Patient Outcomes in a Medicaid Managed Care Lock-In Program

Prescription drug abuse is a growing epidemic in the United States, and opioids are among the most commonly abused and misused controlled substances. Managed care organizations can use pharmacy lock-in programs to limit patients' access to opioids by requiring that they receive all scripts from 1 prescriber, potentially reducing inappropriate use.

To evaluate opioid use patterns among patients in a Medicaid managed care lock-in program limiting opioid coverage to prescriptions written by assigned prescribers.

This retrospective cohort study included all patients enrolled in the lock-in program at Blue Care Network (BCN) of Michigan Medicaid managed care from March 2008 through May 2013, with outcomes assessed through August 2013. BCN medical and pharmacy claims, the Michigan Automated Prescription System, and Blue Cross Complete Controlled Substance Committee reports were used to assess outcomes at 6, 12, 24, and 36 months after enrollment. Patients were defined as "stable" if they exclusively filled opioid prescriptions from assigned prescribers or received treatment for opioid dependence and "unstable" if they purchased prescription opioids with cash or submitted opioid claims not prescribed by assigned providers.

Of the 59 patients enrolled in the program, over half (55.9%) dropped BCN coverage, and 1 died while enrolled. The proportion of patients who dropped coverage fell as time in the program increased, from 29% in the first 6 months to 11% semiannually after 24 months. Among those who remained enrolled, the proportion of stable patients increased from 31% at 6 months to 78% at 36 months. The small sample size did not permit formal statistical analysis.

The finding that most patients exited the program by dropping coverage was an unintended consequence meriting further investigation. Conversely, the finding that patients who remained enrolled largely achieved desired outcomes indicates that this program played an important role in addressing opioid abuse.