High Risk of Mortality in the Week Following a Non-fatal Opioid Overdose

Patients with opioid use disorder have an increased risk of overdose. This prospective observational study in Oslo, Norway aimed to assess subsequent all-cause mortality in patients 18–70 years of age following receipt of naloxone from emergency medical services (EMS) for an opioid overdose from 2014 to 2018.

• The cohort included 890 people (76 percent male, mean age 38) treated for 1764 overdoses (3142 person-years).
• Overall, 112 people (13 percent) died during the study period; none within two days of the index non-fatal overdose. The most common cause of death was overdose (53 percent).^†
• Standardized mortality ratio (SMR)* calculations showed that women and men in the cohort were, respectively, 32 and 25 times more likely to die than women and men in the general population over the study period.
• The crude mortality rate (CMR)** was 3.6/100 person-years over the study period and highest within seven days of EMS attendance (22.2/100 person-years).
• In adjusted analyses, mortality risk was highest within the first seven days post-overdose, especially among individuals with severe overdose symptoms (i.e., Glasgow Coma Scale = 3/15 and/or a respiration rate of ≤6 per minute).

* SMR is calculated by dividing the observed age- and sex-specific mortality rate in the cohort by the expected sex- and age-specific mortality rate in the general population.

** CMR is calculated by dividing total number of deaths during the follow-up period by the total person-years contributed by all participants.

^† Categorized as “accidental poisoning” by the European Shortlist for Causes of Death, 2012 (ICD 10).

Comments: This study shows that the risk of mortality in the week after a non-fatal overdose is very high, particularly among individuals with severe overdose symptoms. The fact that no deaths occurred within two days of EMS attendance indicates that deaths were likely not due to rebound opioid toxicity. Prescription opioid medications and heroin were more common causes of opioid overdose than fentanyl in this cohort; the risk for those with fentanyl use in the US is likely higher. Results indicate an urgent need for targeted interventions for this high-risk group. A non-fatal overdose should be treated like other medical emergencies and patients should have immediate access to evidence-based treatment.

Elliott Brady, MD, MPH^± & Darius A. Rastegar, MD

^± 2024–2025 Rich Saitz Editorial Intern & Addiction Medicine Fellow, Montefiore Einstein Addiction Medicine Fellowship Program

Reference: Eide D, Gjersing L, Danielsen AW, et al. Heightened mortality risk after a non-fatal opioid overdose: risk factors for mortality in the week following emergency treatment. Addiction. 2024;26:1–8.