Report Released on Sustained Effects of North Carolina’s Medicaid “lock-in” Program on Prescription Drugs


  • NC Medicaid “lock-in” program appeared to reduce numbers of controlled substances (e.g., painkillers) dispensed
  • Reductions were evident both while patients were enrolled in the program and in year following program release
  • Dosages of opioids (in terms of morphine milligram equivalents) increased while patients were enrolled in the program and following release
  • Use of cash payment increased during lock-in and after release

(Chapel Hill, N.C. November 14, 2017) – A new study examined the immediate and sustained effects of North Carolina’s Medicaid “lock-in” program on the amounts of prescriptions drugs dispensed to those enrolled in the program.

Rebecca Naumann, MSPH, graduate research assistant with the Injury Prevention Research Center and a doctoral student in the Department of Epidemiology in the UNC Gillings School of Global Public Health, is first author of the study. Other co-authors included Dr. Stephen Marshall, Dr. Jennifer Lund, Dr. Nisha Gottfredson, Dr. Christopher Ringwalt, and Dr. Asheley Skinner.

The full article on their findings, titled “Evaluating short- and long-term impacts of a Medicaid ‘lock-in’ program on opioid and benzodiazepine prescriptions dispensed to beneficiaries,” was published online November 14, 2017 in the journal Drug and Alcohol Dependence.

Insurance-based “lock-in” programs have become an increasingly popular strategy to address the potential overutilization of controlled substance prescriptions, such as opioids (painkillers) and benzodiazepines (anti-anxiety drugs). “Lock-in” programs typically require patients to use a single prescriber and/or pharmacy to obtain certain controlled substance prescriptions (e.g., opioids, benzodiazepines) for a specified period of time. Naumann and her colleagues examined the specific impacts of North Carolina’s Medicaid “lock-in” program on the amounts of these prescriptions obtained.

Researchers followed a cohort of adults enrolled in the “lock-in” program in the first two years of its operation (October 2010-September 2012). They analyzed patients’ Medicaid claims linked to their Prescription Drug Monitoring Program (PDMP) records to gain a more complete understanding of all opioids and benzodiazepines dispensed to “lock-in” program patients. This unique linkage allowed Naumann and her colleagues to not only examine the number of opioids and benzodiazepines acquired by patients through Medicaid, but also those acquired using other sources of payment, such as cash.

Among the findings, it appeared that the program did reduce the average number of controlled substances dispensed during and after the patient’s “lock-in.” At the same time, the researchers found that the dosage of opioids (in terms of morphine milligram equivalents) increased during and after their “lock-in” period. Some participants in the program increased their purchase of controlled substances outside of Medicaid, paying cash for these prescriptions during their “lock-in” period and after release.

“While it’s important to see that the program reduced the average number of controlled substances dispensed during lock-in and following program release, it’s also important to note that patients acquired more controlled substances using cash payment,” said Naumann. “The increase in cash payment could be related to a number of factors, but overall signals an important need for improved care coordination in this population.”

These findings highlight the need for providers to regularly check the state’s PDMP database in order to obtain a complete picture of all controlled substances dispensed to patients. Naumann also noted that designing or modifying these programs to increase patient’s accessibility to substance use disorder treatment and treatment for other comorbid conditions, such as mental health disorders, may improve patient outcomes.

“Our understanding of the impacts of these programs has generally been limited to understanding changes in healthcare utilization and costs from an insurer perspective,” said Naumann. “This research sought to provide a more complete understanding of program effects on the magnitude of prescriptions dispensed from a patient perspective. In working to address the opioid crisis, it is critical that we gain a full understanding of the effects of opioid-related policies and programs so that we can design and implement interventions that have the greatest public health impact.”