Iron deficiency anemia impacts disease progression and healthcare resource consumption in patients with inflammatory bowel disease: a real-world evidence study

BACKGROUND: Iron deficiency anemia (IDA) is a common extraintestinal manifestation of inflammatory bowel disease (IBD), affecting around one-third of patients. OBJECTIVE: To compare IBD progression and healthcare resource utilization in patients with and without a co-diagnosis of IDA in a real-world setting. DESIGN: A retrospective comparative study was conducted using Italian entities’ administrative databases, covering 9.3 million health-assisted individuals. METHODS: Adult IBD patients diagnosed with ulcerative colitis and/or Crohn’s disease were enrolled between January 2010 and September 2017. Within 12 months from IBD diagnosis, IDA was identified by at least one prescription for iron and/or IDA hospitalization and/or blood transfusion (proxy of diagnosis). IBD population was divided according to the presence/absence of IDA. Given the nonrandom patients’ allocation, propensity score matching (PSM) was applied to abate potential unbalances between the groups. Before and after PSM, IBD progression (in terms of IBD-related hospitalizations and surgeries), and healthcare resource costs were assessed. RESULTS: Overall, 13,475 IBD patients were included, with an average age at diagnosis of 49.9 years, and a 53.9% percentage of male gender. Before PSM, 1753 (13%) patients were IBD–IDA, and 11,722 (87%) were IBD–non-IDA. Post-PSM, 1753 IBD–IDA patients were matched with 3506 IBD–non-IDA. Before PSM, IBD progression was significantly higher in IBD–IDA (12.8%) than in IBD–non-IDA (6.5%) (p < 0.001). After PSM, IBD progression and IBD-related hospitalizations were significantly (p < 0.001) more frequent in IBD–IDA patients (12.8% and 12.0%, respectively) compared to IBD–non-IDA (8.7% and 7.7%). Consistently, healthcare expenditures resulted significantly higher among IDA patients (p < 0.001), with an overall mean annual cost of €5317 compared to €2798 for patients without IDA. These results were confirmed after PSM matching, as the mean annual total cost/patient in IBD–IDA versus IBD–non-IDA were €3693 and €3046, respectively (p < 0.001). CONCLUSION: In a real-life setting, IDA co-diagnosis in IBD patients was associated with disease progression and higher related economic burden.