How do restrictions on opioid prescribing, harm reduction, and treatment coverage policies relate to opioid overdose deaths in the United States in 2013-2020? An application of a new state opioid policy scale.

Background: Identifying the most effective state laws and provisions to reduce opioid overdose deaths remains critical.

Methods: Using expert ratings of opioid laws, we developed annual state scores for three domains: opioid prescribing restrictions, harm reduction, and Medicaid treatment coverage. We modeled associations of state opioid policy domain scores with opioid-involved overdose death counts in 3133 counties, and among racial/ethnic subgroups in 1485 counties (2013-2020). We modeled a second set of domain scores based solely on experts' highest 20 ranked provisions to compare with the all-provisions model.

Results: From 2013 to 2020, moving from non- to full enactment of harm reduction domain laws (i.e., 0 to 1 in domain score) was associated with reduced county-level relative risk (RR) of opioid overdose death in the subsequent year (adjusted RR = 0.84, 95 % credible interval (CrI): 0.77, 0.92). Moving from non- to full enactment of opioid prescribing restrictions and Medicaid treatment coverage domains was associated with higher overdose in 2013-2016 (aRR 1.69 (1.35, 2.11) and aRR 1.20 (1.11, 1.29) respectively); both shifted to the null in 2017-2020. Effect sizes and direction were similar across racial/ethnic groups. Results for experts' highest 20 ranked provisions did not differ from the all-provision model.

Conclusions: More robust state harm reduction policy scores were associated with reduced overdose risk, adjusting for other policy domains. Harmful associations with opioid prescribing restrictions in 2013-2016 may reflect early unintended consequences of these laws. Medicaid coverage domain findings did not align with experts' perceptions, though data limitations precluded inclusion of several highly ranked Medicaid policies.