In this meta-analysis, Fowler et al. investigated the impact of preoperative anaemia on postoperative outcomes. A total of 24 eligible studies including 949,445 cardiac and non-cardiac surgery patients were identified. According to the definitions of anaemia used by the authors of included studies, 39% of the patients were anaemic (in the 13 studies using the WHO definition of anaemia, the proportion of anaemic patients was 29.9%).

Preoperative anaemia was associated with increased short-term mortality after surgery (OR 2.90) as well as with an increased incidence of stroke (OR 1.28), acute kidney injury (OR 3.75) and infection (OR 1.93). Not surprinsingly, allogeneic red cell transfusion was more frequent in patients with preoperative anaemia (OR 5.04).

Although preoperative anaemia is partly related to co-morbidities and it remains unclear whether correcting preoperative anaemia can improve outcomes, the editors note that their findings emphasise the importance of anaemia and patient blood management.

– Elvira Bisbe