Exploring hematological alterations in COVID-19 patients

By Shanet Susan AlexReviewed by Aimee MolineuxJan 26 2022

In a recent study posted to the journal Hematology, Transfusion, and Cell Therapy, researchers determined whether some hematological parameters can be used as biomarkers to facilitate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis and prognosis evaluation.

Introduction

Coronavirus disease 2019 (COVID-19) manifests with fatigue, fever, dyspnea, and non-productive cough. Studies also show that SARS-CoV-2 patients also demonstrated hematological findings such as lymphopenia, leukopenia, and hypercoagulability with a high level of D-Dimers.

However, sufficient information regarding the frequent hematological alterations in COVID-19 patients and their use in the diagnosis, prognosis evaluation, or mortality risk is not yet available.

The study

In the present study, the researchers determined:

• the frequency of hematological changes in COVID-19 patients, and their relevance in determining the prognosis of the disease,
• any particular pattern in hematological alterations in the initial hemogram of COVID-19 patients who were later admitted to the ICU and also those who died within a month of COVID-19 diagnosis, and
• the significance of lymphocyte/platelet index in predicting COVID-19-related ICU admission and mortality risk.

Individuals who were tested SARS-CoV-2 positive and had a hemogram test between March 15-April 15, 2020, were included in the study. Among the patient's hemograms dated 48 hours before and after a positive SARS-CoV-2 test, those with the lower time interval from the positive test were selected for the study.

The following data was obtained from 274 patients in two Portuguese public hospitals: socio-demographic and analytical data at initial hospital admission, hemogram parameters during intensive care unit (ICU) admission, and data collected from survived patients during SARS-CoV-2 disease follow-up. The data were evaluated using appropriate statistical tests.

Findings

 The findings frequently found in SARS-CoV-2 patients eventually admitted to ICU were as follows: nearly 63.14% had lymphopenia, 50.36% had higher LDH levels, 46.0% had anemia, and 48.2% had low erythrocytes counts. Interestingly, leukopenia was not frequently found to be associated with a risk of ICU admission for COVID-19 patients in the present study.

Anemia and elevation in LDH levels were more frequently found in elderly patients who were later admitted to the ICU, and the median age of the study population was 75 years.

The pattern of hematological alterations for patients eventually admitted in the ICU during their initial hemogram were elevation in neutrophils, leukocytes, platelet counts, and a decrease in lymphocyte counts. These patients were associated with a higher risk of lengthy hospital stay and admission to the ICU.

Similarly, those with a reduction in hemoglobin, median globular volume, and erythrocyte values during their initial hemogram have a high risk of later ICU admission. Further, a high level of LDH during hospital admission will increase the risk of eventual ICU admission.

The study further demonstrated the relationship between high platelet count, high cytokine storm, worse prognosis, and lengthy hospital stay. Patients admitted to the ICU had a higher level of platelet counts and were mostly aged around 67 years. Two factors that played a significant role in ICU admission of the COVID-19 patients were comorbidities and age.

Additionally, the gender and lymphocyte/platelet index did not demonstrate any statistical significance in predicting COVID-19-associated ICU admission.

A high risk for COVID-19-associated mortality was found in elderly patients, males, and those with high neutrophil counts, lymphocyte counts, and neutrophil-lymphocyte ratio. Likewise, low platelet counts, mean corpuscular hemoglobin concentration (MCHC), and erythrocytes values at hospitalization increased the risk for COVID-19-associated mortality.

Conclusions

The study findings indicated that some hematological alterations that occur during COVID-19-related hospital admission were associated with an increase in the risk of COVID-19-associated ICU admission and mortality.

COVID-19-related ICU admission is associated with high leukocytes, neutrophils, platelet counts, and reductions in lymphocyte counts in SARS-CoV-2 patients at hospital admission.

Low levels of hemoglobin, erythrocytes, and median globular volume during hospitalization were also associated with a high risk of COVID-19-related ICU admission. Further, high levels of LDH in SARS-CoV-2 patients during hospital admission are also implicated in COVID-19-related ICU admission.

The age, gender, lymphocyte, platelets, neutrophil, erythrocytes, cell hemoglobin concentration mean (CHCM) values, and the neutrophil-lymphocyte ratio was independently associated with COVID-19-related mortality risk.

The study findings were in line with previous studies stating frequent lymphopenia in SARS-CoV-2 patients, the association of higher platelet count and cytokine storm, the higher neutrophil count association with higher mortality rate, and higher LDH levels and anemia in the older SARS-CoV-2 patients.

In contrast, this study did not find frequent leukopenia in SARS-CoV-2 patients, or statistically significant variations in lymphocyte/platelet index predicting COVID-19-associated ICU admission. Also, the ICU-admitted patients in this study were younger by almost nine years than the previous findings.

Overall, since the hematological data at hospital admission can predict SARS-CoV-2-related ICU admission and mortality risk, the researchers recommended using these data as the basis for patient prognosis evaluation and clinical decisions inCOVID-19 patients.