Discussion
In the last one year, the prevalence of COVID-19 infection has increased
on a daily basis among all over the world. As a result, determining the
severity and mortality of the disease is necessary in order to minimize
the pandemic’s spread. Many studies have identified clinical features of
COVID-19 patients, including epidemiological, clinical, laboratory,
radiological, and treatment results. Laboratory findings at the time of
admission to hospital were shown as important differences between severe
and non-severe patients. In addition, the role of several laboratory
parameters in the evaluation of the disease severity of COVID-19 in
hospitalization has been revealed in some previous studies. (3, 7-9). In
this study, our aim was to evaluate whether hematological parameters and
ferritin level predicted the mortality of patients and whether they had
an effect on the duration of hospitalization in patients treated by
hospitalization.
It has been stated that as the age of infected patients rises, so does
the mortality rate, with the crude mortality rate in people over 80
years old being 21.9 percent (4). Multivariate analysis showed that old
age and high concentration of LDH were independent predictors of poor
prognosis in a retrospective study (10). As a consequence, identifying
and diagnosing serious or critical patients is vital. This study showed
that the patients’ median age was 70 years, with a range of 19 to 98
years. In a study comparing moderate and severe patient groups, no
significant difference was found in terms of gender (4). It was observed
that the number of female patients hospitalized was higher than the
number of male patients in this study.
However, the majority of patients
who did not respond to treatment and had mortality were males. In
patients who responded to the treatment and could be discharged, the
duration of hospitalization was observed to be longer in women.
According to a meta-analysis report, COVID-19 severity is associated
with higher WBC counts and lower lymphocyte, CD4+ T cell, and CD8+ T
cell counts in COVID-19 patients. (11). The decrease in lymphocyte count
appears to be directly proportional to the severity of COVID-19
infection. Wang et al. reported that leukocyte, neutrophil, NLR,
platelet-to-lymphocyte ratio in the severe group were significantly
higher than those in the moderate group; additionally the study reported
that lymphocyte, eosinophile, and hemoglobin in the severe group were
significantly lower than those in the moderate group (4). In our study,
leukocyte, neutrophil and NLR
levels were found to be statistically significantly higher in patients
with mortality. At the same time, hemoglobin, lymphocyte, eosinophil and
albumin levels were found to be statistically significantly lower in
patients with mortality. This may be due to long-term infection and
hypoxia, which allows the bone marrow to compensate by producing more
granulocytes. SARS-CoV-2 can continue to invade more lymphocytes,
proliferate, and cause lymphocytes to die or become exhausted when they
enter the spleen and other immune organs, resulting in severe
lymphopenia in patients with mortality (4). Fan et al. reported that
mild thrombocytopenia and leukopenia were found in some COVID-19
positive patients at first admission. Additionally, they showed that on
admission; older age, lymphopenia and raised LDH were associated with
intensive care unit admissions (12). In previous years Xu et al.
reported that thrombocyte counts are substantially low in pneumonia
patients, and this drop is directly proportional to the patients’
clinical status(13).
Henry et al. reported that both serious and fatal COVID-19 patients had
elevated biomarkers of cardiac and muscle damage. Patients who deceased
due to disease had substantially elevated cardiac troponin levels at the
time of diagnosis. When these results are coupled with substantial
elevations in liver enzymes (alanine aminotransferase and aspartate
aminotransferase), renal biomarkers (blood urea nitrogen, creatinine),
and coagulation steps, an image of multiorgan failure appears in
patients who experience the extreme type of the disease. In one study,
increased serum ferritin levels were reported among patients who did not
survive compared with patients who survived(14). This important result
was also observed in another meta-analysis study among severe and
non-survival patients with COVID-19 infection(15). Similarly, in our
study, ferritin values were found to be significantly higher in patients
with mortality on admission to the hospital. Among other biochemical
parameters evaluated during hospital admission, ALT, urea, uric acid,
CK, D-dimer and LDH were found to be statistically significantly higher
in patients with mortality. On the other hand, it was observed that the
albumin value at admission in these patients was statistically
significantly lower than the patients who were discharged.
Our study had some limitations. First, this study was retrospective.
Second all patients included in the study consisted of patients who were
hospitalized due to their symptoms. Outpatients with mild symptoms were
not included in the study and blood values were not known at the time of
diagnosis. However, in this study, it has seen that it is important to
associate the onset of symptoms (days of illness) with hematological
parameters. In conclusion,
multiple laboratory parameters can
be related to the severity and mortality of COVID-19 infection and
should be screened and assessed on a regular basis as the pandemic
progresses. WBC count, neutrophil, lymphocytes, NLR, eosinophil,
platelet count, ferritin, ALT, urea, uric acid, CK, albumin, D-dimer,
and LDH were among the parameters tested. This study indicates that
by using the most simple and
routine hematological tests at the time of COVID-19 diagnosis, it may be
possible to predict a patient’s prognosis. This will help patients
receive early clinical care, reducing patient mortality and aiding in
the control and prevention of the outbreak.