A Biochemical Analysis of Patients with COVID-19 Infection

Several studies have demonstrated that age, comorbidities, and abnormalities in different clinical biomarkers can be important to understand disease severity. Although clinical features of COVID-19 have been widely described, the assessment of alterations of the most common biochemical markers that are reported in patients with COVID-19 still has not been well established. Here, we report clinical and blood biochemical indicators of 100 patients with COVID-19. Throat-swab upper respiratory samples were obtained from patients and real-time PCR was used to confirm SARS-CoV-2 infection. Gender, age, and clinical features such as diabetes mellitus, hypertension, and smoking habits were investigated. Biochemical parameters were categorized and analyzed according to these clinical characteristics. Triglycerides, GPT, and ALP are the biochemical markers that changed the most in the group of hypertension patients. Cholesterol and triglycerides were significantly different (P=0.01; P=0.04, respectively) between diabetic and nondiabetic patients with COVID-19. Potassium levels were significantly different (P=0.03) when comparing smokers with nonsmoker patients. Our results suggest several potential biochemical indexes that changed in patients with COVID-19 and whether certain comorbidity and clinical characteristics influence these markers.


Introduction
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the recently discovered severe acute respiratory syndrome coronavirus 2, which is still spreading throughout the world. Most infected patients with COVID-19 will have mild to moderate respiratory illness that will be recovered without special medical care. However, elderly people and those with chronic medical conditions such as respiratory disease, heart disease, diabetes, and cancer are more likely to develop severe illnesses [1][2][3]. According to recent World Health Organization (WHO) figures, more than 110 million cases have been confirmed worldwide, with 2.44 million deaths as of February 16, 2021 [4].
Iraq has been greatly impacted by the ongoing outbreak of COVID- 19. e first COVID-19 patient was reported in Iraq on 24 February 2020 [5]. Currently, as of February 16, 2021, over 650,000 diagnosed cases have been reported with more than 13,000 deaths [4]. Several biochemical tests are dramatically changed in patients with COVID-19. Early studies of COVID-19 showed substantial levels of alanine aminotransferase (ALT) in intensive care unit patients [6]. In addition, D-dimer, creatinine, blood urea, and neutrophil levels were also substantially increased in patients with severe symptoms, while lymphocyte counts were reduced [7]. D-dimer levels were also elevated in 70% of patients with severe symptoms and deceased cases [8].
Deng et al. found that, in certain patients, ALT and aspartate transaminase (AST) showed higher levels than the normal range with decreased total bilirubin levels. Creatinine and creatine phosphokinase were both increased in 13% of patients with COVID-19 [9] while Wu et al. observed a change in the percentages of liver function biomarkers (ALB, GGT, AST, ALT, TBIL, and ALP) [10].
is study aimed to demonstrate a systematic assessment for some of the biochemical laboratory tests in patients with COVID-19. All patients were admitted to the Al-Hussein Teaching Hospital, i-Qar Province, Iraq. Real-time PCR was used to confirm SARS-CoV-2 infection. Clinical characteristics and blood biochemical tests of COVID-19 patients were examined and recorded. All patients were referred to Al-Hussein Teaching Hospital in i-Qar Province, Iraq, between  November 2 and December 30, 2020, showing COVID-19 symptoms. roat-swab upper respiratory specimens were obtained from 100 patients and real-time PCR (polymerase chain reaction) was used to confirm SARS-CoV-2 infection. Clinical characteristics and blood biochemical tests of COVID-19 patients were examined and recorded. Gender, age, and clinical characteristics such as diabetes mellitus, hypertension, and smoking have been investigated. Informed consent was obtained from patients. e study has been approved by the Institutional Review Board.

Sample Collection and Data
Processing. Venous blood (4.5 mL) was obtained. Blood samples were dispensed into a gel tube. All tubes were allowed to stand for 30 minutes at room temperature, followed by centrifugation for 10 minutes at 3500 rpm to get the serum. Liver and kidney function tests including alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin, creatinine, and blood urea were measured. Uric acid, triglyceride, total cholesterol, high-density lipoprotein (HDL), calcium (Ca +2 ), sodium (Na + ), potassium (K + ), chloride (Cl − ), magnesium (Mg +2 ), and phosphorus (P) were also measured using Gesan Chem-200 platform (Gesan Production SRL, Italy) according to the manufacturing protocols.

Statistical Analysis.
Biochemical parameters were analyzed and categorized according to the following variables: (a) diabetes mellitus, (b) blood pressure, (c) smoking, and (d) gender. Biochemical tests were compared across patients grouped in these categories. Significance testing was performed in GraphPad Software using a t-test. A P value of <0.05 indicated statistical significance.

Results
A total of 100 COVID-19 patients were admitted to Al-Hussein Teaching Hospital in i-Qar Province, Iraq, from 2 November to 30 December 2020. Most cases (52%) were between the ages of 21 and 40 years, followed by those aged 41-60 years (29%). Approximately 54% of patients were female and 46% were male (Table 1). Most cases experienced influenza-like symptoms such as fever, cough, and mild myalgia during their time at the hospital. All patients were discharged following recovery of clinical symptoms. Diabetes mellitus, present in 23 out of 100 patients, was the most common comorbidity, followed by blood pressure, present in 14 patients. In addition, a summary of biochemical indexes outcomes among patients with COVID-19 is presented in Table 2.
In the blood pressure group, triglycerides, alanine aminotransferase (GPT), and alkaline phosphatase (ALP) were the most common biochemical laboratory abnormalities identified ( Figure 1). However, no significant association was found between elevated blood pressure and normal blood pressure in all biochemical laboratory parameters as shown in Figure 1. We then analyzed the correlation between the biochemical characteristics and diabetes mellitus in patients with COVID-19. Among the biochemical parameters, cholesterol and triglycerides had a significant difference (t � 2.572, P � 0.01; t � 1.992, P � 0.04, respectively) between the diabetic and nondiabetic COVID-19-infected patients ( Figure 2). Furthermore, in a few patients, creatinine, alanine aminotransferase (GPT), alkaline phosphatase (ALP), and aspartate aminotransferase (GOT) levels were shown to be higher than the normal range. However, when comparing them according to diabetic and nondiabetic classification, none of these variations were statistically significant ( Figure 2). Figure 3 indicates the gender-based breakdown of biochemical indexes. Out of 100 patients, 54% of the patients were female and 46% were male. Some biochemical measures such as creatinine, triglycerides, alkaline phosphatase and GOT, were found to have increased levels ( Figure 3). However, when comparing these biomarkers between males and females, no evidence of significant differences was found.
Smoking has been shown to increase serum lipid profiles including triglycerides [11,12]. We, therefore, analyze whether smoking habits may influence the balance of serum biochemistry in patients with COVID-19. Low serum concentrations of magnesium, phosphorus, and calcium, have been seen in certain patients ( Figure 4). Further analysis revealed high serum levels of creatinine, GPT, ALP, GOT, and urea in just a few other patients ( Figure 4) whereas only potassium concentrations were significantly different (t � 2.140, P � 0.03) when comparing smokers with nonsmoker patients.

Discussion
COVID-19 is an ongoing pandemic and the virus is still spreading worldwide. As stated by World Health Organization (WHO) reports, more than 110 million cases have been confirmed globally and 2.44 million deaths through February 16, 2021 [4]. On 24 February 2020, the first COVID-19 patient was confirmed in Iraq [5]. Recently, as of February 16, 2021, over 650,000 diagnosed cases have been reported with over 13,000 deaths [4]. Several studies have shown that age, comorbidities, and abnormalities of various clinical biomarkers can be essential to understand disease severity [13][14][15][16]. Even though clinical features of COVID-19 have been widely described, the overview of changes in the most common biochemical parameters that are observed in patients with COVID-19 infection is still unclear. erefore, this report aims to study the changes in certain biochemical markers encountered in patients with COVID-19. In addition, clinical characteristics and comorbidity in 100 patients with COVID-19 have also been studied.
A strong relationship between lipid profiles and hypertension has been reported in [17][18][19][20]. Higher triglycerides values were found in patients with elevated blood pressure which are consistent with these reports. We found           that triglycerides, GPT, and GOT were elevated although there was no significant difference between COVID-19 patients with elevated and normal blood pressure suggesting that COVID-19 infection may alter these biochemical laboratory markers regardless of hypertension. Furthermore, the higher triglyceride levels in certain patients might be due to body fat and distribution, a condition not investigated in this study. ese findings seem to be consistent with other studies which found that high levels of triglyceride were more positively correlated with body fat than with changes in blood pressure [21,22]. We discovered a marked increase in levels of cholesterol and triglycerides in diabetic and nondiabetic COVID-19-infected patients. Creatinine, GPT, ALP, and GOT values were shown to be higher than the normal range in some COVID-19infected patients.
e most notable comorbidities with COVID-19 in our study were diabetes (23%) and hypertension (14%). Coronaviruses bind to their target cells via angiotensinconverting enzyme 2 (ACE2), which is widely expressed in the kidney, intestine, and epithelial cells of the lung [23]. It has also been demonstrated that the expression of ACE2 is markedly upregulated in patients with diabetes which would promote the infection with COVID-19 [24,25].
Several epidemiological data have shown no substantial correlation between smoking and disease severity in patients with COVID-19 [26][27][28]. In contrast, Leung et al. reported that smokers showed an upregulation of ACE2 gene expression than nonsmokers which facilitated COVID-19 infection [29]. When we analyzed the data according to smoking habits, elevated serum levels of triglyceride, creatinine, GPT, ALP, GOT, and urea were shown in few patients. Besides that, the concentrations of magnesium, phosphorus, and calcium were decreased in other patients. Interestingly, potassium levels showed significant differences when comparing smokers with nonsmoker patients. It has been shown that smoking habits might have induced alterations in potassium levels [30,31]. However, the link between smoking and potassium levels has not been well studied. In conclusion, our results suggest several potential biochemical indexes change in patients with COVID-19 and that certain patient and clinical characteristics may influence these indexes.

Data Availability
All data are included in the supplementary materials. Disclosure e manuscript has been deposited as a preprint in Heliyon [32].

Conflicts of Interest
e authors declare no conflicts of interest.