Does Parenteral Iron Increase the Risk of Infection in Patients with Gastrointestinal Cancer? A Systematic Review and...

Background: Parenteral iron is increasingly used to treat iron deficiency anaemia in patients with gastrointestinal cancer, particularly in the perioperative setting. However, concerns persist that intravenous iron could increase the risk of infection. We conducted a systematic review and meta-analysis to evaluate infectious complications and other relevant clinical outcomes after parenteral iron in gastrointestinal cancer. Methods: Embase, MEDLINE, CENTRAL and Scopus were searched from database inception to 20 February 2026, with additional records identified through citation searching. Comparative studies were eligible if they included adults with gastrointestinal cancer and compared parenteral iron with oral iron, placebo, no iron or standard care. Randomised and non-randomised comparative studies were included. The primary outcome was infection or infective complications. Secondary outcomes included length of hospital stay, hospital readmission and short-term mortality. Risk ratios (RRs) and mean differences (MDs) were pooled using random-effects models. Results: The search identified 2771 records. After removing 458 duplicates, 2313 records were screened, and 210 full texts were assessed. Fourteen comparative studies were included: four randomised controlled trials and ten non-randomised studies. Nine studies contributed to the primary infection analysis, including 899 patients receiving parenteral iron and 768 controls. Infection occurred in 126 patients in the parenteral iron group and 104 controls. Parenteral iron was not associated with an increased risk of infection (RR 1.07, 95% CI 0.71-1.62; p = 0.754; I² = 57%). Restriction to randomised trials also showed no significant increase in infection risk (RR 1.17, 95% CI 0.56-2.43). Thirteen studies reported length of stay, with no meaningful difference between groups (MD: -0.05 days, 95% CI: -0.66 to 0.57). Four studies reported hospital readmission, with no significant difference between parenteral iron and control (RR 0.76, 95% CI 0.35-1.64; p = 0.480; I² = 0%). Mortality analyses were event-limited, with no significant difference in 30-day mortality (RR 0.49, 95% CI 0.09-2.61) or 90-day mortality (RR 0.69, 95% CI 0.35-1.36). Conclusions: In patients with gastrointestinal cancer, parenteral iron was not associated with increased infection risk, prolonged hospital stay, higher readmission or increased short-term mortality. These findings provide reassuring evidence regarding the perioperative safety of parenteral iron, although confidence in the estimate is limited by observational evidence and heterogeneous definitions of infection.