Characteristics and outcomes of auto-intoxicated patients admitted to the ICU: A retrospective cohort study

Introduction: Auto-intoxication represents a considerable number of Intensive care unit (ICU) admissions. Literature focusing on characteristics and outcomes of ICU-admitted auto-intoxicated patients is limited.Objectives: We aimed to identify the quantity of intensive care admissions attributable to auto-intoxication in a Belgian tertiary center, to examine characteristics and outcomes of these patients, and to assess the impact of the covid-19 pandemic on these variables.Methods: In this retrospective cohort study, all patients admitted to the ICU of JESSA hospital, Hasselt, Belgium with a diagnosis of auto-intoxication between January 1st 2017 and December 31st 2022, were included in the study. We collected data on patient characteristics, comorbidities, type of intoxication and outcomes including the length of ICU and hospital stay and mortality.Results: In total, 342 patients were included in the dataset, covering 2.44% of all ICU admissions from January 1st 2017 to December 31st 2022. Although auto-intoxication occurred in all age-categories, the age group from 18 to 29 years old, showed the highest prevalence (24%). More woman (57.6%) than man (42.4%) were included in the study. Of all included patients, 21.6% had a history of previous suicide attempt and 36.5% of previous auto-intoxication. The most common substances ingested were sedatives (44.4%), illicit drugs (20.2%), analgesics (17.8%), and antidepressants (16.7%) whereas in 54.1% of the cases, a combination of substances was ingested. Type of intoxication was separated into four groups: suicide attempt, accidental, iatrogenic and recreational use with suicide attempt accounting for 71.3% of all auto-intoxications. The prevalence of ICU-admitted auto-intoxicated patients remained stable over the 5-year study period. An impact of the Covid-19 pandemic on this prevalence could not be established. Overall mortality was low with an ICU- and hospital mortality of 1.75% and 2.6% respectively. Total mortality at time of dataset closure, on the other hand, was 7.2%.Conclusions: The impact of auto-intoxication on ICU resource utilization is relatively high and the risk of recidivism is substantial. ICU- and in-hospital mortality after auto-intoxication is low, although these patients have a substantial risk for death in years to come after hospital discharge.