As we all know that, Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2)¹ is a strain of coronavirus that causes COVID-19, the respiratory illness responsible for the COVID-19 pandemic.² COVID-19 is an infectious disease discovered in December 2019 in wuhan city, Hubei province, China^3,4. WHO announced disease outbreak on January 5^th 2020. It has spread worldwide over 110 countries affecting over 118,000 cases in a short period of less than 4 months raising a global concern. Hence, World Health Organization (WHO) declared COVID-19 a pandemic on 11th March, 2020. A beta corona virus has been identified as the cause for the illness which is mimicking the viral infection causing SARS and middle east respiratory syndrome.⁵ On 7^th January 2020 it was named as novel corona virus. SARS COV- 2 Pneumonia caused by corona virus (COID-19) with an incubation period of 2 to 14 days. Established modes of transmission of COVID-19 includes contact, fomites and respiratory droplets.⁶ SARS COV- 2 pneumonia resulted in significant mortality and morbidity worldwide and recorded millions of deaths.⁷

Among hospitalized patients with COVID-19 disease, it was noticed that most individuals who were severely affected found to be elderly population or individuals with pre-existing health issues or comorbidities during the initial days of disease. Mostly hypertension stood as the prevalent comorbidity followed by diabetes. Comorbidities that increase the risk of death among the COVID-19 cases were cardio vascular diseases, diabetes mellitus, chronic respiratory diseases, systemic hypertension and carcinomas. Estimated over all case fatality rate of COVID-19 globally was 2 to 4%. But in later days of pandemic, there were reports stating that even younger population were also severely affected and died due to covid 19. There were many factors associated for death in hospitalized covid 19 patients⁷.

And also the laboratory hematological and inflammatory biochemical markers may help to predict COVID-19 prognosis⁸. Many studies were pinpointed various prognostic markers, including D-dimer, C-reactive protein (CRP), lactate dehydrogenase (LDH), and high-sensitivity cardiac troponin, in serum of COVID-19 patients with poor outcomes ^{9, 10, 11, 12}. Deep analysis of abnormal levels of such factors and the interface between their functions in body organs and mechanisms of viral infection can provide the basis for first-line diagnosis as an efficient screening tool to predict the severity of the disease ¹⁰. Thus our study was planned to evaluate the hematological and inflammatory biochemical parameters to rule out the severity of the SARS Covid-19 among the affected patients in our set up.

The setting of the study was at Department of General Medicine, Mahatma Gandhi Medical College and Research Institute, Pondicherry. A six months observational study was conducted during the period from January, 2021 to June, 2021. All the cases of clinically diagnosed and as per the the standard case definitions admitted in the ward during the above period up to reach the required sample size were included (enrolled) in the study after duly following the inclusion and exclusion criteria as indicated below by reviewing the electronic records available in the department. Inclusion criteria: 1. Symptoms and Signs suggestive of SARS-Cov-2 and confirmed by Abdominal Ultrasound report 2. Patients who were given consent and have a permanent address in Pondicherry. Exclusion criteria: 1. Patients who did not give consent and not staying in Pondicherry. Objectives:1.To know the socio-demographic profiles of the study subjects 2. To compare and study the hematological, inflammatory biochemical parameters along with CT scores in patients with severe SARS-COV-2 pneumonia who succumbed to underlying illness with survived patients.

After receiving the Ethical committee clearance from the institution, the study began and the required data was collected by a pre-tested proforma pertaining to their socio-demographic profiles, various haematological & inflammatory biochemical parameters like CBP, LFT, RFT, Serum electrolytes, Serum albumin RBS & HbA1C, D-dimer and CT- Severity score etc; from the available electronic records. By means of convinient sampling method, a total of 240 patients who got admitted in our department from SARS Covid-19 during pandemic period were selected as sample size and among them about 120 patients who succembed to SARS Covid-19 were set as Non survivors group and remaining 120 patients who got survived and discharged were set as Survivors group by duly following the matching criteria. 

Finally, the collected data was compared and analyzed by using appropriate statistical tools like percentages, proportions, measures of central tendency, measures of dispersion, standard error of the mean and tests of significance etc; with the help of SPSS version 21 computer software. The study results were compared and discussed in the light of published material of various similar studies belonging to different authors and there by conclusions and recommendations were framed.

Table 1: Age & Sex wise distribution of both the groups of study subjects

                                   Mean  ± 2 SD = 58.25 ± 27.64 = 30.61 - 85.89,  P < 0.05

It was observed that, majority (74%) of the study subjects were belong to 50 years and above age group with the mean age 58.25 years and males(64%) were more when compared to females (36%) in this study. And also it was noticed that the ratio of male & female was same among  both the non survivors and survivors groups.

Figure 1: Age & Sex wise distribution of both the groups of study subjects

Table 2: Distribution of NLR (Neutrophil-Lymphocyte Ratio) among study subjects

• Significantly (P<0.05) about 52.5% of study subjects of Non survivors group fall under severe ARDS when compared to survivors group (15.3%) basing on the NLR report.

Table 3: Distribution of PF ratio among both the groups of study subjects

• Also it was observed that, significantly (P>0.05) about 70.8%% of study subjects of Non survivors group fall under severe ARDS when compared to survivors group (12.1%) basing on the PF ratio.

Table 4: Distribution of Hematological and Inflammatory Biochemical markers among study subjects

• Furthur with reference to Hematological and Biochemical inflammatory parameters significant results of differences were observed among Total count, Platelet count, Ferritin, LDH, D-dimer, Serum creatinine, Liver function tests of ALP,ALT & AST and Serum electrolytes (sodium & potassium) etc; between both the groups of Non survivors and Survivors

Figure 2: Distribution of Total count and Platelet count among both the groups

In the present study out of the total of 240 study subjects of both groups, Majority 74% were belong to 50 years and above age group with the mean age 58.25 years which was correlated with the findings of other studies like Zhou F and Yu T et al13 in 191 COVID-19 patients in Wuhan , Alizad G et al 14 and Samadizadeh et al 15etc. And males (64%) were more when compared to females (36%) in this study. It was understood that in our study the distribution of Covid-19 was more among the advanced age group and males as was observed in the above studies also. Globally, among hospitalized patients with COVID-19 disease, it was noticed that, majority of the individuals who severely affected were found to be elderly population or individuals with pre-existing health issues or comorbidities during the initial days of disease5. Significantly about 52.5% of study subjects of Non survivors group fall under severe ARDS when compared to survivors group (15.3%) basing on the NLR report. And also significantly (P>0.05) about 70.8%% of study subjects of Non survivors group fall under severe ARDS when compared to survivors group (12.1%) basing on the PF ratio. Related to this, high NLR was also observed by other studies like Alizad G et al14, Mitra A et al16, Huang C et al17, Huang Y et al18, Huyut M et al19, Yu H et al20, Li Q et al4 , Liu Y et al21 and Xianjun Wu et al22 etc; And regarding hypoalbuminemia, our study report was not significant between both the groups but the Study done by Ramadori G et al23 repoted significant hypoalbuminemia. Hypoalbuminemia was also found to be one of the consistent biochemical finding in COVID -19 patients.23 The main mechanisms act in reducing albumin serum concentration in patients with severe COVID-19-infection are reduction in albumin synthesis due to decreased food intake by patient or due to inhibition of specific mRNA- synthesis in the hepatocellular nuclei caused by the direct interaction of hepatocyte with the acute-phase cytokines. Higher levels of albumin at the time of admission in laboratory confirmed COVID-19 cases were showed better prognosis.24

Related to D-dimer value our study has reported significant elevated values among Non survivors group which was on par with the studies of Mitra C et al16, Huan C et al17, Huang Y et al18 and Lippi G et al25 respectively. And regarding LDH our study reported significant higher values which was on par with the reports of Alizad G et al14, Mitra A et al16, Huang C et al17 and Huang Y et al18 studies. And also with reference to high Leucocyte count, decreased Platelet count, elevated serum creatinine and blood urea our study observed significant result which was correlated with figures of the studies by Alizad G et al14, Tang N et al26 and Len P et al27 etc; where as Huyut M et al19, Yu H et al20 and Li Q et al4 were observed decreased Platelet count in their studies

Further related to Serum Ferritin, our study obsereved statistically significant defference between both the groups which was in close association with the findings of Wu C etal 28and Yasari F et al29 studies. In addition to this significant rise of liver enzymes were observed in our study which was similar to the findings reported by Kumar MP et al30 study and Bowe B et al31 study and with regard to serum electrolytes , this study observed significant  decreased sodium levels (hyponatremia) which was also observed by Martha J.W et al32 in his study and hypokalemia which corresponds to the finding by Gaetano A et al study33. Thus there were significant abnormalities of hematological, inflammatory biochemical and radiological abnormalities observed between both the groups of Non survivors and Survivors pointing towards prognosis of the disease SARS-Cov-2 in our set up.

LIMITATIONS

The study was a hospital-based and conducted in a small group of patients.

As the distribution, severity & mortality of the disease was observed more among the male and older age group population, it is very important to target our intervention and preventive strategies like vaccination, improving immunity by adaquate balanced diet and creating awareness pertaining to spread of the disease etc;among these groups to control the incidence and improve the survivability from SARS Covid-19. Also findings in the present study suggest WBC, NLR, PLT, D-dimer,LDH,Ferritin, LFT&RFT including BUN, Sodium & Potassium levels etc;Covid hematological & Inflammatory biochemical markers along with assessing the comorbid conditions as early as possible will help us to predict the severity and facilitate to enable early clinical intervention for patients, thereby reducing the mortality rate of COVID-19 patients and hopefully helping to control and prevent future epidemics and pandemics.

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