Jürgen Stein, Jennifer Scarlet Haas, Siew Hwa Ong, Kathrin Borchert, Thomas Hardt, Elmira Lechat, Kerry Nip, Douglas Foerster, Sebastian Braun, Daniel C Baumgart

Iron-deficiency anemia and iron deficiency are common comorbidities associated with inflammatory bowel disease (IBD) resulting in impaired quality of life and high health care costs. Intravenous iron has shown clinical benefit compared to oral iron therapy. This study aimed to compare health care outcomes and costs after oral vs intravenous iron treatment for IBD patients with iron deficiency or iron deficiency anemia (ID/A) in Germany. IBD patients with ID/A were identified by ICD-10-GM codes and newly commenced iron treatment via ATC codes in 2013 within the InGef (formerly Health Risk Institute) research claims database. Propensity score matching was performed to balance both treatment groups. Non-observable covariates were adjusted by applying the difference-in-differences (DID) approach. In 2013, 589 IBD patients with ID/A began oral and 442 intravenous iron treatment. After matching, 380 patients in each treatment group were analyzed. The intravenous group had fewer all-cause hospitalizations (37% vs 48%) and ID/A-related hospitalizations (5% vs 14%) than the oral iron group. The 1-year preobservation period comparison revealed significant health care cost differences between both groups. After adjusting for cost differences by DID method, total health care cost savings in the intravenous iron group were calculated to be €367. While higher expenditure for medication (€1,876) was observed in the intravenous iron group, the inpatient setting achieved most cost savings (€1,887). IBD patients receiving intravenous iron were less frequently hospitalized and incurred lower total health care costs compared to patients receiving oral iron. Higher expenditures for pharmaceuticals were compensated by cost savings in other domains.