2025 Southeastern Residency Conference

Title:
Assessment of an AST:ALT Ratio for Predicting Clinical Recovery After Acetaminophen Poisoning


Authors:
Andrew Norton; Raymond Patterson; Jenna Jewett; Faisal S. Minhaj


Objective:
Evaluate the utility of an AST:ALT ratio for predicting clinical recovery after acetaminophen poisoning.


Self Assessment Question:
Based on the available evidence, should an AST:ALT ratio be used as a surrogate endpoint for determining when to discontinue NAC therapy? 


Background:
Previously, a transaminase ratio of 0.4 or less was proposed as a treatment cutoff for recovery of acetaminophen (APAP) toxicity. This study aims to evaluate the suggested transaminase ratio of <0.4 in a broader population by including all patients with transaminitis thought to be caused by acetaminophen toxicity. We also aim to evaluate different transaminase ratio thresholds to determine if a different ratio is applicable in a patient population that primarily consists of non-severe acetaminophen poisoning.


Methods:
This was a retrospective study conducted by reviewing the electronic medical record of patients who presented to WKRMC between January 1, 2022, and May 1, 2024, and received at least one dose of N-acetylcysteine (NAC) for the treatment of suspected or confirmed APAP toxicity. A total of 84 patients were included in the analysis, with a minimum requirement of 10 patients who received extended NAC therapy (i.e., beyond the standard 72-hour oral course or 21-hour intravenous course). 34 out of 84 patients had at least 1 AST or ALT value of 100 IU/L or more and completed their NAC treatment at WKRMC were included in the primary endpoint. This was determined to be exempt from IRB review at Wellstar Kennestone Regional Medical Center.


Results:
Of the 84 patients that were included in this study, only 34 (41%) patients achieved an AST:ALT ratio of 0.4 or less at the completion of NAC therapy. The most identified co-ingestions included EtOH, NSAIDS, opioids, and benzodiazepines. Extended NAC therapy was utilized in 17 (20%) patients.


Conclusion:
Evaluation of a transaminase treatment ratio of 0.4 or less did not result in a viable endpoint for NAC therapy discontinuation in our patient population for APAP toxicity. Additionally, there was no other ratio threshold endpoint deemed clinically significant for NAC therapy discontinuation.