Fulminant hepatic failure secondary to acetaminophen poisoning: A systematic review and meta-analysis of prognostic criteria determining the need for liver transplantation

Objectives: To summarize and compare different prognostic criteria used to determine need for liver transplantation in patients with fulminant hepatic failure secondary to acetaminophen poisoning. Data Sources: Studies published in the literature that investigated criteria for hepatic transplantation secondary to acetaminophen-induced liver failure as identified by a preestablished MEDLINE strategy (1966 through October 2001). Study Selection: Studies were included if 2 × 2 tables could be reconstructed and if they did not assume that patients undergoing transplantation would have eventually died had they not received the transplant. Data Extraction: Relevant articles were reviewed by two authors independently. Discrepancies or disagreements, if any, on the inclusion or exclusion of studies were resolved by consulting the third author. Data Synthesis: King's criteria (pH < 7.30 or prothrombin time of >100 secs plus creatinine of >300 μmol/L plus encephalopathy grade of ≥3) were evaluated in nine studies, pH < 7.30 in four, prothrombin time of >100 secs in three, prothrombin time of >100 secs plus creatinine of >300 μmol/L plus encephalopathy grade of ≥3 in three, creatinine of >300 μmol/L in two, and one each for increase in prothrombin time day 4, factor V of <10%, Acute Physiology and Chronic Health Evaluation (APACHE) II score of >15, and Gc-globulin of <100 mg/L. King's criteria were more sensitive than pH: 69% (95% confidence interval, 63-75) vs. 57% (95% confidence interval, 44-68). Their specificities were, however, comparable: 92% (95% confidence interval, 81-97) vs. 89% (95% confidence interval, 62-97). APACHE II score of >15 had the highest positive likelihood ratio (16.4) and the lowest negative likelihood ratio (0.19) but was evaluated in only one study. The accuracy measures of all other criteria were lower than that of King's criteria or pH < 7.30. Conclusions: Presently, available criteria are not very sensitive and may miss patients requiring transplantation. Future studies should further evaluate the efficacy of the APACHE II criteria.