Inter-observes agreement of Ishak and Metavir scores in histological evaluation of chronic viral hepatitis B and C

Many classification systems are currently used for histological evaluation of the severity of chronic viral hepatitis, including the Ishak and Metavir scores, but there is not a consensus classification. The objective of this work was to study the intra and inter-observers agreement of these two scores in the histopathological analysis of liver biopsies in patients with chronic viral hepatitis B or C. Fifty nine patients were included in the study, 26 had chronic hepatitis C and 33 had chronic hepatitis B. To investigate the inter-observers agreement, the liver biopsies were analyzed separately by two pathologists without prior consensus reading. The two pathologists conducted then a consensual reading before reviewing all cases independently. Cohen's kappa coefficient was calculated and in case of asymmetry Spearman's rho coefficient. Before the consensus reading, the agreement was moderate for the analysis of histological activity with both scores (Metavir: kappa=0.41, Ishak: rho=0.58). For the analysis of fibrosis, the agreement was good with both scores (Metavir: kappa=0.61, Ishak: rho=0.86). The consensus reading has improved the reproducibility of the activity that has become good with both scores (Metavir: kappa=0.77, Ishak: rho=0.76). For fibrosis improvement was observed with the Ishak score which agreement became excellent (kappa=0.81). In conclusion, we recommend in routine practice, a combined score: Metavir for activity and Ishak for fibrosis and to make a double reading for each biopsy.