Unveiling the Correlation between Transferrin Saturation and Critically Ill COVID-19 Patients’ Outcomes: A Multicenter Cohort Study

Background: Critically ill patients with coronavirus disease 2019 (COVID-19) often have cytokine storms, manifested with elevated levels of proinflammatory biomarkers and hyperferritinemia. Systemic inflammation significantly limits the iron availability for erythropoiesis, which may disturb iron homeostasis and affect clinical outcomes. Thus, this study aimed to evaluate the impact of iron hemostasis on the clinical outcomes of critically ill patients with COVID-19. Materials and Methods: A multicenter, retrospective cohort study was conducted and included critically ill adult COVID-19 patients admitted to the intensive care units (ICUs) from March 2020 to July 2021. Patients were categorized based on transferrin saturation (TSAT) during their ICU stay (TSAT < 20% vs. TSAT ≥ 20%). The primary outcome was the in-hospital mortality, while other outcomes were considered secondary. Results: After propensity score matching (PSM) (1:1 ratio), 46 patients were included in the final analysis. In-hospital mortality was not statistically significantly different between the two groups (OR, 0.91; 95% CI, 0.29–2.87; P = 0.88). Patients with TSAT ≥ 20% had a longer mechanical ventilation duration (beta coefficient 0.11; 95% CI, −0.54–0.76; P = 0.19); however, it did not reach statistical significance. Moreover, the ICU length of stay (LOS) and hospital LOS were not statistically significant in patients with a TSAT ≥ 20%. Conclusion: Our results show no significant differences in clinical outcomes between patients with TSAT levels ≥20% and those with TSAT < 20%. Larger prospective studies are needed to verify these findings and evaluate the effect of iron correction on anemic patients’ outcomes.