Discussion
Our results show that patients with COVID-19 pneumonia had iron
deficiency even they were young. And we speculate that iron deficiency
effects the lung aeration loss related to paranchimal infiltrations of
COVID-19. Our data indicates that iron deficiency is associated with
longer hospitalization, lower oxygenation, higher CRP and procalsitonin.
We found a significant effect of iron deficiency parameters on mortality
of COVID-19 pneumonia. Pre-existing iron deficiency may be a risk factor
for COVID-19 pneumonia and it’s severity. Since COVID-19 patients in our
study had a higher prevalence of comorbidities such as hypertension,
cardiovascular disease and diabetes mellitus; reduced tissue oxygenation
as a result of chronic inflammation may be the reason of iron
deficiency.
Bellmann-Weiler et al. (9) claimed anemia, specifically anemia of
inflammation is prevalent in patients with severe SARS-CoV-2 infection
and that anemia is associated with longer hospital stays, poor clinical
conditions and poor survival. Systemic inflammations are associated with
increased serum ferritin levels. Serum iron and TSAT decrease early
after infections, inhibiting iron availability to the pathogens (10,11).
Edeas M et al. (12) speculated that increased serum ferritin levels as a
result of COVID-19 related hyper-inflammation and increased ferritin
levels may lead to further tissue damage. It has been reported that
hyper-inflammation in association with altered iron homeostasis may play
a key role in pathogenesis of disease including viral infections (13).
Hyper-ferritinemia may be associated with iron toxicity from damaged
tissue releasing free iron. There is no consensus to exclude this
possibility.
Iron metabolism and anemia may play an important role in multiple organ
dysfunction syndrome in COVID-19. A meta-analysis suggested that
hemoglobin and ferritin levels vary according tot the severity of
COVID-19 as well as age, gender and presence of comorbidity. The mean
diference in serum ferritin was higher in severe COVID-19 compared to
moderate cases. From seven observational studies and 717 individuals,
the mean difference in RBC count was lower, while RDW was higher in
patients with severe COVID-19 (14).
Huang et al. (15) reported reduction in hemoglobin levels in 38.2% of
hospitalized COVID-19 patients. Hemoglobin concentration is one of the
most important determinants of the oxygen-carrying capacity of the
blood. COVID-19 patients, could sufer from a decreased capability of
hemoglobin to support the increased peripheral tissue demands for oxygen
due to the hyper-metabolic states during infection. Our results supports
this idea since hemoglobin of patients with COVID-19 was significantly
lower than the patients with non-COVID-19 pneumonia.
Alipour R et al. (16) found out that serum iron levels were lower than
normal range of patients with mild, modarate and severe COVID-19
infection. They claimed that serum iron levels of ICU admitted patients
were significantly lower than others. Based on the results, they
spaculated that the severity of respiratory symptoms might depend on low
serum iron. Our results showed that dyspnea of patients with COVID-19
infection. In our study there was an inverse relation between iron
deficiency parameters (RET-He, TSAT, iron) and radiological
infiltrations, hosptalization days and inflamatory parameters (CRP, PCT)
of COVID-19 patients. In the otherwise Cavezzi at al. (17) mentioned
about the possible role of hemoglobin denaturation and tissue iron
overload in COVID-19; potential adjuvant therapeutic interventions in a
review article.
In a study by Li et al. (18) ferritin was significantly higher in severe
patients. Shah et al. (19) reported no significant differences in serum
ferritin levels and transferrin saturation between patients with
non-severe and severe hypoxemia. They reported significantly lower
levels of serum iron in patients with severe hypoxemia. In our study,
there was not a significant difference in ferritin levels between
COVID-19 and non-COVID-19 pneumonia but the ferritin level of severe
COVID-19 pneumonia was higher.
Virus-connected iron metabolism is one of the topics have to be
investigated for the development of therapeutic strategies for COVID-19.
Which one might be used to treat COVID-19 infections; iron replacement
treatment or iron chelators? This subject is still controversial and has
to be determined in future studies.