Background: Immigrants moving from low to high prevalence areas of inflammatory bowel disease (IBD) increase disease incidence. Data regarding the IBD phenotype compared to local patients of high prevalence are scarce. Background differences in those factors implicated in IBD pathogenesis (genome, microbiome, immunome and exposome) may result in different clinical features. The aims of the present study were to evaluate IBD phenotypic features as well as therapeutic requirements in de novo IBD immigrant population patients with respect to a local control group.
Methods: We identified de novo IBD immigrant patients from Africa and Latin-America (minimum of 12 months of residence in Spain and with at least 6 months of follow-up) from the respective local database of three tertiary referral centres of IBD. Each immigrant case was matched by gender, type of IBD and year and age at IBD diagnosis (±5 years) with a native Spanish IBD patient (controls). Data regarding type of IBD, location/extent, behaviour and therapeutics and surgery requirements, as well as demographic and epidemiological variables were recorded.
Results: We included 88 cases and 88 controls. Median time from immigration to IBD diagnosis in cases was 103 months (IQR 72–154) with median age at IBD diagnosis of 31 years (IQR 25–37). Among African patients (N=28) with ulcerative colitis, 9% of cases developed steroid-dependence (51% controls, p=0.013), whilst none required biological therapy (for 23% among controls, p=0.025); regarding Crohn's Disease (CD), up to 50% of Africans required surgery for 17% of controls (p=0.041). Among Latin-American patients (N=60) with CD, up to 23% of cases developed steroid-refractoriness (for none of the controls, p=0.034). No other significant differences regarding disease phenotype and demographic and epidemiological features were found neither in UC nor CD between cases and controls.
Conclusions: Although de novo IBD cases in our country seem to have a similar phenotype as in native IBD controls, African patients who develop UC have lower rates of steroid-dependence and biologic therapy requirements. Moreover, CD African patients presented a higher need of surgical treatment than local CD patients. Conversely, no significant differences between Latin-American patients and native Spanish patients were identified except for a higher rate of steroid-refractoriness in CD with respect to local CD patients.