In North Carolina, Medicaid enrollees circumvent a controlled substance lock-in program
In North Carolina, Medicaid enrollees circumvent a controlled substance lock-in program

Andrew RobertsControlled substance lock-in programs which require patients at high risk for prescription drug abuse to visit a single doctor and pharmacy for opioid prescription coverage are an increasingly popular policy solution to the epidemic of opioid misuse. But a new Creighton University study suggests a significant loophole in the program may limit its effectiveness.

“Lock-in programs are really good at cost containment,” says Andrew Roberts, assistant professor of pharmacy sciences at Creighton University. “But there are a lot of questions as to how useful they are in the  prevention of opioid abuse because of a major loophole: Patients who are locked-in can completely circumvent the program’s restrictions by paying full price for their prescription out-of-pocket.”

Roberts, with colleagues from the University of North Carolina at Chapel Hill, conducted a retrospective cohort study of 1,647 enrollees of North Carolina’s Medicaid program from October 2009 through September 2012, using a dataset that linked the state’s Medicaid claims data with records from the state’s prescription drug monitoring program.

According to the study, published Oct. 4, 2016 in Health Affairs, the  estimated probability that enrollees would circumvent their Medicaid coverage at least once in a given month to purchase an opioid out-of-pocket was 55 percent following lock-in enrollment, compared to 16 percent before the restrictions took effect.

“Essentially, we found that once enrollees were locked-in they were almost four times as likely to pay for prescriptions entirely out of pocket,” says Roberts. “The number of cash-pay opioid prescriptions also about quadrupled.”

Though the North Carolina Medicaid lock-in program drastically reduced the number of Medicaid-covered opioid claims, when accounting for the prescription drug monitoring program data, the out-of-pocket purchases offset about 50 percent of that reduction.

“There’s a lot of momentum behind very broad use of these kinds of controlled substance lock-in programs,” says Roberts. “But we know very little about how they affect patient behaviors. Our study provides some of the first rigorous evidence that they may not be as effective as we’d hoped.”