PROJECT SUMMARY/ABSTRACT One strategy in the battle against the opioid crisis in the United States is to promote safer prescribing for opioid analgesics, but evidence on safer prescribing for acute painful conditions is lacking. This F31 dissertation project will investigate the longer-term (up to 180 days) risks of prescribing opioid analgesics at emergency department (ED) discharge. The project involves using rich, longitudinal data from a group of adult patients presenting to 15 geographically-diverse EDs throughout the United States with suspected acute renal colic. Ms. Anna Wentz, epidemiology doctoral student at Brown University, will conduct this secondary analysis using data already available to her use from the Study of Tomography Of Nephrolithiasis Evaluation, or STONE trial (R01HS019312, ClinicalTrials.gov: NCT01451931). The resultant manuscripts from these analyses will form the basis of Ms. Wentz’s doctoral dissertation. Support from this F31 grant will enable Ms. Wentz to complete this project of high public health significance, which will provide her with the necessary training and credentials to pursue a post-doctoral training position following her graduation from Brown University. She ultimately plans to become an independent academic researcher examining the impact of opioid and alternative analgesics on acute pain and substance use epidemiology. Ms. Wentz will use the STONE trial sample of 2,759 adult emergency department patients with suspected acute renal colic to determine: (Aim 1) the demographic, clinical, and institution-level factors that predict whether a patient with suspected renal colic was prescribed an opioid or no opioid analgesic at ED discharge; (Aim 2) if pain persisted longer for suspected acute renal colic patients prescribed an opioid vs. no opioid analgesic at ED discharge, taking into account predictors of prescription identified in Aim 1; and (Aim 3) if opioid analgesic use persisted longer for suspected acute renal colic patients prescribed opioid vs. no opioid analgesics at ED discharge, taking account predictors of prescription and pain persistence identified in Aims 1 and 2. To guide safer opioid analgesic prescribing and limit the potential for opioid abuse, healthcare providers and policymakers need evidence of the effects (or lack thereof) of opioid analgesics on persistent pain and duration of their use. If our hypotheses are correct, this F31 project can provide the first evidence of the effects of opioid analgesics on persistent pain and duration of analgesic use among patients with acute renal colic, as well as the potential for opioid analgesic-associated transition from acute to chronic pain.