Evaluating short- and long-term impacts of a Medicaid "lock-in" program on opioid and benzodiazepine prescriptions dispensed to beneficiaries.

BACKGROUND: Insurance-based "lock-in" programs (LIPs) have become a popular strategy to address controlled substance (CS) (e.g., opioid) misuse. However, little is known about their impacts. We examined changes in CS dispensing to beneficiaries in the 12-month North Carolina Medicaid LIP. METHODS: We analyzed Medicaid claims linked to Prescription Drug Monitoring Program (PDMP) records for beneficiaries enrolled in the LIP between October 2010 and September 2012 (n=2702). Outcomes of interest were 1) number of dispensed CS prescriptions and 2) morphine milligram equivalents (MMEs) of dispensed opioids while a) locked-in and b) in the year following release. RESULTS: Compared to a period of stable CS dispensed prior to LIP enrollment, numbers of dispensed CS during lock-in and post-release were lower (count difference per person-month: -0.05 (95% CI: -0.11, 0.01); -0.23 (95% CI: -0.31, -0.15), respectively). However, beneficiaries' average daily MMEs of opioids were elevated during both lock-in and post-release (daily mean difference per person: 18.7 (95% CI: 13.9, 23.6); 11.1 (95% CI: 5.1, 17.1), respectively). Stratification by payer source revealed increases in using non-Medicaid (e.g., out-of-pocket) payment during lock-in that persisted following release. CONCLUSION: While the LIP reduced the number of CS dispensed, the program was also associated with increased acquisition of CS prescriptions using non-Medicaid payment. Moreover, beneficiaries acquired greater dosages of dispensed opioids from both Medicaid and non-Medicaid payment sources during lock-in and post-release. Refining LIPs to increase beneficiary access to substance use disorder screening and treatment services and provider use of PDMPs may address important unintended consequences.

Duke Scholars

Author Asheley Cockrell Skinner Population Health Sciences