Prediction of hepatic encephalopathy development in patients with severe acute hepatitis.

To identify factors predicting the development of hepatic encephalopathy, 164 patients with severe acute hepatitis (SAH), defined as acute hepatitis having a prolonged prothrombin time (PT) of < 40% activity but without hepatic encephalopathy, were prospectively observed at 57 major liver centers in Japan. From the data of 65 patients enrolled from 1997 to 1998, a prediction equation was developed by multiple logistic regression analysis and prospectively evaluated using the data of 99 patients since 1999. Of the 164 patients with SAH, 51 (31%) developed hepatic encephalopathy. From the etiologic viewpoint, the percentages of patients developing encephalopathy were highest in non-A-E hepatitis (41.9%). A predictive model, logit(p) = 0.084 x age (year)+ 0.129 x serum total bilirubin (TB, in mg/dL)-0.158 x prothrombin time (%)-2.434, was developed. In conclusion, old age, prolonged PT, elevation of TB, and non-A-E hepatitis are potential risk factors for developing encephalopathy in SAH.