Laboratory-based scoring system for prediction of hepatic inflammatory activity in patients with autoimmune hepatitis

Summary Background & Aims In autoimmune hepatitis (AIH), inflammation is closely related to fibrosis. Although transaminase levels are commonly used to assess hepatic inflammation, they may not relate directly to the histology. We developed a noninvasive diagnostic score as an alternative to liver biopsy to help optimize treatment for AIH and monitor disease progress. Methods Eighty‐two participants with type 1 AIH who had undergone liver biopsy were included (44 in training and 38 in validation sets). Liver histology was assessed according to the histologic activity index (HAI; score 0–18) and Ishak's histologic fibrosis index (HFI; score 0–6). High inflammation was defined as HAI>4, and advanced fibrosis was defined as HFI>2. Routine laboratory test findings and stepwise linear regression were used to develop the best models predicting HAI and HFI. The best cut‐off value to predict high inflammation and advanced fibrosis for these formulas was then calculated based on receiver‐operating characteristic analysis. Results The cut‐off value for a model predicting high inflammation was ≥3.57 (AUROC = 0.93; 95% CI: 0.86–1.00), with 100% sensitivity and 85% specificity. High inflammation was confirmed with an 81% positive predictive value and excluded with a 100% negative predictive value. In the validation set, the sensitivity, specificity, positive predictive value and negative predictive values were 100, 56, 88 and 100% respectively. The diagnostic yield of the fibrosis score was unsatisfactory. Conclusions The noninvasive inflammatory score based on four routine laboratory parameters discriminated patients with and without significant hepatic inflammation and may facilitate follow‐up of type 1 AIH patients.