Validation study of villous atrophy and small intestinal inflammation in Swedish biopsy registers

Background: Small intestinal biopsy with villous atrophy (VA) is the gold standard for the diagnosis of celiac disease (CD). We validated VA (Marsh 3) and small intestinal inflammation without VA (Marsh 1+2) in Swedish regional biopsy registers. Methods: All pathology departments in Sweden (n = 28) were searched to identify individuals with VA or duodenal/jejunal inflammation. The validation consisted of blinded examination of biopsy samples, manual review of biopsy reports, web surveys, and patient chart reviews of 121 individuals with VA and 39 with inflammation. Results: We identified 29,148 individuals with VA and 13,446 individuals with inflammation. In a blinded examination, Swedish pathologists correctly classified 90% of biopsies with VA. Manual screening of 1,534 biopsy reports (performed by co-author JFL and a research assistant) found that comorbidity other than CD was rare. IBD was the most common comorbidity and occurred in 0.3% of biopsies with VA (1.6% in inflammation). Among 114 patients with VA and available data, 108 (95%) had a clinical diagnosis of CD. 79% of the validated individuals with VA and 64% of those with inflammation had documented gastrointestinal symptoms prior to biopsy. 88% of the validated individuals with VA had positive CD serology before their first biopsy. 172/180 (96%) of Swedish gastroenterologists and 68/68 (100%) of pediatricians perform a small intestinal biopsy in at least 9 out of 10 individuals prior to diagnosis of CD. Conclusion: Regional biopsy data are feasible to identify individuals with CD and small-intestinal inflammation. The specificity of CD is high in villous atrophy.