Serum Iron Level as a Potential Predictor of Coronavirus Disease 2019 Severity and Mortality: A Retrospective Study

Abstract

Background: Various types of pulmonary diseases are associated with iron deficiency. However, information on iron status in coronavirus disease 2019 (COVID-19) is scarce.

Methods: This study included 50 hospitalized patients with confirmed COVID-19. The role of serum iron in predicting severity and mortality of COVID-19 was evaluated.

Results: The most common symptoms of COVID-19 patients in this study were cough (82%), fever (64%), and chest distress (42%). Of the 50 patients, 45 (90%) patients had abnormally low serum iron levels (<7.8 μmol/L). The severity of COVID-19 was negatively correlated with serum iron levels before and after treatment and was positively correlated with C-reactive protein, serum amyloid A, D-dimer, lactate dehydrogenase, urea nitrogen, and myoglobin levels. Decreased serum iron level could predict the transition of COVID-19 from mild to severe and critical illness. Seven (53.8%) patients with a lower serum iron level after treatment in the critical group had died. There was a significant difference in posttreatment serum iron levels between COVID-19 survivors and nonsurvivors.

Conclusions: Serum iron deficiency was detected in the patients with COVID-19. The severity and mortality of the disease was closely correlated with serum iron levels. Low serum iron concentration was an independent risk factor for death in COVID-19 patients.

Keywords: coronavirus disease 2019; mortality; prediction; serum iron; severity.

Figure 1.

Correlation between the type of coronavirus 2019 (COVID-19) and other laboratory parameters. The severity of COVID-19 was negatively correlated with serum iron levels before and after treatment and was positively correlated with C-reactive protein (CRP), serum amyloid A (SAA), D-dimer, lactate dehydrogenase (LDH), urea nitrogen, and myoglobin levels. Pretreatment serum iron levels were negatively correlated with CRP and SAA levels.

Figure 2.

Receiver-operating characteristics curve analysis for predicting the severity of coronavirus 2019 (COVID-19). (A) Lymphocyte count, percentage of lymphocytes, and pretreatment serum iron levels could be used to predict the severity of COVID-19. (B) Lymphocyte count, percentage of lymphocytes, and posttreatment serum iron levels could be used to predict the mortality of COVID-19.

Figure 3.

Chest computed tomography (CT) images of patients with coronavirus 2019 (COVID-19). (A) Transverse chest CT images showed bilateral ground-glass opacity from 3 mild patients 1 week after symptom onset and 11 days after admission. (B) Chest CT images showed subsegmental areas of consolidation from another 3 severe patients 1 week after symptom onset and 11 days after admission. (C) Extensive bilateral pulmonary changes of consolidation were found in the lungs of critical patients. (D) Patients who died in the critical group had more severe lesions in bilateral lungs than those in the mild and severe groups.