Prevalence and trend of anemia in children with inflammatory bowel disease: A national register-based cohort study.

Objective: We determined the prevalence of anemia and its characteristics in children with newly diagnosed inflammatory bowel disease (IBD) and investigated its trend during follow-up.

Methods: An observational, multicenter cohort study of IBD children with anemia at the diagnosis enrolled in the Italian Society of Pediatric Gastroenterology, Hepatology, and Nutrition IBD registry. Data were collected at the diagnosis and at 1 year.

Results: Five hundred eighty-nine (295 Crohn's disease [CD] [50%] and 294 ulcerative colitis [UC]/IBD unclassified [IBDU] [50%]) of 1634 patients with IBD presented with anemia (36%). Anemia rate was higher in CD than in UC (39% vs. 33%, p = 0.009), and most patients had moderate anemia (55%). Children with CD had higher rates of mild anemia than UC (38% vs. 33%, p < 0.0001), while severe anemia was more common in UC (13% vs. 6%, p = 0.001). In CD, lower age at the diagnosis and lower albumin level correlated with anemia severity (p = 0.0007 and <0.0001, respectively). In UC, severe disease was more common in patients with severe anemia compared to those with mild and moderate anemia (20.6% vs. 43.6%, p = 0.01; 17% vs. 43.6%, p = 0.001). At 1 year, 99 children (22.9%) were persistently anemic and were characterized by a more severe disease compared to those who had resolved their anemia.

Conclusions: More than one third of IBD children present with anemia, most commonly moderate. Severe anemia is more common in UC compared to CD. One in four patients is still anemic after 1 year from the diagnosis, suggesting inadequate attention to the issue and the need for dedicated therapeutic management and careful monitoring.