Outpatient treatment of acute poisonings in Oslo: poisoning pattern, factors associated with hospitalization, and mortality

BACKGROUND: Most patients with acute poisoning are treated as outpatients worldwide. In Oslo, these patients are treated in a physician-led outpatient clinic with limited diagnostic and treatment resources, which reduces both the costs and emergency department overcrowding. We describe the poisoning patterns, treatment, mortality, factors associated with hospitalization and follow-up at this Emergency Medical Agency (EMA, "Oslo Legevakt"), and we evaluate the safety of this current practice. METHODS: All acute poisonings in adults (> or = 16 years) treated at the EMA during one year (April 2008 to April 2009) were included consecutively in an observational study design. The treating physicians completed a standardized form comprising information needed to address the study's aims. Multivariate logistic regression analysis was used to identify the factors associated with hospitalization. RESULTS: There were 2348 contacts for 1856 individuals; 1157 (62%) were male, and the median age was 34 years. The most frequent main toxic agents were ethanol (43%), opioids (22%) and CO or fire smoke (10%). The physicians classified 73% as accidental overdoses with substances of abuse taken for recreational purposes, 15% as other accidents (self-inflicted or other) and 11% as suicide attempts. Most (91%) patients were treated with observation only. The median observation time until discharge was 3.8 hours. No patient developed sequelae or died at the EMA. Seventeen per cent were hospitalized. Gamma-hydroxybutyric acid, respiratory depression, paracetamol, reduced consciousness and suicidal intention were factors associated with hospitalization. Forty-eight per cent were discharged without referral to follow-up. The one-month mortality was 0.6%. Of the nine deaths, five were by new accidental overdose with substances of abuse. CONCLUSIONS: More than twice as many patients were treated at the EMA compared with all hospitals in Oslo. Despite more than a doubling of the annual number of poisoned patients treated at the EMA since 2003, there was no mortality or sequelae, indicating that the current practice is safe. Thus, most low- to intermediate-acuity poisonings can be treated safely without the need to access hospital resources. Although the short-term mortality was low, more follow-up of patients with substance abuse should be encouraged.