0035 Development of 12 poisoning and drug overdose case definitions for use with emergency department data in North Carolina

Evaluation of a Medicaid Lock-in Program: Increased Use of Opioid Use Disorder Treatment but No Impact on Opioid Overdose Risk

BACKGROUND

"Lock-in" programs (LIPs) identify beneficiaries demonstrating potential overutilization of opioids, and other controlled substances, and restrict their access to these medications. LIPs are expanding to address the opioid crisis and could be an effective tool for connecting people to opioid use disorder treatment. We examined the immediate and sustained effects of a Medicaid LIP on overdose risk and use of medication-assisted treatment (MAT) for opioid use disorder.

METHODS

We analyzed North Carolina Medicaid claims from July 2009 through June 2013. We estimated daily risk differences and ratios of MAT use and overdose during lock-in and following release from the program, compared with periods before program enrollment.

RESULTS

The daily probability of MAT use during lock-in and following release was greater, when compared with a period just before LIP enrollment [daily risk ratios: 1.50, 95% confidence interval (CI): 1.18-1.91; 2.27, 95% CI: 1.07-4.80; respectively]. Beneficiaries' average overdose risk while enrolled in the program and following release was similar to their risk just before enrollment (daily risk ratios: 1.01, 95% CI: 0.79-1.28; 1.12, 95% CI: 0.82-1.54; respectively).

DISCUSSION

North Carolina's Medicaid LIP was associated with increased use of MAT during enrollment, and this increase was sustained in the year following release from the program. However, we did not observe parallel reductions in overdose risk during lock-in and following release. Identifying facilitators of MAT access and use among this population, as well as potential barriers to overdose reduction are important next steps to ensuring effective LIP design.