title: Characteristics of acute and sub-acute liver failure in China: nomination, classification and interval.
abstract: OBJECTIVE
  Unlike most other countries, in China, liver failure is termed as severe hepatitis. However, there are two differences between liver failure and severe hepatitis: the interval of acute and sub-acute severe hepatitis and the etiology. The aims of this study were to assess the best cutoff time-point to distinguish between acute and sub-acute severe hepatitis caused mainly by hepatitis B virus (HBV; 67.5%) in China and to determine whether the Chinese classifications of severe hepatitis can meet the international criteria based on pathological features and clinical characteristics.
  
  
  METHODS
  A total of 157 patients with acute, sub-acute and chronic severe hepatitis were involved in the study. Their clinical findings, laboratory data and liver biopsies were retrospectively analyzed.
  
  
  RESULTS
  The different incidences of complications between acute and sub-acute severe hepatitis were significant if the cutoff point was set at 15 days or 4 weeks (P < 0.01), but there is no significant differences if the cutoff was 8 weeks. Identifying the better cutoff point with a receiver-operator characteristic curve showed that 28 days was better than 15 days (sensitivity 100%vs 92%; specificity 75%vs 53%). The major differences in histopathology between acute and sub-acute severe hepatitis were: (i) there was a single hepatic necrosis in acute severe hepatitis, but repeated and continuous hepatic necrosis in sub-acute severe hepatitis; and (ii) survivors of acute severe hepatitis had full hepatocyte regeneration in the native liver architecture. Regeneration in survivors with sub-acute severe hepatitis indicated the destruction of nodular architecture; new and old necrosis appeared at the same time. When the cutoff point for acute and sub-acute severe hepatitis was set at 15 days, some sub-acute severe hepatitis cases (full hepatocyte regeneration and one massive necrosis) had an overlap in pathological features with acute severe hepatitis. If the cutoff time-point was set at 4 weeks, the clinical features between acute and sub-acute, as well as the pathological changes, were clearly distinguished.
  
  
  CONCLUSIONS
  The best cutoff time-point to distinguish between acute and sub-acute severe hepatitis is 4 weeks. This classification meets the international criteria based on the present clinical and pathological results.
authors.affiliation: Beijing Youan Hospital, Capital University of Medical Sciences, Beijing, China. liuqing7@yahoo.com
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Tailing
authors.initials: T
authors.lastname: Wang
authors.forename: Qingguo
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Shi
authors.forename: Wenbin
authors.initials: W
authors.lastname: Dao
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D003128:Coma / Q000150:complications / Q000453:epidemiology; D005260:Female; D006505:Hepatitis / Q000150:complications / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D017114:Liver Failure, Acute / Q000145:classification* / Q000150:complications / Q000453:epidemiology / Q000209:etiology; D008297:Male; D012372:ROC Curve