Impact of Marijuana Legalization on Opioid Utilization in Patients Diagnosed with Pain

Abstract

Background: Given efforts to reduce opioid use, and because marijuana potentially offers a lower-risk alternative for treating chronic pain, there is interest in understanding the public health impact of marijuana legalization on opioid-related outcomes. Objective: Assess the impact of recreational and medical marijuana legalization on opioid utilization among patients receiving pharmacotherapy for pain. Design: Retrospective claims-based study of commercially insured patients continuously eligible for pharmacy and medical benefits from July 8, 2014 to June 30, 2017. Index pain prescription period was defined between January 8, 2015 and June 30, 2015, and longer-term opioid use examined during 2-year follow-up. Marijuana state policy on July 1, 2015, was assigned: none; medical only; or medical and recreational. Participants: Patients aged 18–62 without cancer diagnosis. Main Measures: Patient receiving (1) opioid at index; (2) > 7 days’ supply of index opioid; (3) opioid during follow-up; and (4) ≥ 90 days’ opioid supply during follow-up. Multivariable regression assessed associations between opioid utilization and state marijuana policy, adjusting for age, gender, overall disease burden, mental health treatment, concomitant use of benzodiazepine or muscle relaxant, and previous pain prescription. Key Results: Of 141,711 patients, 80,955 (57.1%) resided in states with no policy; 56,494 (39.9%) with medical-only; and 4262 (3.0%) with medical and recreational. Patients in states with both policies were more likely to receive an index opioid (aOR = 1.72, 95% CI = 1.61–1.85; aOR = 1.90, 95% CI = 1.77–2.03; P < 0.001) but less likely to receive > 7 days’ index supply (aOR = 0.84, 95% CI = 0.77–0.91; aOR = 0.76, 95% CI = 0.70–0.83; P < 0.001) than patients in states with no policy or medical-only, respectively. Those in states with both policies were more likely to receive a follow-up opioid (aOR = 1.87, 95% CI = 1.71–2.05; aOR = 2.20, 95% CI = 2.01–2.42; P < 0.001) than those in states with no policy or medical-only, respectively, and more likely to receive ≥ 90 cumulative follow-up opioid days’ supply (aOR = 1.18, 95% CI = 1.07–1.29; P < 0.001) than those in states with no policy. Conclusions: Our analysis does not support the supposition that access to marijuana lowers use of chronic opioids for pain.