Iron deficiency and preoperative anaemia in patients scheduled for elective hip- and knee arthroplasty - an observational study

Abstract

Background and objectives: Preoperative anaemia is prevalent in elderly patients scheduled for major orthopaedic surgery and is associated with increased transfusion risk and postoperative morbidity. New guidelines recommend preoperative correction of anaemia and iron deficiency in all patients with a Hb < 13 g/dl. However, iron deficiency and other causes of preoperative anaemia in hip- (THA) and knee (TKA) arthroplasty are only sparsely studied.

Materials and methods: Preoperative Hb and iron status were prospectively collected from 882 unselected elective fast-track THA/TKA patients and analysed according to both WHO anaemia criteria (Hb < 12 g/dl females, <13 g/dl males) and Hb < 13 g/dl for both genders. Iron deficiency (ID) and other possible anaemia causes were classified by ferritin, transferrin saturation, P-cobalamin, P-folate, C-reactive protein and creatinine.

Results: Ninety-five (10·8%) and 243 (27·6%) of the study population were WHO anaemic or had a Hb < 13 g/dl, respectively. Transfusion was more common in anaemic vs. non-anaemic patients 43 vs. 13%; (P < 0·001), and in patients with Hb < 13 g/dl vs. Hb > 13 g/dl 28 vs. 11% (P < 0·001). 154 (17·5%) of all patients had ID, and ID was the most common cause of anaemia with a prevalence of 41% in WHO anaemic patients and 33% in patients with Hb < 13 g/dl. A further 19 (20%) and 46 (19%) patients, respectively, had evidence of iron sequestration.

Conclusion: Anaemia is prevalent prior to THA and TKA with iron deficiency as the most common and reversible cause.

Keywords: anaemia; arthroplasty; iron deficiency; patient blood management.