Inflammatory bowel disease phenotypes in diverse populations: a global comparative analysis

The aim of this study was to determine if Crohn's disease (CD) and ulcerative colitis (UC) manifest similarly in different parts of the world.

Investigators of cohort studies from around the world were contacted to provide the most recent data from their CD and UC cohorts. Each cohort provided summated and averaged data on pre-specified variables. The Montreal Classification was used for phenotype assessment. Age at diagnosis was stratified into less than 17 years, 17-39 years, and >39 years. Disease location for CD was stratified as ileum only, colon only, ileocolon, upper gastrointestinal and proximal small bowel disease, and perineal penetrating disease. Disease behavior for CD was stratified into inflammatory disease, stricturing disease, and penetrating disease. Location for UC was stratified into proctitis, left-sided colitis, and extensive including subtotal and pancolitis. Reports were classified geographically as Asia, Latin America, South Africa, and "Western" (ie, North America, Europe, and Oceania). These categories were collapsed to "Western" and "non-Western" for analyses.

Data from 54 868 patients with IBD were included. For CD, data were available from nine Western cohorts, 12 Asian cohorts, three Latin American cohorts, and one African cohort. For UC, eight Western cohorts were compared with 11 Asian cohorts, three Latin cohorts, and one African cohort. The demographic and phenotypic distribution for CD and UC in comparisons between Western and non-Western countries were no different. Western cohorts had longer disease durations than non-Western cohorts.

No significant differences were seen in any phenotypic data between the cohorts, suggesting that IBD is similar worldwide.