Impacts of a Medicaid “lock-in” program on opioid use disorder treatment and services and naloxone dispensing.

“Lock-in” programs are used by health insurers to reduce the risk of adverse outcomes that can result from overutilization of opioids and other controlled substances. We estimated the association between North Carolina’s Medicaid lock-in program and use of opioid use disorder treatment-related services and naloxone dispensing.
A cohort study of individuals who became eligible for a Medicaid lock-in program between December 2016 and December 2019 (n = 21,220). We compared those enrolled in the program to those eligible but not enrolled. Outcomes included rate of medication for opioid use disorder (MOUD); rate of other substance use disorder treatment (e.g., detoxification); and naloxone dispensing.
The majority of beneficiaries enrolled in the program had recently received MOUD or other treatment prior to enrollment (59%). After controlling for several potential confounders, the program was associated with slight increases in MOUD use, compared to those eligible but not enrolled (adjusted rate ratio: 1.09, 95% CI: 1.04,1.14). Those enrolled in the program received, on average, 5.4 more days of MOUD per person per year than those eligible but not enrolled (adjusted risk difference: 5.43, 95% CI: 2.49,8.36). Naloxone dispensing was similar and low among those enrolled and not enrolled in the program (7-8%).
Enrollment in a Medicaid lock-in program was associated with a small increase in the number of days with substance use disorder treatment. However, given the high prevalence of opioid use disorder among beneficiaries in the program, findings highlighted considerable opportunity for improvement in treatment utilization and retention and a need for increased naloxone dispensing.