Establishing an Evidence Base to Increase the Utility of Urine Drug Testing in Opioid Use Disorder Treatment. - Project Summary/Abstract Urine drug testing (UDT) is an integral component of opioid use disorder (OUD) treatment, and is often required by payers for patients treated with medications for OUD (MOUD). These regulations exist despite a lack of evidence-based guidelines. There is no consensus about the optimal UDT frequency, what drugs to test for, when to use different types of tests (e.g., presumptive versus definitive), and how to adapt care when patients test positive for non-prescribed substances. Inconsistent practices have important public health and clinical implications, as they can contribute to either missed opportunities to improve care or to the misallocation of clinical resources. The goal of this grant is to identify variation in real-world use of UDT that can be modified by clinical guidelines and policy change, and to examine the patient- and clinician-level factors that influence the application of UDT, and their relationship with processes of care. Aim 1 will characterize distinct trajectories of UDT use during episodes of OUD treatment nationally, and across patient characteristics, clinicians, payers, and states. The sample will comprise continuously enrolled patients with diagnosed OUD from 2015-2022 from a national, multi-payer database that tracks patients across disparate data systems and includes service claims data linked to laboratory results. We will examine the correlates of testing frequency and type across different groups of interest. Aim 2 will identify distinct trajectories of drug positivity during OUD treatment episodes and identify variation across groups. We will identify the prevalence of patients testing positive for common non- prescribed drugs (e.g., opioids, cocaine) at the beginning of treatment episodes and the persistence of positivity in the treatment episode. Using latent class analysis, we will group patients into subtypes related to patterns of drug positivity (e.g., persistently abstinent, transitioning to abstinence, persistently positive). Aim 3 will estimate the association between trajectories of UDT use, substance positivity, and process of care measures in the episode (e.g., retention, MOUD adherence, hospitalization). Using Aims 1-2 variables, we hypothesize that greater UDT use will not generally lead to changes in process of care outcomes and that patients who are persistently positive for substances will have worse process of care outcomes. Aim 4 will examine perspectives of clinicians to identify perceptions and practices related to UDT use. We will survey a national sample of clinicians treating OUD recruited from a drug testing laboratory. They will be asked about their knowledge, attitudes, and practices related to testing. From this group, we will conduct qualitative interviews with 30 clinicians who vary in their testing practices to learn more about potential opportunities to inform decision- making surrounding UDT in clinical practice. Overall, this study will characterize the variation in UDT use in real- world clinical practice and help identify the potential scope for UDT to positively change processes of care for patients. The findings will lay the foundation for developing pragmatic clinical trials, informing policy decisions, and refining clinical practice.