Impact of California's naloxone co-prescription law on emergency department visits, 30-day mortality, and prescription patterns

ObjectiveOpioid overdose is a public health epidemic adversely impacting individuals and communities. To combat this, California passed a law mandating that prescribers offer a naloxone prescription in certain circumstances. Our objective was to evaluate associations with California's naloxone prescription mandate and emergency department (ED) overdose visits/hospitalizations, opioid and naloxone prescribing, and 30-day mortality. MethodsThis retrospective cohort study included data from January 1, 2018, to December 31, 2019, and included all Kaiser Permanente Southern California (KPSC) members aged >10 years across 15 KPSC EDs. Exposure was defined as presentation to the ED within the study period. The primary outcome was ED visits for opioid overdose pre- and post-implementation of California's naloxone prescription mandate. ResultsA total of 1.1 million ED visits (534K pre/576K post) were included in the study population. ED opioid overdose visits were 344 (6.4/10,000) pre-policy and 351 (6.1/10,000) post-policy implementation, while non-opioid overdose visits were 309 (5.8/10,000) pre-implementation and 411 (7.1/10,000) post-implementation. The unadjusted rate of visits with opioid prescriptions decreased significantly (14.9% pre to 13.5% post) after implementation. ED naloxone prescriptions increased substantially (104 pre vs. 6031 post). Primary adjusted interrupted time series analysis found no statistical difference between monthly opioid overdose visits pre versus post (odds ratio 1.02, 95% confidence interval [CI] 0.98-1.07). Difference-in-differences analysis revealed no significant changes in hospitalization (coefficient [CE] = -0.05, 95% CI = -0.11 to 0.02) or 30-day mortality (CE = -0.01, 95% CI = -0.03 to 0.01). ConclusionThis study revealed that the implementation of California's naloxone prescription mandate was associated with significantly increased naloxone prescribing and decreased opioid prescribing, but no significant change in ED opioid overdose visits, hospitalizations, or 30-day mortality. This indicates that increasing naloxone prescribing alone may not be sufficient to lower opioid overdose rates.