Anaemia in Patients with Inflammatory Bowel Disease - A Nationwide Cross-Sectional Study

Anaemia is the most common complication in patients with inflammatory bowel disease (IBD). This study aims to assess the prevalence of anaemia in IBD patients and to know its characteristics with regard to the main IBD clinical features.

An observational cross-sectional multicentre study was conducted. We included all patients who had an appointment at the 15 participating centres during the period of 1 month, and who met the following selection criteria: age ≥18, diagnosis of IBD. Disease activity was evaluated by Harvey-Bradshaw Index (HBI) for Crohn's disease (CD), and by Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis (UC).

One thousand three hundred and thirteen patients, were included: 54.8% female, mean age 42.8 (interquartile range (25th-75th): 31-53 years), 59% had a diagnosis of CD, 39% of UC and 2% IBD unclassified. The median follow-up since diagnosis was 7 years. The ongoing treatment was aminosalicylates (63.1%), corticosteroids (11.6%), immunomodulators (36.4%) and anti-tumour necrosis factor (27.3%). Anaemia was identified in 244 patients, representing a prevalence of 18.6% (95% CI 16.6-20.9). A majority of cases (90%) have mild/moderate anaemia (mean haemoglobin 11.3 ± 0.8 g/dl). Anaemia was significantly higher in females (p = 0.006), but there were no differences between CDs (19.1%) and UCs (17.7%; p = 0.688). Anaemia was more frequent in patients with active disease (HBI >4; SCCAI >2) than in those in clinical remission (33.6 vs. 15.6%, p < 0.001) and in patients on steroids (36.8%) vs. other treatments (p < 0.001). Only 47% of patients with anaemia were under any specific treatment (oral iron 67%; intravenous iron 41%).

Anaemia was more frequent in patients with active disease and in those on corticosteroids. The treatment of anaemia still seems undervalued, whereas more than half of anaemic patients were not receiving any specific treatment and the use of oral iron prevails contrarily to current recommendations.