The efficacy of intravenous iron for treatment of anemia before cardiac surgery: An updated systematic review and meta-analysis with trial sequential analysis

Abstract

Background Preoperative anemia is common in patients undergoing cardiac surgery with various etiologies, among which iron deficiency is the leading cause. However, the benefit of intravenous (IV) iron for the treatment of anemia before cardiac surgery is uncertain. This updated meta-analysis aimed to evaluate the efficacy of IV iron in adult cardiac surgery patients with preoperative anemia. Methods This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched Embase, PubMed and the Cochrane Central Register of Controlled Trials to identify eligible randomized controlled trials (RCTs) and observational studies. Quality was assessed using the Cochrane Collaboration risk of bias tool and Newcastle–Ottawa scale, and the strength of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) criteria. Trial sequential analysis was performed on the primary outcome (transfusion rate) to confirm whether firm evidence was reached. Results Six RCTs (936 patients) and 5 observational studies (1350 patients) were included in this meta-analysis. The IV iron group and the control group were comparable in terms of transfusion rate [55.1% vs 60.9%, risk ratio (RR) = 0.91, 95% confidence interval (CI) 0.81–1.03, P = 0.13, low quality]. There were no significant differences in units transfused per patient, ICU stay and hospital length of stay between the two groups. And pooled data showed a benefit of IV iron compared to the control group on mortality (2.76% vs 3.75%, RR = 0.58, 95% CI 0.36–0.95, P = 0.03, moderate quality) and no mortality reduction existed when including only RCTs. Conclusions This meta-analysis suggested that IV iron treatment for patients with anemia before cardiac surgery did not reduce the transfusion requirement (low quality), but it was associated with decreased mortality (moderate quality). More large-scale, high-quality randomized clinical trials are warranted to confirm or refute our findings. PROSPERO registry reference: CRD42022331875.

A patient blood management perspective on Anemia in the obese patient journey

“…Recent studies have shown conflicting evidence. In a meta-analysis evaluating 936 patients with anemia in the preoperative setting for cardiovascular surgery, IV iron did not reduce the transfusion requirements but was associated with decreased mortality (62). On the other hand, the PREVENT trial, found no difference between groups in terms of red cell transfusion and 30-day mortality, despite observing a beneficial effect on the Hb in the iron group.…”

Examining Bleeding Risk, Transfusion-related Complications, and Strategies to Reduce Transfusions in Lung Transplantation

“…Preoperative anemia, vitamin, and iron deficiency should be corrected preoperatively, if possible. 34,35 Although of some benefit in cardiac surgery, consideration of intravenous iron therapy to improve hemoglobin levels 36 is not well established or studied in lung transplantation. Erythropoietin has not been well studied in lung transplantation, with limitations including an unknown surgery date and cost of the drug relative to the time to clinical benefit.…”

Iron as an emerging therapeutic target in critically ill patients

“…Additionally, blood transfusions may lead to the release of free hemoglobin and free iron as a result of hemolysis [ 6 ]. On the other hand, the benefits of intravenous iron supplementation for anemia treatment in critically ill patients are still controversial [ 42 , 43 ]. Hence, while a general positive correlation between anemia and iron content can be acknowledged, this relationship becomes more contentious when considering NBTI.…”