1447Gastric histopathology by Helicobacter pylori cagA status in Arctic Canada

Abstract

Abstract Background Our community-driven projects address concerns of Canadian Arctic Indigenous communities about Helicobacter pylori (Hp) infection, responsible for elevated gastric cancer mortality in the region. Community research partners wished to learn whether bacterial characteristics determine severity of Hp-related disease in their communities. We aimed to describe gastric histopathology by cagA genotype of Hp isolated from residents of 7 Indigenous communities in the Northwest Territories and Yukon. Methods Participants underwent gastroscopy with 5-6 biopsies taken for histopathological assessment and 2 biopsies taken for tissue culture during 2008-2017. We used multiple PCR reactions and DNA sequence analysis to classify Hp genotypes as cagA+ or cagA-. A single pathologist used the updated Sydney classification system to grade severity of 5 gastric pathology outcomes: Hp density; chronic gastritis; active gastritis; atrophy; and intestinal metaplasia. We estimated prevalence of each outcome with 95% confidence intervals (CI) by gastric subsite and cagA status. Results Of 262 Hp isolates assessed, 142 (54%) were cagA+. Prevalence of moderate-high Hp density, severe chronic gastritis, moderate-severe active gastritis, atrophy, and metaplasia were (%[CI]): respectively, 78[70-85], 44[36-53], 65[56-72], 55[46-63], 25[18-33] in cagA+ participants and 61[52-70], 35[27-44], 31[23-40], 32[23-41], 8[4-15] in cagA- participants. cagA+ participants had higher prevalence of all outcomes in antrum and corpus. Conclusion Hp-infected Indigenous residents of Arctic Canada who harbored cagA-positive strains had higher prevalence of more severe gastric pathology than those with cagA-negative strains. Key messages Community-driven research answers questions posed by those who bear the disease burden.