Anemia at the time of diagnosis of inflammatory bowel disease: Prevalence and associated factors in adolescent and adult patients.

BACKGROUND The prevalence, characteristic and determinants of anemia, at the time of inflammatory bowel disease (IBD) diagnosis have yet to be fully elucidated. METHODS Retrospective cross-sectional study. Analytical data and disease characteristics obtained upon diagnosis of 1278 IBD patients [Crohn's disease/ulcerative colitis (CD/UC): 718/560] were collected. RESULTS Anemia was present in 41.2% of patients at diagnosis (47% and 33.8% of CD and UC patients, respectively; p<0.001), being severe in 5.5%. Iron deficiency anemia represented 69.6% of cases, with no differences between CD and UC. Female sex was the strongest risk factor for anemia in both CD and UC (OR 7.11; 95%CI 4.18-12.10 and 6.55; 95%CI 3.39-12.63, respectively), followed by elevated (≥2mg/dL) C-reactive protein (OR 4.08; 95%CI 2.39-6.97 and 4.58; 95%CI 2.26-9.27, respectively). Current smoking was a risk factor for anemia in CD (OR 2.23; 95%CI 1.24-4.02), but a protective one in UC (OR 0.36; 95%CI 0.14-0.92). A penetrating CD behavior increased the risk of anemia (OR 3.34; 95%CI 1.36-8.21); in UC, anemia increased with disease extension (E2+E3) (OR 1.80; 95%CI 1.13-2.86). CONCLUSIONS Female sex and disease activity are major determinants of anemia at IBD diagnosis. Anemia is associated with disease behavior in CD and with disease extension in UC.