What are the factors associated with the length of hospital stay after acetaminophen overdose?

I read with interest the study performed by Zyoud and colleagues recently published in your journal. They, in a retrospective cohort study, divided the patients who had been admitted to their hospital for acetaminophen overdose into two groups of short and long hospital stay (less and more than a median hospital stay of 36 h, respectively). They compared a total of 20 variables between these two groups and, using multivariate logistic regression analysis, confirmed that 3 variables were statistically different between these 2 groups. The factors associated with long hospital stay were seen among patients who had abdominal pain at presentation, those who had acute depressed mood, and those who were on intravenous N-acetylcysteine (IV-NAC) administration. In this study, the hospital duration ranged from 4 h to 12.5 days (mean: 46 h). The most important concern regarding this study is that, in general, what have been the reasons of admission in those who had been managed without IV-NAC therapy? In their study, a large number of acute overdose patients (approximately 52.1%) were admitted for the treatment despite serum acetaminophen levels below the ‘possible toxicity’ treatment line on the Rumack–Matthew nomogram. Also, in the group of the patients who have been managed by IVNAC, what have been the reasons for continuing hospital stay after the completion of the course of therapy? What were the proper end points for IVNAC therapy? Did standardized guidelines for the treatment of acetaminophen overdose exist during the course of study? Were there any cases, in whom, IV-NAC was continued longer than the authors’ protocol of 20 hours? Were treatment decisions at the discretion of the admitting physicians? In this study, length of hospital stay was calculated as the hour of discharge minus the hour of admission. It can be suggested that some reasons may prolong this length including timing of ingestion (acute, chronic or repeated overdose), complicated acetaminophen overdose, desire for extra caution or a lack of familiarity with treatment guidelines by clinicians, the time needed for psychiatric evaluation (if necessary) and prolonged average time between acetaminophen level and biochemistry (including serum liver enzyme activity, prothrombin time, and creatinine) test orders and their time of receipt at the time of treatment and also before hospital discharge. These are some points that the authors have not noticed and mentioned in their study and can affect the length of hospital stay. Therefore, it would be better if the authors mentioned these factors before considering the clinical and demographic factors in these patients as well as the effect of early treatment of acetaminophen overdose. It seems that even without the statistical analysis, it is quite evident that the patients who present with signs and symptoms of acetaminophen overdose have ingested a large amount of acetaminophen, have an acetaminophen level above the possible toxicity treatment line according to the standard Rumack–Matthew nomogram, and are treated with IV-NAC will have a longer course of hospital stay in comparison to the others. Thank you for this interesting study.