Pre-operative iron increases haemoglobin concentration before abdominal surgery: a systematic review and meta-analysis of randomized controlled trials

Colorectal Unit, Addenbrooke's Hospital, Cambridge NHS Foundation Trust, Cambridge, UK. jeremy.meyer@hcuge.ch. Division of Digestive Surgery, University Hospitals of Geneva, Geneva, Switzerland. jeremy.meyer@hcuge.ch. Medical School, University of Geneva, Geneva, Switzerland. jeremy.meyer@hcuge.ch. University of Perugia, Perugia, Italy. Hospital of San Benedetto del Tronto, Marche, Italy. Division of Digestive Surgery, University Hospitals of Geneva, Geneva, Switzerland. Medical School, University of Geneva, Geneva, Switzerland. Colorectal Unit, Addenbrooke's Hospital, Cambridge NHS Foundation Trust, Cambridge, UK.

Scientific reports. 2022;12(1):2158
PICO Summary

Population

Patients undergoing major abdominal surgery (4 studies, n= 651).

Intervention

Pre-operative iron.

Comparison

Placebo or usual care.

Outcome

Mean difference in haemoglobin concentration between patients with pre-operative iron and patients without pre-operative iron was of 0.81 g/dl. Pre-operative iron did not lead to reduction in the incidence of peri-operative blood transfusion in terms of risk difference (RD) or pooled relative risk (RR), (RD: - 0.13, RR: 0.57).
Abstract
Professional surgical societies recommend the identification and treatment of pre-operative anaemia in patients scheduled for abdominal surgery. Our aim was to determine if pre-operative iron allows correction of haemoglobin concentration and decreased incidence of peri-operative blood transfusion in patients undergoing major abdominal surgery. MEDLINE, Embase and CENTRAL were searched for RCTs written in English and assessing the effect of pre-operative iron on the incidence of peri-operative allogeneic blood transfusion in patients undergoing major abdominal surgery. Pooled relative risk (RR), risk difference (RD) and mean difference (MD) were obtained using models with random effects. Heterogeneity was assessed using the Q-test and quantified using the I(2) value. Four RCTs were retained for analysis out of 285 eligible articles. MD in haemoglobin concentration between patients with pre-operative iron and patients without pre-operative iron was of 0.81 g/dl (3 RCTs, 95% CI 0.30 to 1.33, I(2): 60%, p = 0.002). Pre-operative iron did not lead to reduction in the incidence of peri-operative blood transfusion in terms of RD (4 RCTs, RD: - 0.13, 95% CI - 0.27 to 0.01, I(2): 65%, p = 0.07) or RR (4 RCTs, RR: 0.57, 95% CI 0.30 to 1.09, I(2): 64%, p = 0.09). To conclude, pre-operative iron significantly increases haemoglobin concentration by 0.81 g/dl before abdominal surgery but does not reduce the need for peri-operative blood transfusion. Important heterogeneity exists between existing RCTs in terms of populations and interventions. Future trials should target patients suffering from iron-deficiency anaemia and assess the effect of intervention on anaemia-related complications.
Study details
Study Design : Systematic Review
Language : eng
Additional Material : Correction in: ‘Scientific Reports’ (2022), PMID: 35414647, 12(1): 6084, DOI: <a href="http://dx.doi.org/10.1038/s41598-022-10305-w">http://dx.doi.org/10.1038/s41598-022-10305-w</a>
Credits : Bibliographic data from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine