title: The impact of perioperative iron on the use of red blood cell transfusions in gastrointestinal surgery: a systematic review and meta-analysis.
abstract: Perioperative anemia is common, yet detrimental, in surgical patients. However, red blood cell transfusions (RBCTs) used to treat anemia are associated with significant postoperative risks and worse oncologic outcomes. Perioperative iron has been suggested to mitigate perioperative anemia. This meta-analysis examined the impact of perioperative iron compared to no intervention on the need for RBCT in gastrointestinal surgery. We systematically searched Medline, Embase, Web of Science, Cochrane Central, and Scopus to identify relevant randomized controlled trials (RCTs) and nonrandomized studies (NRSs). We excluded studies investigating autologous RBCT or erythropoietin. Two independent reviewers selected the studies, extracted data, and assessed the risk of bias using the Cochrane tool and Newcastle-Ottawa scale. Primary outcomes were proportion of patients getting allogeneic RBCT and number of transfused patient. Secondary outcomes were hemoglobin change, 30-day postoperative morbidity and mortality, length of stay, and oncologic outcomes. A meta-analysis using random effects models was performed. The review was registered in PROSPERO (CRD42013004805). From 883 citations, we included 2 RCTs and 2 NRSs (n = 325 patients), all pertaining to colorectal cancer surgery. Randomized controlled trials were at high risk for bias and underpowered. One RCT and 1 NRS using preoperative oral iron reported a decreased proportion of patients needing RBCT. One RCT on preoperative intravenous iron and 1 NRS on postoperative PO iron did not observe a difference. Only 1 study revealed a difference in number of transfused patients. One RCT reported significantly increased postintervention hemoglobin. Among 3 studies reporting length of stay, none observed a difference. Other secondary outcomes were not reported. Meta-analysis revealed a trend toward fewer patients requiring RBCT with iron supplementation (risk ratio, 0.66 [0.42, 1.02]), but no benefit on the number of RBCT per patient (weighted mean difference, -0.91 [-1.61, -0.18]). Although preliminary evidence suggests that it may be a promising strategy, there is insufficient evidence to support the routine use of perioperative iron to decrease the need for RBCT in colorectal cancer surgery. Well-designed RCTs focusing on the need for RBCT and including long-term outcomes are warranted.
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, Ontario, Canada; Division of Surgical Oncology, Sunnybrook Health Sciences Centre-Odette Cancer Centre, Toronto, Ontario, Canada; Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Hallet
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Asad
authors.initials: A
authors.lastname: Hanif
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Division of Clinical Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Jeannie
authors.initials: J
authors.lastname: Callum
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Ioulia
authors.initials: I
authors.lastname: Pronina
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Wallace
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Lavanya
authors.initials: L
authors.lastname: Yohanathan
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, Ontario, Canada; Division of General Surgery, Mount Sinai Hospital, Toronto, Ontario, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Robin
authors.initials: R
authors.lastname: McLeod
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, Ontario, Canada; Division of Surgical Oncology, Sunnybrook Health Sciences Centre-Odette Cancer Centre, Toronto, Ontario, Canada; Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. Electronic address: natalie.coburn@sunnybrook.ca.
authors.forename: Natalie
authors.initials: N
authors.lastname: Coburn
mesh_terms: D000740:Anemia / Q000601:surgery*; D017707:Erythrocyte Transfusion / Q000379:methods*; D004912:Erythrocytes / Q000166:cytology*; D005260:Female; D041981:Gastrointestinal Tract / Q000601:surgery; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000627:therapeutic use*; D008297:Male; D064887:Observational Studies as Topic; D059035:Perioperative Period; D016032:Randomized Controlled Trials as Topic; D014184:Transplantation, Homologous; D016896:Treatment Outcome
chemical_list: D006454:Hemoglobins; D007501:Iron
keywords: Anemia; Colorectal cancer; Iron; Perioperative; Surgery; Transfusion