Impact of Hurricane Florence on buprenorphine transactions for opioid use disorder: A dual-perspective synthetic control study.

Background: The opioid epidemic is a major public health crisis in the United States, with buprenorphine serving as a critical medication-assisted treatment for opioid use disorder. Timely and consistent access to buprenorphine is essential for sustaining recovery and preventing relapse, yet how environmental disruptions affect treatment access remains poorly understood. Methods: We analyzed buprenorphine transaction data from IQVIA healthcare data analytics platform (formerly IMS Health and Quintiles) in North Carolina aggregated by patient residence and pharmacy location to the three-digit ZIP code (ZIP3) level from April to October 2018. Using generalized synthetic control methods, we estimated the causal effect of Hurricane Florence on transaction rates in ZIP3 284, encompassing southeastern coastal North Carolina areas severely affected by the hurricane, with streamflow data capturing flooding conditions. Results: Hurricane Florence substantially disrupted buprenorphine access. Transaction counts aggregated by patient residential ZIP code showed a 13.8% decrease in transactions at evacuation week, with effects persisting but showing some recovery over time. Transaction counts aggregated by pharmacy location ZIP codes experienced more severe and sustained impacts, with a 21.9% decrease in transaction activity at evacuation week and lesser recovery throughout the post-hurricane period compared to patient data. Conclusion: Patient- and pharmacy-level data revealed distinct patterns of disaster-related treatment disruption with implications for emergency preparedness. Analyses based only on patient data would have underestimated the hurricane's impact, suggesting patients-maintained access through mobility while local treatment infrastructure faced sustained challenges.