Price elasticity of demand for new and recurring opioid prescriptions

Objective: Several U.S. states have recently enacted excise taxes to curb prescription opioid use and other states are considering similar measures. We assessed the effects of increasing out-of-pocket costs (OPC) on new and recurring opioid fills. Methods: We conducted a retrospective cohort study of opioid-naive individuals presenting with acute back pain using data from a nationwide claims repository. We estimated the effect of OPC on the initiation of opioid treatment in logistic regressions, controlling for socio-demographics, medical history, healthcare utilization, insurance type, and region. With the same covariates plus morphine milligram equivalents and days supplied, we estimated the effect of OPC on the number of opioid fills in negative binomial regressions. We report the price elasticity of demand (PED) for prescription opioids, defined as the percentage change in outcome resulting from a two-fold increase in OPC. Results: Of 25,531 adults diagnosed with acute back pain in Q1 of 2018, 2,451 (9.6%) filled at least one opioid prescription. In multivariable regression, the association between OPC and initiating opioid treatment was not significant (PED= -1.9%; 95% CI: -5.5%, 1.7%). However, by region, the PED was -10.3% (95% CI: -18.1%, -2.4%) in the coastal states and 1.6% (95% CI: -2.5%, 5.7%) in the central-southern states. The PED for the number of prescription fills was -3.7% (95% CI: -7.3%, -0.1%), which also differed by region. In the coastal states, the PED was -15.2% (95% CI: -24.7%, -5.7%) and in the central-southern states -1.5% (95% CI: -5.4%, 2.4%). Conclusions: Opioid fills were price sensitive in the coastal states but not in the central-southern states. Policies that would increase OPC might have a restraining effect on opioid consumption in parts, but not all of the U.S.