Treatment of opioid overdose in a physician-based prehospital EMS: frequency and long-term prognosis

Background: Prehospital treatment of opioid overdose accounts for a significant proportion of the workload of the emergency system in most major cities. Treatment consists of basic life support and administering naloxone. In our physician-manned mobile emergency care unit (MECU), most patients are released and not admitted to hospital. In this study, we aimed to assess the pattern in the number of episodes with opioid overdose treated by MECU in Copenhagen during a 10-year period and to investigate risk factors for mortality of these patients beyond the initial contact.

Methods: Data were collected prospectively in the MECU database covering all cases of opioid overdose in a 10-year period between 1994 and 2003. The pattern in the number of opioid overdose was analysed in Poisson regression models, and mortality was analysed in Kaplan-Meier plots and in Cox regression models.

Results: A total of 4762 episodes of opioid overdose were recorded. Patients were identified in 3245 of these episodes. The annual number of episodes decreased significantly over the data-collection period: from 639 overdoses out of 4520 (14.1%) patients treated in 1994 to 311 out of 7263 patients treated (4.3%) in 2003. A total of 352 patients had cardiac arrest at the scene. The MECU released 2246 patients (69.3%) after treatment, while 675 (20.8%) were admitted to hospital and 322 (9.9%) died. Long-term prognosis was poor with 14% mortality at 1 year. Long-term mortality was significantly related to increasing age, time of the year and if the patient had previous episodes of opioid overdose.

Conclusions: There has been a significant decrease in the number of opioid overdoses during this 10-year-period. Long-term mortality is high in these patients and highest in those with advanced age and numerous episodes of opioid overdose.