The influence of pre-operative iron-deficiency anaemia on the outcome after major non-cardiothoracic surgery

Background: Pre-existing pre-operative anaemia is associated with an adverse post-operative outcome. The aim of this study was to analyse the influence of a pre-operative anaemia, especially one that is caused by iron-deficiency, on the post-operative outcome after major non-cardiothoracic surgery. Methods: This was a retrospective study with 1,192 patients who had undergone non-cardiothoracic surgery. The patients were divided into three groups according to their pre-operative haemoglobin levels (group I: Hb >12 g/dl (n=795), II: Hb 10-12 g/dl (n=254), III: Hb <10 g/dl (n=143)). MCH and MCV were used as a screening parameter to classify iron deficiency anaemia. The number of transfused RBCs (red blood cell concentrates), the length of stay as well as postoperative adverse events and in-hospital mortality were evaluated. Results: More RBCs were transfused in patients with pre-existing anaemia (p< 0.001). Post-operative adverse events were more likely in patients with anaemia (p <0.001). In-hospital mortality was higher in patients with severe pre-operative anaemia (p =0.002). Conclusion: Pre-existing anaemia in non-cardiothoracic surgery patients is associated with more transfusions, a higher level of adverse outcomes and a higher in-hospital mortality. Using MCH and MCV as screening parameters helps to detect patients with an iron deficiency and start a patient blood management programme prior to surgery. This may help to reduce adverse outcomes after major surgery.