Impact of a drug utilization review program on high-risk use of prescription controlled substances.

BACKGROUND: Prescription drug abuse has prompted considerable concern. We evaluated a retrospective drug utilization review program to reduce controlled substance use among individuals with high-risk utilization.
METHODS: We analyzed pharmacy claims from a large pharmaceutical benefits manager. For each eligible member, we calculated a controlled substance score based on the number and type of claims, prescribers and pharmacies, and utilization patterns over three months. Two state health plans sent controlled substance letters to prescribers of members meeting or exceeding a plan- and pre-specified controlled substance score. Two different state health plans did not send such letters. We used a difference-in-difference design and generalized estimating equations to quantify the impact of the program on the mean difference in reduction of the controlled substance score over six months.
RESULTS: Eligible members in the intervention and comparison states had similar baseline mean controlled substance scores (19.0 vs. 18.6, p = 0.36). Adjusting for individuals' age, sex and pharmacy risk group score, reductions in the mean controlled substance score were greater in the intervention than comparison cohort (5.67 vs. 4.31, p = 0.01), corresponding with a 34.0% reduction in the intervention cohort compared to a 25.5% reduction in the comparison cohort. Changes were driven primarily by reductions in the number of controlled substance claims filled (30.5% vs. 23.1%, p = 0.01), as well as by a non-statistically significant trend towards reductions in the number of prescribers and pharmacies used (26.9% vs. 20.1%, p = 0.07).
CONCLUSIONS: Retrospective drug utilization review programs may reduce controlled substance scores and claims among individuals with patterns suggesting high-risk utilization.