One-Year Mortality and Associated Factors in Patients Receiving Out-of-Hospital Naloxone for Presumed Opioid Overdose

Study objective: Out-of-hospital naloxone has been championed as a lifesaving solution during the opioid epidemic. However, the long-term outcomes of out-of-hospital naloxone recipients are unknown. The objectives of this study are to describe the 1-year mortality of presumed opioid overdose victims identified by receiving out-of-hospital naloxone and to determine which patient factors are associated with subsequent mortality. Methods: This was a regional retrospective cohort study of out-of-hospital records from 7 North Carolina counties from January 1, 2015 to February 28, 2017. Patients who received out-of-hospital naloxone were included. Out-of-hospital providers subjectively assessed patients for improvement after administering naloxone. Naloxone recipients were cross-referenced with the North Carolina death index to examine mortality at days 0, 1, 30, and 365. Naloxone recipient mortality was compared with the age-adjusted, at-large population's mortality rate in 2017. Generalized estimating equations and Cox proportional hazards models were used to assess for mortality-associated factors. Results: Of 3,085 out-of-hospital naloxone encounters, 72.7% of patients (n=2,244) improved, whereas 27.3% (n=841) had no improvement with naloxone. At day 365, 12.0% (n=269) of the improved subgroup, 22.6% (n=190) of the no improvement subgroup, and 14.9% (n=459) of the whole population were dead. Naloxone recipients who improved were 13.2 times (95% confidence interval 13.0 to 13.3) more likely to be dead at 1 year than a member of the general populace after age adjusting of the at-large population to match this study population. Older age and being black were associated with 1-year mortality, whereas sex and multiple overdoses were not. Conclusion: Opioid overdose identified by receiving out-of-hospital naloxone with clinical improvement carries a 13-fold increase in mortality compared to the general population. This suggests that this is a high-risk population that deserves attention from public health officials, policymakers, and health care providers in regard to the development of long-term solutions.