Background: Acetaminophen is one of the most commonly encountered medications in self-poisoning, with a
high rate of morbidity. The prevalence and characteristics of acetaminophen intoxication associated with long
hospital stay in patients are not well defined. Objectives: This study aims to identify the clinical and demographic
factors associated with the length of in-hospital stay (LOS), and to evaluate the effect of early treatment
of acetaminophen overdose patients (8 hours) by intravenous N-acetylcysteine (IV-NAC) on hospital stay.
Methods: This is a retrospective cohort study of hospital admissions for acetaminophen overdose conducted
over a period of 5 years from 1 January 2004 to 31 December 2008. Patients were divided into two groups: LS
group patients had a long hospital stay (> median hours stay in hospital) and SS group patients had a short hospital
stay ( median hours stay in hospital). Variables were abstracted from medical records for comparison
between the two groups. A total of 20 variables were identified for comparison. Parametric and nonparametric
tests were used to test differences between groups depending on the normality of the data. SPSS
15 was used for data analysis. Results: Of the 305 patients, 11 factors were identified in the univariate analysis as
associated with LS. Three independent factors were found to be significant predictors of LS in the multivariate
analysis. The factors associated with LS were seen among patients with a history of abdominal pain after ingestion
of acetaminophen (p ¼ 0.04), who were on IV-NAC administration (p < 0.001) and had an acutely
depressed mood (p ¼ 0.003). Late time to NAC infusion of more than 8 hours was associated with LS rather
than SS (96 patients [57%] and 6 [24%], respectively; p ¼ 0.003). Conclusion: Patients with long hospital stay
have different clinical characteristics compared to patients with short hospital stay. We identified time to
IV-NAC administration is a potentially modifiable factor that may lead to prolonged hospital stay. When risk
assessment indicates that NAC is required, it is highly recommended that NAC be started in the first hours of
admission to reduce the LOS.