War on opioid abuse! Evaluating prescription drug monitoring programs - A comparitive study of Indiana and Kentucky

Opioids abuse and misuse have become an epidemic in the United States. Over 200 million opioid prescriptions were written in 2013. These have been linked to an increasing proportion of the more than 2 million Americans suffering from prescriptions opioids substance use disorders and fatal overdose. Since 2007, several states have begun to address inappropriate opioids prescribing through regulations and policies. This study evaluates the success of one such representative prescription drug monitoring program  using data from the states of Indiana and Kentucky. Indiana ranked 9th in the US for prescribing opioid pain relievers and legislators issued new prescribing rules on December 15, 2013 requiring physicians to:  1) evaluate opioid recipients for psychiatric conditions, 2) review the patients' drug prescription history in INSPECT, Indiana's prescription drug monitoring program, 3) perform regular drug screens, and 4) require that patients sign a controlled-substance agreement (5). Using the population of all opiod drug prescriptions over a period of three years surrounding the change in prescription guidelines we evaluate whether the new drug prescription monitoring program has caused a reduction in the volume of dispensed narcrotics. Moreover, we try to pin down subpopulations most impacted by the policy. Results from a difference-in-difference study comparing Indiana to the control state of Kentucky we find that the policy led to a significant decline in opiods dispensed, a decrease which was greater for male patients of lower socioeconomic status. Considering mediators we find that the reduction in total volume of opioid anelgesics is driven by decrease in days of supply and the number of refills given. Moreover, the reduction in opioid prescriptions is driven by reduction in high dosage prescriptions which raises concerns about the potential adverse effect of the policy on pain management.