European Journal of Cardiovascular Medicine

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in late 2019 and rapidly escalated into a global pandemic, significantly impacting healthcare systems worldwide [1]. The disease presents with a wide range of clinical manifestations, from asymptomatic infection and mild upper respiratory illness to severe pneumonia, acute respiratory distress syndrome (ARDS), multiorgan failure, and death [2,3]. Identifying laboratory parameters that predict disease severity and progression is crucial for the early triage and management of patients.

Hematological and biochemical markers have been increasingly investigated for their role in assessing the clinical status and prognosis of COVID-19 patients. Notably, parameters such as total leukocyte count (TLC), neutrophil-to-lymphocyte ratio (NLR), and lymphocyte percentage have been reported to correlate with disease severity [4,5]. Elevated NLR has emerged as a significant prognostic marker, reflecting the imbalance between innate and adaptive immune responses [6]. Similarly, abnormalities in liver function tests (LFTs), including raised transaminases, hypoalbuminemia, and elevated lactate dehydrogenase (LDH), have been associated with poor outcomes, likely indicating systemic inflammation or hepatic involvement [7,8].

Multiple studies have shown that ICU-admitted COVID-19 patients tend to exhibit marked hematological derangements and biochemical abnormalities compared to those managed in general wards [9,10]. Furthermore, gender and age differences may influence immune response and biochemical alterations, possibly affecting disease course and outcomes [11]. Given the significance of these findings, the present study aims to retrospectively evaluate the hematological and biochemical profiles of COVID-19 positive patients admitted to a tertiary care hospital. By comparing these parameters between ICU and Non-ICU admissions and across genders, we hope to provide insights into the clinical utility of routine laboratory tests in stratifying disease severity and aiding management decisions.

Study Design and Setting

This was a Retrospective Observational Study conducted at the Dept of Pathology, Central Laboratory, RGSSH (OPEC), RIMS, Raichur a tertiary care institute, analyzing medical records of patients who were tested positive for COVID-19 and were admitted between June 2021 to May 2022.

Study Population

A total of 477 COVID-19 positive patients confirmed by RT-PCR were included in the study. Patients of all age groups and both genders were included. Patients with incomplete medical records or those referred from other hospitals after treatment were excluded.

Data Collection

• Data was retrieved from the laboratory information system (LIS). The following information was extracted:
• Demographic details: Age and Gender.
• Clinical data: Place of admission (ICU or Non-ICU).
• Hematological parameters: Total Leukocyte Count (TLC), Neutrophil (%), Lymphocyte (%), Monocyte (%), Eosinophil (%), Erythrocyte Sedimentation Rate (ESR), and Neutrophil-to-Lymphocyte Ratio (NLR).
• Biochemical parameters

Liver function parameters (LFTs): Total Bilirubin, Direct Bilirubin, SGOT (AST), SGPT (ALT), Alkaline Phosphatase (ALP), Total Protein, Albumin, Globulin, and Lactate Dehydrogenase (LDH).

Data Analysis

• Patients were grouped based on gender, age, and place of admission (ICU vs Non- ICU)
• Descriptive statistics were used to summarize the data. Frequencies and percentages were reported for categorical variables, while mean’s and standard deviations were calculated for continuous variables.
• Comparative analysis of hematological and biochemical parameters was performed between ICU and Non-ICU patients, and between male and female patients using independent sample t-tests.
• A p-value < 0.05 was considered statistically significant.

Ethical Considerations

The study was approved by the Institutional Ethics Committee. Since this was a retrospective study utilizing anonymized patient data, individual informed consent was waived.

Table 1: Distribution of study participants based on Gender,

Among the 477 persons studied 186 (39%) were females and 291 (61%) were males.

Table 2: Distribution of study participants based on Age group.

Among the 477 persons studied 29 (6.1%) were belonging to the age group of 1- 20 years, 142 (29.8%) were aged 21-40 years, 217 (45.5%) were aged 41- 60 years. 83 (17.4%) were aged between 61 -80 years and only 6 (1.3%) were aged above 80 years

Table 3: Distribution of study participants based on place of admission/outcome,

Among the studied population 214 (44.9%) were in admitted in ICU and 263 (55.1%) were admitted in the Non- ICU ward .

Table 4: Comparison of Blood parameters with the admission outcome.

  There was statistically significant higher NLR ratio, TLC, Neutrophil count in ICU patients compared to Non-ICU patients, whereas Lymphocytes count was lower in ICU patients compared to Non-ICU patients. There was a statistically significant lower monocyte count in those admitted in ICU compared to those admitted in Non- ICU ward. There was no statistically significant difference in ESR level with respect to admission or outcome.

Table 5: Comparison of LFT parameters with the admission outcome

 There was no statistically significant difference in levels of various LFT function tests with the admission outcome.

Table 6: Comparison of Blood parameters with the gender.

          There was no statistically significant difference in levels of various blood parameters with the gender.

Table 7: Comparison of LFT parameters with the gender.

          There was no statistically significant difference in the levels of various LFT function tests with the gender.

The current study evaluated the hematological and biochemical parameters in 477 , COVID-19 positive patients to explore their association with clinical severity and outcomes. A significant proportion of the patients were male (61%), consistent with global data suggesting a higher incidence and severity of COVID-19 in males [1,2].

The age distribution revealed that the majority of patients belonged to the 41–60 years age group, which aligns with findings by Chen et al. and Guan et al., where middle-aged and elderly populations were more frequently and severely affected [3,4]. This may be attributed to age-related immunosenescence and the presence of comorbidities.

A total of 44.9% of patients required ICU admission, suggesting a considerable burden of moderate-to-severe disease in the Cohort. Hematological analysis showed a significantly elevated Neutrophil-to-Lymphocyte Ratio (NLR), Total Leukocyte Count (TLC), and neutrophil percentage in ICU patients, while lymphocyte percentage and monocyte counts were significantly lower. These findings are in line with previous studies, which have demonstrated that elevated NLR and leukocytosis are associated with disease severity and poor outcomes in COVID-19 [5,6]. Lymphopenia, a hallmark of severe COVID-19 infection, indicates impaired adaptive immunity and has been reported as an early marker of severity [7,8].

The absence of significant differences in eosinophil counts and ESR, between ICU and Non-ICU groups is similar to findings from other retrospective studies, which suggest that these markers are not reliable predictors of COVID-19 severity [9]. Liver function test (LFT) parameters, including bilirubin, transaminases, and albumin levels, did not differ significantly between ICU and Non-ICU patients. This suggests that hepatic dysfunction was not a prominent feature in this Cohort, unlike some earlier reports which

found elevated liver enzymes in severe cases, possibly due to direct viral injury or drug-induced hepatotoxicity [10,11].

When comparing hematological and LFT parameters based on gender, no statistically significant differences were observed. Although some studies have reported higher inflammatory and liver injury markers in males [12], the lack of significant variation in the current study could be due to the balanced clinical management and supportive care provided to all patients.

Overall, the study highlights that hematological parameters, particularly NLR and TLC, are more reliable indicators of disease severity compared to biochemical liver parameters. These readily available markers can be used in early risk stratification and monitoring of COVID-19 patients.

This retrospective study highlights the importance of hematological parameters, especially the Neutrophil-to-Lymphocyte Ratio (NLR), Total Leukocyte Count (TLC), and lymphocyte percentage, as reliable indicators of disease severity in COVID-19 patients. Patients requiring ICU care demonstrated significantly altered hematological profiles, indicating their potential utility in early risk assessment and clinical decision-making. Conversely, liver function test (LFT) parameters showed no significant association with disease severity in this Cohort, suggesting that hepatic involvement may not be a consistent feature in all COVID-19 patients. The findings support the use of simple, cost-effective hematological tests in the triage and management of COVID-19 cases, especially in resource-limited settings. Future prospective studies with larger sample sizes and longer follow-up periods are recommended to validate these results and explore additional prognostic markers.

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