Abstract BACKGROUND Anemia is a common complication of inflammatory bowel disease (IBD) and can have a significant negative impact on quality of life by causing fatigue and reduced exercise tolerance. However, system wide patterns of anemia recognition and treatment are lacking. The aim of our study is to identify practice patterns of screening for anemia, assessment of iron stores, and administration of iron repletion therapy among a national cohort of patients with IBD. METHODS We conducted a retrospective cohort study of patients with IBD in the national Veterans Affairs (VA) dataset from 2000-2017. IBD patients were identified using a previously validated algorithm using administrative codes for Crohn’s disease (CD) and ulcerative colitis (UC). Laboratory values, patient demographics, and medical treatment data were extracted from the national VA datasets. Anemia was defined as hemoglobin < 13 g/dL in males and < 12g/dL in females. Initial observation of anemia during the study period was considered index anemia date. Analyses were descriptive of proportion of IBD patients with anemia, treatment, or outcomes. Temporal trends were presented as number patients by calendar year. RESULTS Of the 89,687 patients with IBD identified from 2000-2017, 50,781 (56%) were found to have anemia at least once during the study period. The number of IBD patients with anemia increased five-fold during the study period from 3,260 to 15,579 unique patients per calendar year. Testing for iron deficiency among patients with anemia was low- only 36% of anemic patients had iron studies completed within 6 months of anemia result. Of anemic patients who completed iron studies, the vast majority (89%) were consistent with iron deficiency anemia. Of patients with low iron stores, only 23% of patients received iron therapy within 6 months of lab result. Of patients with anemia, only 19% had anemia resolve within 1 year. Hospitalization within 5 years was observed in 30% of patients with anemia, with 60% of hospitalizations occurring within 1 year of index anemia date. IBD-associated surgery within 5 years of index anemia date was observed in only 2% of patients. CONCLUSIONS In a large national cohort of IBD patients, anemia is a common and undertreated complication, and is frequently followed by hospitalization and steroid use. Although iron deficiency is the most common cause of anemia, adequate iron testing and treatment is lacking, which may contribute to the low rates of anemia resolution. Interventions to improve anemia testing and treatment for iron deficiency anemia are needed.