Receipt of opioid use disorder treatments prior to fatal overdoses and comparison to no treatment in Connecticut, 2016-17.

Objective: To determine the relative risk of death following exposure to treatments for OUD compared to no treatment.

Methods: In this retrospective cohort study we compiled and merged state agency data on accidental and undetermined opioid overdose deaths in 2017 and exposures to OUD treatment in the prior six months to determine incidence rates following exposure to different treatment modalities. These rates were compared to the estimated incidence among those exposed to no treatment to determine relative risk of death for each treatment exposure.

Results: Incidence rates for opioid poisoning deaths for those exposed to treatment ranged from 6.06±1.40 per 1000 persons exposed to methadone to 17.36±3.22 per 1000 persons exposed to any non-medication treatment. The estimated incidence rate for those not exposed to treatment was 9.80±0.72 per 1000 persons. With no exposure to treatment as referent, exposure to methadone or buprenorphine reduced the relative risk by 38% or 34%, respectively; the relative risk of non-medication treatments was equal to or worse than no exposure to treatment (RR = 1.27-1.77).

Principal Conclusions: Exposure to non-MOUD treatments provided no protection against fatal opioid poisoning whereas the relative risk was reduced following exposures to MOUD treatment, even if treatment was not continued. Population level efforts to reduce opioid overdose deaths need to focus on expanding access to agonist-based MOUD treatments and are unlikely to succeed if access to non-MOUD treatments is made more available.