Assessing Sustained and Differential Impacts of North Carolina’s Medicaid "Lock-In" Program

Abstract

Between 2000 and 2015, half a million people died from a drug overdose in the U.S., and most of these deaths involved an opioid. Medicaid beneficiaries are a particularly high-risk population. One strategy that nearly all states use to address potential misuse of prescription opioids, and other controlled substances (CS), are Medicaid “lock-in” programs (MLIPs). MLIPs identify beneficiaries demonstrating potential overutilization of CS and control their access. In North Carolina (NC), beneficiaries enrolled in the MLIP are required to use a single prescriber and pharmacy to obtain specific CS for a 12-month period. There has been little research examining the impact of MLIPs. In this dissertation, we 1) examined the sustained impact of the NC MLIP on dispensed CS and dosages of opioids dispensed (in terms of morphine milligram equivalents (MMEs)) and 2) examined whether trajectories of MMEs differed across time prior to, during, and following release from the MLIP for different strata of the population. Data included NC Medicaid claims linked to records from NC’s Prescription Drug Monitoring Program from October 2009 through June 2013. We found that compared to a period of stable CS dispensing prior to MLIP enrollment, the MLIP reduced the average numbers of CS dispensed both during lock-in and following release. However, the program was also associated with increased acquisition of dispensed CS using non-Medicaid payment (e.g., out-of-pocket) both during lock-in and following release. Moreover, beneficiaries acquired greater MMEs of dispensed opioids from both Medicaid and non-Medicaid payment sources during lock-in and following release. Considerable heterogeneity existed in trajectories of MMEs of dispensed opioids across time prior to, during, and following release from the MLIP. Five trajectory patterns appeared to sufficiently describe this underlying heterogeneity. All patterns demonstrated a spike in MMEs in the six months prior to lock-in, constituting a trigger for MLIP enrollment; however, patterns were dissimilar in overall starting values and slopes. While the trajectories indicated that the MLIP may have had little influence on MME patterns across time, strong associations between trajectory patterns and beneficiary characteristics were evident. Findings from this dissertation thus provide a foundation for informing future MLIP improvements.Doctor of Philosoph