Association of buprenorphine retention and subsequent adverse outcomes following non-fatal overdose: An analysis using statewide linked Maryland databases

Introduction: Patients receiving buprenorphine after a non-fatal overdose have lower risk of future nonfatal or fatal overdose, but less is known about the relationship between buprenorphine retention and the risk of adverse outcomes in the post-overdose year. Objective: To examine the relationship between the total number of months with an active buprenorphine prescription (retention) and the odds of an adverse outcome within the 12 months following an index non-fatal overdose. Materials and methods: We studied a cohort of people with an index non-fatal opioid overdose in Maryland between July 2016 and December 2020 and at least one filled buprenorphine prescription in the 12-month post-overdose observation period. We used individually linked Maryland prescription drug and hospital admissions data. Multivariable logistic regression models were used to examine buprenorphine retention and associated odds of experiencing a second non-fatal overdose, all-cause emergency department visits, and all-cause hospitalizations. Results: Of 5439 people, 25% (n=1360) experienced a second non-fatal overdose, 78% had an (n=4225) emergency department visit, and 37% (n=2032) were hospitalized. With each additional month of buprenorphine, the odds of experiencing another non-fatal overdose decreased by 4.7%, all-cause emergency department visits by 5.3%, and all-cause hospitalization decreased by 3.9% (p<.0001, respectively). Buprenorphine retention for at least nine months was a critical threshold for reducing overdose risk versus shorter buprenorphine retention. Conclusions: Buprenorphine retention following an index non-fatal overdose event significantly decreases the risk of future overdose, emergency department use, and hospitalization even among people already on buprenorphine.