Background and aims: Anaemia is an important complication of inflammatory bowel disease (IBD). The aim of this study was to determine the prevalence of anaemia and the practice of anaemia screening during the first year following diagnosis in a European prospective population-based inception cohort.

Methods: Newly diagnosed IBD patients were included and followed prospectively for one year in 29 European and 1 Australian centre. Clinical data including demographics, medical therapy, surgery and blood samples were collected. Anaemia was defined according to the World Health Organization.

Results: A total of 1,871 patients (CD: 686, 88%; UC: 1,021, 87%; IBDU 164. 81%) were included in the study. The prevalence of anaemia was higher in CD than in UC patients and overall, 49% of CD and 39% of UC patients had at least one instance of anaemia during the first 12 months after diagnosis. UC patients with more extensive disease and those from Eastern European countries, and CD patients with penetrating disease or colonic disease location, had higher risks of anaemia. CD and UC patients in need of none or only mild anti-inflammatory treatment had a lower risk of anaemia. In a significant proportion of patients, anaemia was not assessed until several months after diagnosis, and in almost half of all cases of anaemia a thorough work-up was not performed.

Conclusions: Overall, 42% of patients had at least one instance of anaemia during the first year following diagnosis. Most patients were assessed for anaemia regularly; however, a full anaemia work-up was frequently neglected in this community setting.