Diagnostic criteria for autoimmune hepatitis (AIH) have been created and revised by the International Autoimmune Hepatitis Group (IAIHG). Simplified criteria have been created, but remain independently unvalidated. We report on the diagnostic accuracy of the simplified criteria in patients across a range of diagnoses, including a subset of patients presenting with fulminant liver failure who required liver transplant. Patients with AIH and non-AIH etiologies of liver disease were identified from dedicated patient databases. Parameters relevant to the simplified and 1999 IAIHG criteria were recorded, and sensitivity, specificity, and positive and negative predictive values for scores of >or=6 (probable AIH) and >or=7 (definite AIH) were calculated. A total of 549 patients with chronic liver disease were evaluated, (221 with AIH, 26 with variant syndromes, and 302 with non-AIH). For scores >or=6, sensitivity was 90%, and specificity was 98% with positive and negative predictive values of 97% and 92%, respectively. For scores >or=7; sensitivity was 70%, and specificity was 100% with positive and negative predictive values of 100% and 74%, respectively. Seven false positive diagnoses of AIH occurred, all with simplified scores of 6. Concordance with 1999 criteria was 90% for probable and 61% for definite AIH. The frequency of an overall diagnosis of AIH (probable or definite AIH) among the 70 patients with fulminant liver failure was 24% for simplified criteria and 40% for 1999 criteria, respectively.
Conclusion: The simplified criteria retain high specificity but exhibit lower sensitivity for scores of >or=7. The explanations for this are unclear but may relate to loss of such discriminating information as response to corticosteroids. Prospective evaluation of these criteria is required to corroborate these observations.