LAUSR

BACKGROUND AND AIMS The time lag encountered when accessing health care data is one major barrier to implementing opioid overdose prediction measures in practice. Little is known regarding how one's opioid overdose risk changes over time. We aimed to identify longitudinal patterns of individual predicted overdose risks among Medicaid beneficiaries after initiation of opioid prescriptions. DESIGN A retrospective cohort study. SETTING Pennsylvania, USA. PARTICIPANTS Pennsylvania Medicaid beneficiaries aged 18 to 64 years who initiated opioid prescriptions between July 2017 and September 2018 (318,585 eligible beneficiaries (mean age=39±12 years, female=66%, White=62% and Black=25%), MEASUREMENTS: We first applied a previously developed and validated machine-learning algorithm to obtain risk scores for opioid overdose emergency room or hospital visits in 3-month intervals for each beneficiary who initiated opioid therapy, until disenrollment from Medicaid, death, or the end of observation (December 2018). We performed group-based trajectory modeling to identify trajectories of these predicted overdose risk scores over time. FINDINGS Among eligible beneficiaries, 0.61% had ≥1 occurrences of opioid overdose in a median follow-up of 15 months. We identified five unique opioid overdose risk trajectories: three trajectories (accounting for 92% of the cohort) had consistent overdose risk over time including consistent-low risk (63%), consistent-medium risk (25%), and consistent-high risk (4%) groups; another two trajectories (accounting for 8%) had overdose risks that substantially changed over time, including a group that transitioned from high to medium risk (3%) and another group that increased from medium to high risk over time (5%). CONCLUSIONS Over 90% of Medicaid beneficiaries in Pennsylvania USA with one or more opioid prescriptions had consistent, predicted opioid overdose risks over 15 months. Applying opioid prediction algorithms developed from historical data may not be a major barrier to implementation in practice for the large majority of individuals.