Cost-effectiveness analysis of a large jail-based methadone maintenance treatment continuation program in New Mexico

The U.S. has the second-highest incarceration rate in the world and spends more than $80 billion annually to house inmates. The clinical research literature suggests that methadone maintenance treatment (MMT) is an effective method to treat opioid use disorders (OUD) and that jails are a potentially valuable environment to implement MMT. Currently, jail-based MMT is rarely implemented in practice, due in part to resource limitations and other economic considerations. The primary goal of this study was to perform a cost-effectiveness analysis (CEA) of jail-based MMT using data from a unique MMT continuation program located in a large urban jail in New Mexico. Recidivism data were collected for a three-year period both before and after incarceration, and quasi-control groups were constructed from both substance-using and general populations within the jail. Base models show that inmates enrolled in jail-based MMT exhibited significantly fewer days of incarceration due to recidivism (29.33) than a group of inmates with OUDs who did not receive MMT. Economic estimates indicate that it cost significantly less ($23.49) to reduce an incarcerated day using jail-based MMT than incarceration per se ($116.49). To mitigate potential sample selection bias, we used both propensity-score-matching and difference-in-differences estimators, which provided comparable estimates when using the OUD non-MMT comparison group. Difference-in-differences models find that, on average, MMT reduced recidivism by 24.80 days and it cost $27.78 to reduce an incarcerated day using jail-based MMT. Assuming a willingness to pay threshold of the break-even cost of reducing one incarcerated day, we estimate a 93.3% probability that this MMT program is cost-effective. Results were not as strong or consistent when using other comparison groups (e.g., alcohol-detoxified and general-population inmates). Overall, results suggest that it costs substantially less to provide jail-based MMT than incarceration alone. Jail administrators and policymakers should consider incorporating MMT in other jail systems and settings.