A multicentre prospective double blinded randomised controlled trial of intravenous iron (ferric Derisomaltose (FDI)) in Iron deficient but not anaemic patients with chronic kidney disease on functional status

Background: Iron deficiency (ID) is common in patients with chronic kidney disease (CKD). Intravenous (IV) iron in heart failure leads to improvement in exercise capacity and improvement in quality-of-life measurements; however, data in patients with CKD are lacking. Methods: The Iron and the Heart Study was a prospective double blinded randomised study in non-anaemic CKD stages 3b-5 patients with ID which investigated whether 1000 mg of IV iron (ferric derisomaltose (FDI)) could improve exercise capacity in comparison to placebo measured at 1 and 3 months post infusion. Secondary objectives included effects on haematinic profiles and haemoglobin, safety analysis and quality of life questionnaires (QoL). Results: We randomly assigned 54 patients mean (SD) age for FDI (n = 26) 61.6 (10.1) years vs placebo (n = 28; 57.8 (12.9) years) and mean eGFR (33.2 (9.3) vs. 29.1 (9.6) ml/min/1.73m(2)) at baseline, respectively. Adjusting for baseline measurements, six-minute walk test (6MWT) showed no statistically significant difference between arms at 1 month (p = 0.736), or 3 months (p = 0.741). There were non-significant increases in 6MWT from baseline to 1 and 3 months in the FDI arm. Haemoglobin (Hb) at 1 and 3 months remained stable. There were statistically significant increases in ferritin (SF) and transferrin saturation (TSAT) at 1 and 3 months (p < 0.001). There was a modest numerical improvement in QoL parameters. There were no adverse events attributable to IV iron. Conclusion: This study demonstrated a short-term beneficial effect of FDI on exercise capacity, but it was not significant despite improvements in parameters of iron status, maintenance of Hb concentration, and numerical increases in functional capacity and quality of life scores. A larger study will be required to confirm if intravenous iron is beneficial in iron deficient non-anaemic non-dialysis CKD patients without heart failure to improve the 6MWT.