Clinical and economic characteristics of emergency department visits due to acetaminophen toxicity in the USA

Objectives: To estimate the number of acetaminophen (APAP) toxicity-related emergency department (ED) visits, and to assess their associated clinical and economic burden in the USA from 2006 to 2010. Design: Cross-sectional, retrospective, large-scale database study. Setting: Non-federal, non-rehabilitation, community EDs in the USA. Participants: Inclusion criteria included any listed diagnosis identifying poisoning by aromatic analgesics paracetamol/APAP or associated supplementary code. Generalised linear models were used to investigate the association between outcomes of inpatient admission, mortality, requirement of invasive mechanical ventilation, charges and inpatient lengths of stay based on patient, hospital and clinical characteristics. Results: Across the 625.2 million ED visits in the USA from 2006 to 2010, 411 811 APAP-related toxicity ED visits were observed, with 45.5% resulting in inpatient admission, 4.7% requiring invasive mechanical ventilation and 0.6% involving death. Overall, the incidence proportion was 27.10 per 100 000 US population, exceeding 70 per 100 000 at age 2 years and ages 16-18 years. The total national bill was $1.06 billion per year (US$2014), and predominantly involved females (65.5%) and intentional self-harm (58.4%), which were notably higher within the 12-20 years age category (female(12-20 years)=74.8%, intentional self-harm(12-20 years)=71.4%). Behavioural and mental health comorbidities were relatively common and associated with an increased relative risk of admission and likelihood of charges almost entirely across all age categories of >= 12 years within the multivariable analyses. The number of ED visits did not appreciably change over time, decreasing by <2% from 2006 to 2010 (n=1351). Multivariable results also suggested no consistent change in outcomes across the study's time horizon. Conclusions: A substantial public health impact of APAP toxicity-related cases was observed in the US from 2006 to 2010, with incidence proportions peaking at age 2 years and ages 16-18 years. After controlling for numerous factors, no consistent change was observed over the 5-year time horizon concerning outcomes of admission, mortality, invasive mechanical ventilation, charges or length of stay.