Interobserver variation in histopathological assessment of Helicobacter pylori gastritis

Because the presence or absence of H pylori infection has important implications for therapeutic decisions based on histological assessment, the reproducibility of Sydney system is important. The study was designed to test the reproducibility of features of Helicobacter pylori gastritis, using the updated Sydney classification.

Gastric biopsies of 40 randomly selected cases of H pylori gastritis were scored semiquantitatively by three pathologists. Variables analysed included chronic inflammation, inflammatory activity, atrophy, intestinal metaplasia, H pylori, surface epithelial damage. Kappa values below 0.5 represented poor, those between 0.5 and 0.75 good and values over 0.75 excellent interobserver agreement.

The best interobserver agreement (kappa=0.62) was present for intestinal metaplasia. The agreement was the poorest for evaluating atrophy (kappa=0.31).

Although the results of this study were in accordance with some previous studies, an excellent agreement could not be reached for any features of H pylori gastritis. This low degree of concordance is assumed to be due to the personal evaluation differences in grading the features, the lack of standardized diagnostic criteria, and the ignorance to reach a consensus about the methods to be used in grading the features of H pylori gastritis before initiating the study.