Opioid Overdose Mortality Among Patients Receiving a Peer-Delivered, Emergency Department-Based Nonfatal Opioid Overdose Intervention in New York City, 2017-2022.

Objectives. To measure risk of fatal opioid overdose within 1 year of engagement with Relay's nonfatal overdose response initiative and characterize differences in demographics, substance use, and overdose risk factors by service engagement. Methods. We assessed the mortality status of 5006 patients who presented to Relay's partnered emergency departments (EDs) in New York City for a suspected nonfatal opioid overdose (2017-2022) and accepted peer-delivered overdose prevention services in the ED, grouped by agreement to and subsequent receipt of post-ED follow-up. Results. Compared with those declining follow-up, the risk of fatal overdose was not significantly higher among those consenting (adjusted hazard ratio [AHR] = 1.24; 95% confidence interval [CI] = 0.94, 1.65). Among those accepting follow-up, risk was lower for those who were reached (AHR = 0.64; 95% CI = 0.48, 0.84) compared with those who were not. Conclusions. Peer-delivered ED interventions such as Relay may be effective in reducing fatal overdose risk for individuals with fewer risk factors, and post-ED services are essential for those at higher risk. Approaches should be tailored to more effectively deliver post-ED services to this group. (Am J Public Health. 2026;116(1):113-123. https://doi.org/10.2105/AJPH.2025.308270).