Anemia in Inflammatory Bowel Disease Outpatients: Prevalence, Risk Factors, and Etiology

Anemia is common in inflammatory bowel disease (IBD). However, epidemiological studies of nonwestern IBD populations are limited and may be confounded by demographic, socioeconomic, and disease-related influences. This study evaluated the prevalence, risk factors, and etiology of anemia in Brazilian outpatients with IBD. Methods. In this cross-sectional study, 100 Crohn's disease (CD) patients and 100 ulcerative colitis (UC) subjects were assessed. Anemia workup included complete blood count, ferritin, transferrin saturation, serum levels of folic acid and vitamin B-12, and C-reactive protein (CRP) concentration. Results. The overall prevalence of anemia in IBD was 21%. There was no significant difference in the prevalence of anemia between CD subjects (24%) and UC (18%). Moderate disease activity (OR: 3.48, 95% CI, 1.95-9.64, P = 0.002) and elevated CRP levels (OR: 1.8, 95% CI, 1.04-3.11, P = 0.02) were independently associated with anemia. The most common etiologies of anemia found in both groups were iron deficiency anemia (IDA; 10% on CD and 6% on UC) followed by the anemia of chronic disease (ACD; 6% for both groups). Conclusions. In Brazilian IBD outpatients, anemia is highly concurrent condition. Disease moderate activity as well as increased CRP was strongly associated with comorbid anemia. IDA and/or ACD were the most common etiologies.