annual cost of prison methadone is offset by avoiding 20 days of re-incarceration once the inmate is released. If avoided incident cases of hepatitis-C are included in the analysis, the annual cost of prison methadone is offset by avoiding 19 days of re-incarceration once the inmate is released. Conclusions - This analysis shows that, despite significant barriers to efficiency, prison methadone compares favourably to community based methadone on the basis of cost alone. The analyses suggests that, irrespective of whether avoided cases of Hepatitis-C are included, approximately 20 days of reincarceration must be avoided to offset the annual cost of methadone treatment. There appears to be no evidence in the literature to prove or disprove the feasibility of prison methadone maintenance avoiding such a period of re-incarceration.