Real-world results of the implementation of preoperative anaemia clinic with intravenous iron therapy for treating iron-deficiency anaemia: a propensity-matched case-control study

Hairil R Abdullah; Tanakorn Thamnachit; Ying Hao; Wan Yen Lim; Li Ming Teo; Yilin Eileen Sim

doi:10.21037/atm-20-4942

Real-world results of the implementation of preoperative anaemia clinic with intravenous iron therapy for treating iron-deficiency anaemia: a propensity-matched case-control study

Ann Transl Med. 2021 Jan;9(1):6. doi: 10.21037/atm-20-4942.

Authors

Hairil R Abdullah¹, Tanakorn Thamnachit¹, Ying Hao², Wan Yen Lim¹, Li Ming Teo¹, Yilin Eileen Sim¹

Affiliations

¹ Department of Anaesthesiology, Singapore General Hospital, 169608, Singapore.
² Health Services Research Centre (HSRC), Singapore Health Services, 169608, Singapore.

Abstract

Background: Preoperative anaemia is associated with blood transfusion and longer hospital length of stay. Preoperative iron deficiency anaemia (IDA) can be treated with oral or intravenous (IV) iron. IV iron can raise haemoglobin faster compared with oral iron. However, its ability to reduce blood transfusion and length of stay in clinical trials is inconclusive. This study aims to compare blood transfusion and hospital length of stay between anemic patients who received preoperative IV iron versus standard care, after implementation of a protocol in 2017 to screen patients for preoperative IDA, and its treatment with IV iron.

Methods: Retrospective before-after cohort study comparing 89 patients who received IV iron preoperatively in 2017, with historic patients who received oral iron therapy (selected by propensity score matching (PSM) from historic cohort of 7,542 patients who underwent surgery in 2016). Propensity score was calculated using ASA status, age, gender, surgical discipline, surgical risk and preoperative haemoglobin concentration. Both 1:1 and 1:2 matching were performed as sensitivity analysis.

Results: After PSM, there was no statistically significant difference in distribution of preoperative clinical variables. There was no significant difference in proportion of cases requiring transfusion nor a difference in average units transfused per patient. IV iron cohort stayed in hospital on average 8.0 days compared to non-IV iron cohort 14.1-15.1 days (P=0.006, P=0.013 respectively). Average time from IV iron therapy to surgery was 10.5 days.

Conclusions: Preoperative IV iron therapy for patients with IDA undergoing elective surgery may not reduce perioperative blood transfusion, but this could be due to the short time between therapy and surgery. Implementation of IV iron therapy may reduce hospital length of stay compared to standard care for anemic patients, although this may be enhanced by concomitant improvement in perioperative care.

Keywords: Anaemia; hospital length of stay; intravenous iron; perioperative blood transfusion; surgery.