Prevalence of iron deficiency and red blood cell transfusions in surgical patients

While iron deficiency (ID) is the most common cause of anaemia, little is known about the prevalence and type of ID in preoperative surgical patients. The aims of the present study were to investigate the prevalence and types of ID in a large cohort of surgical patients, and how these are related to perioperative blood use after correction for confounders such as haemoglobin level.

Data were retrospectively extracted from electronic case records of all patients who underwent elective surgery between September 2016 and November 2017 (n = 2711). Iron parameters, haemoglobin and details of perioperative red cell transfusions were collected.

Of 2711 patients, 618 (22.8%) were iron deficient (= transferrin saturation [TSAT] < 16%) preoperatively, 173 (6.4% of the cohort) had an absolute iron deficiency (AID; TSAT < 16% and ferritin < 30 μg/L) and 445 (16.4%) had functional/mixed ID (TSAT < 16% and ferritin ≥ 30 μg/L). Corrected for Hb level, iron-deficient patients received significantly more red cell units than patients without ID (p = 0.026). AID was not associated with a significantly higher incidence of transfusions (7.5% of patients transfused; p = 0.12 after correction for Hb) than patients without ID, whereas patients with functional/mixed deficiency did receive significantly more transfusions (6.1%; p = 0.021) as compared to patients without ID (1.7%).

Preoperative ID, in particular the functional/mixed type, was associated with a higher risk of receiving perioperative red cell transfusions as compared to patients without ID. Adequately treating ID might, therefore, reduce the need for perioperative red cell transfusions.