Klein and colleagues performed a national audit in the UK in order to evaluate the incidence and clinical impact of preoperative anaemia in patients who underwent cardiac surgery between 2010 and 2012. The audit included more than 19 000 patients from 12 cardiac surgery centres, of whom 31% had preoperative anaemia.

Interestingly, the incidence of anaemia showed a regional variation, ranging from 23% to 45%, irrespective of the demographic patient profile per centre. Patients with anaemia had a higher risk for blood transfusion (OR 2.75, 95% CI 2.55-2.95; P < 0.001) and mortality (OR 1.42, 95% CI 1.18-1.71; P < 0.001). In addition to anaemia, preoperative haemoglobin levels per se were associated with clinical outcome. This audit confirms that the presence of preoperative anaemia in cardiac surgery is common in the UK, and associated with unfavourable outcome. The authors attribute the strong regional variability in the incidence of preoperative anaemia to differences in the socio-economic profile of patients, but cannot exclude a centre-specific approach with respect to preoperative haemoglobin optimisation in patients undergoing cardiac surgery. This audit provides a strong rationale to initiate prospective studies focusing on the treatment of preoperative anaemia in order to improve perioperative outcome. – Christa Boer