Safety and efficacy of iron therapy on reducing red blood cell transfusion requirements and treating anaemia in critically ill adults: A systematic review with meta-analysis and trial sequential analysis

Abstract Purpose To evaluate the safety (risk of infection) and efficacy (transfusion requirements, changes in haemoglobin (Hb)) of iron therapy in adult intensive care unit (ICU) patients. Materials and methods We systematically searched seven databases for all relevant studies until January 2018 and included randomized (RCT) studies comparing iron, by any route, with placebo/no iron. Results 805 participants from 6 RCTs were included. Iron therapy, by any route, did not decrease the risk of requirement for a red blood cell (RBC) transfusion (Risk ratio (RR) 0.91, 95% CI 0.80 to 1.04, p  = 0.15) or mean number of RBCs transfused per participant (mean difference (MD) -0.30, 95% CI -0.68 to 0.07, p  = 0.15). Iron therapy did increase mean Hb concentration (MD 0.31 g/dL, 95% CI 0.04 to 0.59, p  = 0.03). There was no difference in infection (RR 0.95, 95% CI 0.79 to 1.19, p  = 0.44). Trial Sequential Analysis suggests that the required participant numbers to detect or reject a clinically important effect of iron therapy on transfusion requirements or infection in ICU patients has not yet been reached. Conclusion Iron therapy results in a modest increase in Hb. The current evidence is inadequate to exclude an important effect on transfusion requirements or infection.