Background: Iron deficiency with or without anaemia is common in patients treated in Gastroenterology, especially in inflammatory bowel disease (IBD). IBD patients with iron deficiency usually need high doses of iron, and intravenous iron is an established therapy for these patients. The aim of this study was to investigate treatment routine, effectiveness and safety of iron isomaltoside in clinical practice. The primary endpoint was to determine the probability of relapse of iron deficiency over time defined as re-treatment related to the dose given.
Methods: Participants were recruited from ten hospitals in Denmark, Norway and Sweden as part of a prospective, observational, multicenter study conducted from August 2013 to November 2015. Patients were treated with iron isomaltoside according to the product label and clinical routine.
Results: Of patients included, 82/282 (29%) had Crohn's disease (CD) and 67/282 (24%) had ulcerative colitis (UC). The reference group of 133/282 (47%) non-IBD patients had iron deficiency with or without anaemia due to chronic blood loss, systemic inflammation, malabsorption or malignancy. The median age was 46 (17–93) years and 173/282 (61%) were female. Patients treated with a dose of iron isomaltoside above 1000 mg had 65% lower odds (hazard ratio 0.351) of needing re-treatment compared to those given 1000 mg (p<0.05). There was no significant difference between UC and CD patients (odds ratio 1.65; 95% CI 0.81, 3.35). The majority of the patients 170/278 (61%) received only one treatment of iron isomaltoside during the study, median observation time 19 (1–27) months. In addition to administered dose, baseline haemoglobin (Hb) was an independent predictor of the probability for re-treatment. Administration of iron isomaltoside led to a significant increase in Hb, ferritin and transferrin saturation for both IBD and non-IBD patients (p<0.05). The mean administered dose of iron was 1100 mg, which was lower than the calculated total iron need of 1481 mg for the same patients if calculated from the simplified dosing table as recommended in the ECCO guidelines. After the first treatment 71/191 (37%) of patients were still anaemic. Adverse events were rare, with infusion reactions reported in 6/282 (2%) of patients, one patient being admitted to hospital for treatment. All patients had an uneventful recovery.
Conclusions: Iron isomaltoside was effective with a good safety profile in both IBD and non-IBD patients with iron deficiency. A high dose, especially over 1000 mg, reduced the need for re-treatment. The administration of even higher doses would have been required for full iron correction, indicating that patients receive inadequate iron dosing in routine clinical practice.