Project Summary/Abstract Injured workers with chronic pain have been exposed to dramatic increases in high-dose opioid prescriptions, which have in turn been associated with increasing mortality, work disability, and catastrophic workers' compensation (WC) costs. In 2007, Washington was the first state to implement an opioid guideline with a high-dose threshold, and several other states have since followed suit. State-level opioid prescribing guidelines offer promise in achieving prevention goals, but there has been little systematic evaluation. There are significant knowledge gaps with respect to (1) the prevalence of opioid-related morbidity specifically among injured workers, and (2) opioid policy effectiveness in WC settings. The objective of this study is to quantify the burden of opioid-related morbidity among injured workers, and to demonstrate whether high-dose prescribing guidelines provide a path toward improved worker health outcomes. The central hypothesis is that guidelines that include a component focused on high-dose prescribing practices have had a significant beneficial impact on trends in hospitalizations for opioid poisonings and adverse effects among injured workers. Population- based hospital discharge data for 8 states will be used to assess two specific aims. Aim 1: Quantify the burden of inpatient hospitalizations due to opioid poisoning and opioid adverse effects among workers, and describe demographics. Aim 2: Determine whether trends in the rates of opioid-related morbidity among workers changed after implementation of opioid prescribing guidelines with a high-dose component. To address these aims, rates and trends will be estimated from 2003 through 2014 for 8 states. Staggered implementation of opioid guidelines across multiple states sets the stage for a natural experiment. A multiple baseline interrupted time series design with multiple concurrent comparator states will be used to assess the effect of opioid guidelines on trends in opioid morbidity. These aims are expected to produce several useful outcomes. Aim 1 will document the prevalence of opioid-related morbidity among injured workers that can be used to motivate and support investment in policy changes and prevention opportunities. Aim 2 will provide evidence regarding the effectiveness of a specific policy approach. This study will contribute to R2P by providing state health departments and WC agencies with evidence to support policy changes to protect worker health. This study is innovative because it will be the first study to evaluate the effects of opioid prescribing guidelines on outcomes for injured workers using hospital discharge data for multiple states. It is significant because it will fill important knowledge gaps regarding opioid-related morbidity among injured workers and will support implementation of effective policies targeted at stemming the rising tide of prescription opioid-related morbidity that constitutes an unacceptable and preventable iatrogenic burden on injured workers, WC systems, and society at large.