Iron Deficiency Anemia: An Overlooked Complication of Crohn's Disease.

Background: There are few studies to evaluate the association between iron deficiency anemia (IDA) and Crohn's disease (CD). We examined this association in a USA-based cohort of patients with CD. Methods: We queried the Nationwide Readmission Databases 2018 using the International Classification of Disease, 10th Revision, and Clinical Modification (ICD-10-CM) codes to identify all adult patients admitted with a diagnosis of CD. Primary outcomes were the prevalence of IDA among patients with CD. Secondary outcomes included inpatient mortality, the length of stay, all-cause 30-day non-elective readmission rate, and total cost of hospitalization. Multivariate regression analysis was performed to study the impact of IDA on inpatient mortality and non-elective readmissions. Results: Of the 72,076 patients discharged from an index hospitalization for CD, 8.1% had IDA. CD patients with IDA had increased length of stays in days (4, interquartile range (IQR): 2 - 6 vs. 3, IQR: 2 - 5; P < 0.001), increased median total charges ($35,160, IQR: $19,786 - $64,126 vs. $31,299, IQR: $17,226 - $59,561; P < 0.001), and were more common to require blood transfusion during hospitalization (13.6% vs. 3.4%, P < 0.001) compared to CD patients without IDA, respectively. IDA was independently associated with increased odds of all-cause 30-day non-elective readmission (odds ratio (OR): 1.254, 95% confidence interval (CI): 1.154 - 1.363, P < 0.001) and increased odds of all-cause 90-day non-elective readmission (OR: 1.396, 95% CI: 1.302 - 1.498, P < 0.001). Conclusions: In a large nationwide cohort of patients hospitalized for CD, we observed a significant burden of IDA. Additionally, we found a significant association between IDA and worse hospitalization outcomes.