The NIMO Scandinavian Study: A Prospective Observational Study of Iron Isomaltoside Treatment in Patients with Iron Deficiency

Abstract

Background: Intravenous iron allows for efficient and well-tolerated treatment in iron deficiency and is routinely used in diseases of the gastrointestinal tract.

Objective: The aims of this study were to determine the probability of relapse of iron deficiency over time and to investigate treatment routine, effectiveness, and safety of iron isomaltoside.

Methods: A total of 282 patients treated with iron isomaltoside were observed for two treatments or a minimum of one year.

Results: Out of 282 patients, 82 had Crohn's disease and 67 had ulcerative colitis. Another 133 patients had chronic blood loss, malabsorption, or malignancy. Patients who received an iron isomaltoside dose above 1000 mg had a 65% lower probability of needing retreatment compared with those given 1000 mg. A clinically significant treatment response was shown, but in 71/191 (37%) of patients, anaemia was not corrected. The mean dose given was 1100 mg, lower than the calculated total iron need of 1481 mg. Adverse drug reactions were reported in 4% of patients.

Conclusion: Iron isomaltoside is effective with a good safety profile, and high doses reduce the need for retreatment over time. Several patients were anaemic after treatment, indicating that doses were inadequate for full iron correction. This trial is registered with NCT01900197.

Figure 1

Patient flow diagram (based on CONSORT 2010). CD: Crohn's disease; IBD: inflammatory bowel disease; UC: ulcerative colitis.

Figure 2

Probability of retreatment related to iron isomaltoside dose. The survival plot was obtained by using the Cox proportional hazards model with dose and diagnosis as factors and baseline haemoglobin as covariate. The probability (percent) of retreatment with iron isomaltoside at 52 weeks after the first treatment for each dose group was calculated from the survival curve. The number of patients at weeks 0, 52, and 100 for each dose group includes all patients.

Figure 3

Change in haemoglobin (Hb) after the first iron isomaltoside treatment in anaemic patients with available pre- and posttreatment Hb measures. The time of evaluation corresponded to the time between the last administration of first iron isomaltoside treatment and blood test follow-up and occurred during a mean (SD) time of 7.1 (6.0) weeks for anaemic patients at baseline and during a mean (SD) time of 6.1 (4.7) weeks for patients with Hb < 10 g/dL at baseline. The p value calculations were obtained by analysis of covariance test with diagnosis and dose as factors and pretreatment laboratory parameter concentration as covariate.