Five-year mortality after acute poisoning treated in ambulances, an Emergency outpatient clinic and hospitals in Oslo

Background: The long-term mortality after prehospital treatment for acute poisoning has not been studied previously. Thus, we aimed to estimate the five-year mortality and examine the causes of death and predictors of death for all acutely poisoned patients treated in ambulances, the emergency outpatient clinic, and hospitals in Oslo during 2003-2004. Methods: A prospective cohort study included all adults (>= 16 years; n=2045, median age=35 years, male=58%) who were discharged after treatment for acute poisoning in ambulances, the emergency outpatient clinic, and the four hospitals in Oslo during one year. The patients were observed until the end of 2008. Standardized mortality rates (SMRs) were calculated and multivariate Cox regression analysis was applied. Results: The study comprised 2045 patients; 686 treated in ambulances, 646 treated in the outpatient clinic, and 713 treated in hospitals. After five years, 285 (14%) patients had died (four within one week). The SMRs after ambulance, outpatient, and hospital treatment were 12 (CI 9-14), 10 (CI 8-12), and 6 (CI 5-7), respectively. The overall SMR was 9 (CI 8-10), while the SMR after opioid poisoning was 27 (CI 21-32). The most frequent cause of death was accidents (38%). In the regression analysis, opioids as the main toxic agents (HR 2.3, CI 1.6-3.0), older age (HR 1.6, CI 1.5-1.7), and male sex (HR 1.4, CI 1.1-1.9) predicted death, whereas the treatment level did not predict death. Conclusions: The patients had high mortality compared with the general population. Those treated in hospital had the lowest mortality. Opioids were the major predictor of death.