Mortality and repeated poisoning after self-discharge during treatment for acute poisoning by substances of abuse: a prospective observational cohort study

Abstract Background Though substance use is a known risk factor for self-discharge, patients self-discharging during treatment for acute poisoning have not previously been described. We charted characteristics of patients self-discharging during treatment for acute poisoning by substances of abuse looking for associations between self-discharge, repeated poisoning, and death. Methods All patients 12 years and older treated for acute poisoning by substances of abuse at an emergency outpatient clinic in Oslo, Norway, were included consecutively from October 2011 through September 2012. We collected data on gender, age, main toxic agent, suicidal intention, homelessness, history of severe mental illness, and self-discharge. Information on deaths was retrieved from the National Cause of Death Register. We did a multiple logistic regression analysis to look for associations between self-discharge and repeated poisoning and a Cox regression analysis for associations between self-discharge and death. Results During one year, 1731 patients were treated for 2343 episodes of acute poisoning by substances of abuse. Two-hundred-and-sixty-six (15%) patients self-discharged during at least one poisoning episode. Self-discharging patients were older, median age 39 years vs 32 years (p