Preoperative anaemia is a risk factor for adverse postoperative outcomes after cardiac surgery. Iron deficiency is a frequent cause of low preoperative haemoglobin. An effective treatment for preoperative anaemia associated with iron deficiency has not been determined.

We conducted a single-centre, open-label, pragmatic randomised trial, enrolling 156 elective cardiac surgery patients who had low preoperative haemoglobin (100–130 g L⁻¹) with iron deficiency (serum ferritin <100 μg L⁻¹ or transferrin saturation <30%) to compare intravenous ferric derisomaltose 1000 mg and darbepoetin 200 μg subcutaneously (intervention group) with oral ferrous sulphate 600 mg daily (control group). The primary outcome was transfusion of at least one unit of allogeneic red cells during surgery and within the following 5 days. Secondary outcomes included the change in haemoglobin concentration between randomisation and surgery, red cell transfusion volume, postoperative blood loss, pre-specified postoperative complications, length of hospital stay, and in-hospital death.

The odds of red cell transfusion were lower in the intervention group compared with the control group (adjusted odds ratio=0.33; 95% confidence interval [CI], 0.15–0.75; P=0.008). Of the secondary outcomes, the only significant difference was the increase in haemoglobin between randomisation and surgery, intervention vs control 9.5 g L⁻¹ (95% CI, 6.8–12.2; P<0.001).

In patients with a low preoperative haemoglobin and iron deficiency, preoperative treatment with a single dose of ferric derisomaltose and darbepoetin decreased the proportion of participants who received a perioperative blood transfusion as a consequence of a greater increase in haemoglobin compared with treatment with oral ferrous sulphate.

ISRCTN Number: 41421863; EUDRACT number: 2011-003695-36.