Pre-operative haemoglobin levels and iron status in a large multicentre cohort of patients undergoing major elective surgery

Abstract

Pre-operative anaemia in patients undergoing major surgical procedures has been linked to poor outcomes. Therefore, early detection and treatment of pre-operative anaemia is recommended. However, to effectively implement a pre-operative anaemia management protocol, an estimation of its prevalence and main causes is needed. We analysed data from 3342 patients (44.5% female) scheduled for either: elective orthopaedic surgery (n = 1286); cardiac surgery (n = 691); colorectal cancer resection (n = 735); radical prostatectomy (n = 362); gynaecological surgery (n = 203) or resection of liver metastases (n = 122). For both sexes, anaemia was defined by a haemoglobin level < 130 g.l^-1 ; absolute iron deficiency by ferritin < 30 ng.ml^-1 (< 100 ng.ml^-1 , if transferrin saturation < 20% or C-reactive protein > 5 mg.l^-1 ); iron sequestration by transferrin saturation < 20% and ferritin > 100 ng.ml^-1 ; and low iron stores by transferrin saturation > 20% and ferritin 30-100 ng.ml^-1 . The overall prevalence of anaemia was 36%, with differences according to the type of surgery. Laboratory parameters allowing classification of iron status were available for 2884 patients. Among those with anaemia (n = 986), 677 (69%) were women, 608 (62%) presented with absolute iron deficiency, 101 (10%) with iron sequestration; and 150 (5%) with low iron stores. Iron status alterations were similar in women with haemoglobin < 130 g.l^-1 or < 120 g.l^-1 . For those who were not anaemic (n = 1898), corresponding figures were 656 (35%), 621 (33%), 165 (9%) and 518 (27%), respectively. Anaemia was present in one-third of patients undergoing major elective procedures. Over two-thirds of anaemic patients presented with absolute iron deficiency or iron sequestration. Over half of non-anaemic patients presented with absolute iron deficiency or low iron stores. We consider these data useful for planning pre-operative management of patients scheduled for major elective surgery.

Keywords: anaemia; iron deficiency; iron sequestration; iron stores; major surgery.