Association of intestinal granulomas with smoking, phenotype, and serology in Chinese patients with Crohn's disease

INTRODUCTION: Crohn's disease (CD) is a heterogenous disease characterized by variable manifestations and outcomes, and increasing in incidence in China. Phenotypic classification has been proposed to assist in subtyping of disease. Non-caseating intestinal granulomas are a hallmark of CD, but whether intestinal granulomas help predict Chinese CD phenotypes or determine severity, is not known. AIMS: To determine the association between intestinal granulomas with CD phenotype, severity, risk factors, and serological markers. METHODS: This was a single-centre study of consecutive definite Chinese CD cases. Granulomas were diagnosed by an experienced GI pathologist. Correlation with the Vienna Classification and other parameters was performed. RESULTS: Eighty Chinese CD patients were recruited, 40 (50%) of whom had intestinal granulomas. Intestinal granulomas were independently associated with the stricturing behavior (OR: 4.71; 95% CI: 1.41-15.72), colonic location of disease (OR: 26.96; 95% CI: 2.68-271.14), but not with age of CD diagnosis. Current or previous smoking protected against the development of granulomas (OR: 0.16; 95% CI: 0.04-0.59). Granulomas were not associated with peri-anal involvement, extra-intestinal manifestations, anti-neutrophil cytoplasmic antibody or anti-Saccharomyces cerevisiae antibody serology, or severity of CD gauged by the requirement of major intestinal surgery or immunomodulating therapy. CONCLUSIONS: Intestinal granulomas in the setting of CD may be helpful in determining phenotypic subtypes of CD, but is unhelpful in predicting disease severity. Smoking impairs the formation of granulomas in CD.