Factors to improve the interobserver agreement for gastric atrophy and intestinal metaplasia: Consensus of definition and criteria

Abstract

Aims

Intestinal metaplasia and atrophy of the gastric mucosa are associated with Helicobacter pylori infection and are considered premalignant lesions. The updated Sydney system is used to these parameters but experienced pathologists and consensus processes are required for interobserver agreement. We sought to determine the influence of consensus process on assessment of intestinal metaplasia and atrophy.

Methods and results

Two study sets were used; consensus set and validation set. The consensus set was circulated and 5 gastrointestinal pathologists independently evaluated them using the updated Sydney system. After then the consensus of the definitions was determined in the first consensus meeting. The same set was recirculated to determine the effect of the consensus. The second consensus meeting was held to standardize the grading criteria and the validation set was circulated to determine the influence. Two additional circulations were performed to assess the maintainance of consensus and intraobserver variability. Interobserver agreement of intestinal metaplasia and atrophy was improved through consensus process (intestinal metaplasia: baseline κ=0.52 vs. final κ=0.68, p=0.006; atrophy: baseline κ=0.19 vs. final κ=0.43, p<0.001). Higher interobserver agreement in atrophy was observed after consensus of definition (pre-consensus: κ=0.19 vs. post-consensus: κ=0.34, p=0.001). There was improved interobserver agreement in intestinal metaplasia after standardization of the grading criteria (pre-standardization: κ=0.56 vs. post-standardization: κ=0.71, p=0.010).

Conclusions

This study suggests that interobserver variability regarding intestinal metaplasia and atrophy may result from lack of a precise definition and fine criteria, and can be reduced by consensus of definition and standardization of grading criteria.

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