Prevalence, Pathogenesis and Management of Anemia in Inflammatory Bowel Disease: An IG-IBD Multicenter, Prospective, and Observational Study

Background: Anemia is a common extraintestinal manifestation of inflammatory bowel disease (IBD), with a 6% to 74% prevalence and a negative impact on patient survival and quality of life, although the prevalence is apparently declining due to improved disease treatment. We aimed to investigate the prevalence, pathogenesis, and clinical correlates of anemia in Italian patients with IBD. Methods: A multicenter, prospective, observational study, involving 28 Italian gastroenterology centers, was conducted to investigate the epidemiology and consequences of IBD-associated anemia. Clinical and laboratory data of anemic patients were obtained at study enrolment. Results: Anemia was diagnosed in 737 of 5416 adult IBD outpatients (prevalence 13.6%); females were more commonly affected than males (odds ratio, 1.5; 95% confidence interval [CI], 1.2-1.7) and had more severe anemia. In the majority of cases, anemia was due to iron deficiency (62.5% of cases; 95% CI, 58.3%-66.6%), either isolated or in association with inflammation and/or vitamin deficiencies; anemia of inflammation accounted for only 8.3% of cases. More severe anemia was associated with increasing fatigue and worse quality of life. Only 68.9% of anemic patients with iron deficiency (95% CI, 63.4%-73.8%) and 34.6% of those with vitamin deficiencies (95% CI, 26.2%-44.2%) were properly treated with supplementation therapy. Conclusions: In Italy, the prevalence of IBD-associated anemia is lower than previously reported. Anemia of IBD is most commonly due to iron deficiency and contributes to fatigue and poor quality of life, but remains untreated in a large proportion of patients with iron and/or vitamin deficiencies. This study is registered at clinicaltrials.gov as NCT02872376.