Background/aims: There are no pathognomonic features of autoimmune hepatitis (AIH). Its diagnosis requires the exclusion of various other conditions. The aim of this study was to validate indirectly the International Autoimmune Hepatitis Group (IAHG) scoring system in diagnosing AIH.
Methods: Twenty-six patients with Type 1 AIH and female patients with chronic hepatitis B (n=34), chronic hepatitis C (n=25), or toxic hepatitis (n=13) were evaluated according to 9 categories of pretreatment minimum required parameters proposed by IAHG. Aggregate scores of AIH to those of non-AIH groups, which were assessed before and after extracting the proportions of etiologic factors, were also compared and evaluated.
Results: While aggregate scores of non-AIH groups, before extracting the proportions of etiologic factors, were 5.2+/-1.8, 5.6+/-1.1, and 7.4+/-1.2 in that order, those of AIH groups were 12.8+/-1.7. These were significantly higher than those of non-AIH groups (p<0.01). All patients in AIH groups and only 1 patient in a non-AIH group showed aggregate scores of more than 10. Aggregate scores after extracting the proportions of etiologic factors were more than 4 in all, except 2, patients. These should have been consistent with 10 if there were no etiologic factors in non-AIH groups.
Conclusion: The IAHG scoring system might have a relatively excessive importance to the scores of categories excluding distinct etiologies from AIH. It might be difficult to differentiate AIH from chronic liver diseases of indistinct cause based on the IAHG scoring system.