Background and Aims: Anemia is a common complication of inflammatory bowel diseases (IBD), as well as a predictor of poor outcomes. The aim of this study was to determine the prevalence of anemia over time and the management of moderate to severe anemia at a tertiary referral IBD center.

Methods: We retrospectively reviewed the occurrence of anemia at the time of referral or diagnosis and during follow-up at the McGill University Health Centre IBD center. Consecutive patients presenting with an outpatient visit between July and December 2016 and between December 2018 and March 2019 were included. Disease characteristics, biochemistry and medical management, including the need for intravenous iron therapy were recorded.

Results: 1,356 Crohn’s disease (CD) and 1,293 ulcerative colitis (UC) patients [disease duration: 12 (IQR: 6-22) and 10 (IQR: 5-19) years respectively] were included. The prevalence of moderate to severe anemia at referral/diagnosis (15.4% and 8.5%) and during follow-up (11.1% and 8.1%) were higher in CD than in UC patients. In CD, previous resective surgery, perianal disease and elevated C-reactive protein (CRP) at assessment, while in UC steroid therapy, an elevated CRP and fecal calprotectin at assessment were associated with anemia in a multivariate analysis. Anemia improved by >2g/dL in 56.5% after 4-6 weeks (intravenous iron dose >1000 mg in 87% of patients).

Conclusion: Anemia occurred frequently in this IBD cohort, at referral to the center and during follow-up, and contributes to the burden of IBD in referral populations. Most patients were assessed for anemia regularly and with accurate anemia workup; however, the targeted management of moderate to severe anemia was suboptimal.


anemia, ulcerative colitis, iron, Crohn’s disease, inflammatory bowel diseases