Prediction of hepatic encephalopathy in paracetamol overdose: A prospective and validated study

Background: Paracetamol overdose may cause hepatic encephalopathy (HE). Thi s condition demands specialized care and, in some instances, liver transpla ntation evaluation. No model is available for predicting HE. We aimed to se t up and validate a model for predicting the occurrence of HE in paracetamo l overdose, Methods: Prospectively, 161 patients with single-dose paracetam ol overdose and no HE (defined as hepatic coma grade II or more) on admissi on were studied during a 26-month period. Patients admitted during the firs t 13-month period constituted a learning set to construct a model to predic t the occurrence of HE. Patients admitted in the second 13-month period con stituted the validation set. Serial biochemical variables (measured twice d aily), the time line after the overdose, and demographic data were used for univariate testing, and significant factors were assessed in various multi ple logistic regression analyses. Results: Thirty-two patients (20%), 15 in the first period and 17 in the second, developed HE grade II. The best mod el (the highest chi-square) for HE included: log(10) (hours from overdose t o antidote treatment), log(10) (plasma coagulation factors on admission), a nd platelet count hours from overdose (chi-square = 41.2, P < 0.00001). In the validation set 88% (confidence interval (CI), 64%-99%) of the patients who developed HE were correctly predicted by the constructed model, whereas 90% (CI, 79%-96%) of the patients in the non-HE group were correctly predi cted. Conclusions: The constructed model for predicting HE in paracetamol o verdose proved sensitive and accurate in the validation set and should be v aluable for transferring high-risk patients to a liver intensive care unit/ transplantation facility.