Initial Treatment for Acute Low Back Pain and Risk of Opioid Use Disorder and Overdose.

Importance: Guideline-discordant care for acute low back pain (aLBP) is common and has been associated with adverse outcomes. Objectives: To estimate the incidence of new opioid use disorder (OUD) or overdose diagnosis among opioid-naive patients with Medicaid coverage initiating treatment for aLBP and to evaluate the association between initial treatment modalities and subsequent risk of OUD or overdose diagnosis. Design, Setting, and Participants: This retrospective cohort study used data from January 1, 2016, to December 31, 2019, with 13 months of follow-up (1-month exposure assessment followed by 12 months of outcome follow-up) from the Transformed Medicaid Statistical Information System Analytic Files from 25 states that expanded Medicaid under the Patient Protection and Affordable Care Act by 2014. Participants included opioid-naive, adults aged less than 65 years who received pain treatment within 1 month of diagnosis of aLBP. Data were analyzed from March 1, 2025, to July 31, 2026. Exposures: Initial pharmacologic and nonpharmacologic treatments for aLBP. Main Outcomes and Measures: OUD or overdose diagnosis, defined using diagnostic codes for opioid abuse, opioid dependence, opioid-involved overdose, or a prescription for medication for treating OUD. Results: In this cohort of  399 500 Medicaid patients who initiated treatment for newly diagnosed aLBP, the median age was 39 (IQR, 30-50) years, and 237 846 (59.5%) were female. The cumulative incidence of OUD or overdose diagnosis was 1.4% at 7 months and 2.3% at 13 months. Initiating vs not initiating higher-dose opioids (>50 mg of morphine equivalent) as part of the initial treatment was associated with the greatest risk, increasing risk of OUD or overdose by 146.6% (95% CI, 121.5%-171.7%). Initiating vs not initiating lower-dose opioids prescribed for more than 7 days or gabapentinoids each increased risk by 105.2% (95% CI, 89.0%-121.4%) and 101.6% (95% CI, 84.9%-118.2%), respectively. Nonpharmacologic, noninterventional therapies were associated with reductions in risk of OUD or overdose diagnosis. Initiating vs not initiating chiropractic care was associated with the largest relative risk reduction, decreasing risk by 32.8% (95% CI, 26.8%-38.9%), and initiating physical therapy was associated with 31.1% decreased risk (95% CI, 22.1%-40.1%). Conclusions and Relevance: In this cohort study, nonpharmacologic, noninterventional treatment was associated with reductions in risk of OUD or overdose diagnosis while initiating treatment with opioids or gabapentinoids was each associated with higher risks. These results support guideline recommendations favoring nonpharmacologic treatments as first-line therapy for aLBP.