Histopathological study of chronic hepatitis B: a comparative study of Ishak and METAVIR scoring systems

ABSTRACT

Ishak and METAVIR scoring systems are among the most commonly used histopathological systems to evaluate chronic hepatitis. To assess the level of agreement between these two scoring systems in patients with chronic hepatitis B. Liver biopsy samples taken from 92 patients with chronic hepatitis B were considered as the training set; 57 more biopsy specimens were used as the validation set. In the training set, grade of necroinflammation and stage of fibrosis for each liver biopsy specimen were determined by two expert liver pathologists using both Ishak and METAVIR systems. Inter-observer variability between the two pathologists was evaluated. Biopsy specimens of the validation set were seen and scored by a third expert pathologist. In the training set, criteria were developed to categorize Ishak grading and staging systems separately to best fit with the METAVIR scoring system. The criteria found in the training set, was then tested in the validation set. The level of agreement between the two scoring systems was assessed by weighted kappa statistics. For the training set, agreement between the two pathologists was excellent. Using our proposed criteria in the training set, there was excellent level of agreement in grading [Kappa = 0.89] and staging [Kappa = 0.99] between Ishak and METAVIR systems. In the validation set, the criteria led to substantial correlation [Kappa = 0.61] in grading, and excellent correlation [Kappa = 0.94] in staging between the two systems. Using our proposed criteria, excellent or at least substantial concordance between Ishak and METAVIR scoring systems can be achieved for the degree of both necro-inflammatory changes and fibrosis