Laboratory Characteristics on SARS-CoV-2 Infection among Patients with Diabetes Mellitus: A Single-Center Retrospective Study

Background Diabetic patients have been severely affected by COVID-19 infection. It has been reported that the disease is more progressive leading to venous and arterial thromboembolism, due to multiple factors. This study was conducted to determine the hematologic parameters including D-dimer in diabetic patients with COVID-19 infection in association with disease severity and treatment. Method This retrospective cohort study was conducted at King Fahad Medical City, Saudi Arabia, after obtaining IRB approval, by collecting data regarding all laboratory parameters, disease severity, and anticoagulant treatment of COVID-19 diabetic patients (n = 159) from medical records from March to December 2020. Result Mean value of white blood cells, neutrophils, monocytes, eosinophils, lymphocyte monocyte ratio, C-reactive protein, serum ferritin, and LDH levels was elevated in severe cases than in mild cases with statistical significant increase in HbA1c (0.047), serum fibrinogen (0.007), C-reactive protein (0.005), serum ferritin (0.034), and serum LDH (0.015). Mortality was observed in 14 (8.8%) patients mostly with severe COVID-19 with diabetes. In our study, treatment with low molecular weight heparin was not significantly related to severity. A logistic regression analysis indicated an association of some laboratory parameters with severity and mortality of the disease. Conclusion The routine blood parameters if detected early will enable physicians to identify severe cases of COVID-19 patients with Diabetes for prompt treatment and save considerable time and resources.


Introduction
The COVID-19 has already infected more than 643 million people and resulted in more than 6.62 million deaths globally [1]. The average of country-/territory-specific COVID-19 CFR is about 2%-3% worldwide [2]. COVID-19 has varied clinical manifestations from trivial flu-like symptoms to multiple system failure and death, especially due to significant impact on the hematopoietic system and hemostasis.
It has been reported that prevalence of diabetes was 20% among COVID-19 patients [3]. Disease severity and outcome in these patients are related to numerous markers like serum ferritin, C-reactive protein, interleukin-6, fibrinogen, serum LDH, and D-dimer. Hematological aberrations in COVID-19 are associated with disease progression, severity, and mortality. Lymphopenia, thrombocytopenia, and abnormal coagulation profile is very well reported in patients of COVID-19 [4][5][6][7]. In patients with COVID-19 infection, the disease is more severe leading to venous and arterial thromboembolism, due to multiple factors such as inflammation, hypoxia, immobilization, diabetes, and disseminated intravascular coagulation, and is associated with increased morbidity [8]. Li et al. reported that the mortality rate for diabetic patients with COVID-19 was 14.5% which is higher than nondiabetic patients (5.7%). This could be due to a higher level of D-dimer and low lymphocyte count at admittance. So, patients with COVID-19 and diabetes need extra attention [9]. Every patient with COVID-19 is required to be placed on prophylactic doses of anticoagulation, usually with low molecular weight heparin (LMWH), unless contraindicated [10,11]. Kurt et al. reported that the leucocyte count, neutrophil count, neutrophil-to-lymphocyte ratio (NLR), platelet-tolymphocyte ratio (PLR), and ferritin level were significantly higher in the severe disease subgroup than in the nonsevere subgroup (p < 0:001). The lymphocyte counts and lymphocyte-to-monocyte ratio (LMR) were significantly lower in the severe disease subgroup than in the nonsevere subgroup (p < 0:001). NLR was positively correlated with the COVID-19 risk (adjusted OR 1.438, p = 0:012) whereas the association of PLR and LMR with COVID-19 risk was unclear [12]. However, there are very few studies on specific information regarding hematological parameters of patients with diabetes and COVID-19.
These parameters if detected early can play a vital role in the early prediction of disease severity and can provide a better guide for prompt management of patients, thus helping in decreasing the disease morbidity and mortality. All laboratory data were collected at admission such as HbA1c, hemoglobin, total WBC count, differential count, platelets, neutrophil-to-lymphocyte ratio (NLR), lymphocyteto-monocyte ratio (LMR), platelet-to-lymphocyte ratio   Patients were classified at the time of admission into mild and severe cases based on hospital guidelines at KFMC (Figure 1, flowchart).
Mild disease of COVID-19 was demarcated for patients with symptoms of fever, sore throat, cough, and no sign of pneumonia on X-rays. Patients with respiratory distress (respiratory rate > 30 breath per min, O 2 saturation less than 93%, and more than 50% lung infiltrate) were classified as having severe disease [13].
2.6. Data Entry and Analysis. Data was transferred to excel and analyzed in SPSS version 22, Illinois, USA. Descriptive statis-tics were calculated for hematologic parameters and Pearson correlation to correlate these parameters with the severity of the disease. Laboratory parameters were compared between mild and severe cases using independent t tests. Quantitative variables such as hemoglobin, white blood count (WBC), and differential white blood count including neutrophil-tolymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), prothrombin time PT, activated partial thromboplastin time (APTT), ferritin, Ddimer, lactate dehydrogenase (LDH), and C-reactive protein (CRP) were analyzed. p value equal or less than 0.05 was considered significant. Multinomial logistic regression was conducted to know the impact of the lab parameters mentioned above on COVID-19 severity and mortality.

Results
209 patients were identified according to our inclusion and exclusion criteria. Patients with missing data or hematological disease were excluded (n = 51) ( Figure 1). Demographic  Out of 158 patients, 94.3% of patients were more than 40 years, and COVID-19 with diabetes was predominant in males (91 (57.2%)) than females (68 (42.8%)). Severe cases were 107 (67.3%) and mild cases were 51 (32.1%). All demographic data were nonsignificant between mild and severe groups except for hospital stay which was significantly longer in severe cases ( Table 1).
Mortality was observed in 14 (8.8%) patients, and all of these had severe COVID-19 with diabetes. LMWH was started in 92.5 (%) of all cases.

Discussion
Variations in hematological characteristics in patients with COVID-19 are evolving as imperative features of COVID-19 infection trigger coagulation activation, inflammatory reactions, hypercoagulability induction, and cytokine storms that ultimately indicate disease severity. The patient deterioration condition will lead to admission to the intensive care unit and death [14].
An analysis by Varikasuvu et al. showed that diabetic COVID-19 patients are highly vulnerable to coagulation abnormalities and inflammation than the nondiabetic COVID-19 cases. The levels of serum ferritin (standardized mean difference (SMD): 0.47), C-reactive protein (SMD = 0:53), interleukin-6 (SMD = 0:3), fibrinogen (SMD = 0:31), and D-dimers (SMD = 0:54) were increased in diabetic COVID-19 cases compared to nondiabetic COVID-19 patients, signifying coagulation irregularities and inflammatory storm [15]. Li conducted a study for 199 COVID-19 patients, 76 were diabetic and 123 were nondiabetic, and reported that the mortality rate of  Journal of Diabetes Research COVID-19 patients with diabetes was significantly higher than those without diabetes. Diabetes, higher level of D-dimer, and lymphocyte count less than 0:6 × 10 9 /L at admission were the risk factors associated with in-hospital death. Thus, diabetic patients are more prone to develop severe COVID-19 infection and higher mortality rate due to their hypercoagulable proinflammatory stage [9,16]. In a retrospective cohort study of 380 patients, the numbers of lymphocytes and eosinophils were considerably lower in patients with critical disease than in those with      Journal of Diabetes Research severe or moderate disease (p < 0:0001), and prothrombin time, D-dimer, and fibrin degradation products considerably increased in severe cases (p < 0:0001). Thrombotic and hemorrhagic events played a major role in patient's death (19 [35%] of 55) [17]. Bansal et al. showed the significant association of D-dimers with the severity of the COVID-19 disease. Patients with acute lung injury and severe infection will have disseminated intravascular coagulation (DIC) secondary to sepsis [18]. Ayusha et al. reported that 1.5 μg/mL is the optimal cutoff value of admission D-dimer for predicting mortality in COVID-19 patients, with good sensitivity and specificity suggesting that laboratory interpreters of clinical decline can aid in intensifying the care of the patients with this infection and support in suitable triaging and resource deployment [19]. In our study, it was more than 2.5 mg/L in both mild and severe cases.
A local study also reported that diabetic COVID-19 patients have a higher mortality rate than their nondiabetic counterparts, and patients with uncontrolled diabetes (HbA1C > 7%) on admittance often end up in intensive care [20]. In our study, mortality was observed in 14 (8.8%) patients, and all of these had severe COVID-19 with diabetes.
In our study, LMWH was started in 92.5% of all cases. Terpos et al. in a Chinese study reported that LMWH administration among patients with markedly elevated D-dimers or in those meeting the criteria for sepsis-induced DIC was significantly associated with improved 28-day overall survival, p = 0:017 and p = 0:029 among two patient groups, users versus nonusers, respectively [21].
The anti-inflammatory properties of LMWH may be beneficial in COVID-19 patients and should be integrated with other antithrombotic treatments such as antithrombin, and recombinant thrombomodulin to hinder the complex "immunothrombosis" process [10]. In our study, treatment with low molecular weight heparin was not significantly related to severity.
The association between laboratory parameters and severity of disease has been reported by other studies. Taj et al. in their study concluded that leukocytosis, neutrophilia, elevated neutrophil-to-lymphocyte ratio, APTT, Ddimer, LDH, serum ferritin, and CRP are associated with severity of COVID-19 disease. These laboratory biomarkers therefore play a vital role in the early prediction of the disease [7].
Many infections can be detected using the total blood count test, which can easily be available and cheap but at the same time very informative. Hematological, inflammatory, and other markers can be used to evaluate the severity and prognosis of COVID-19 diseases as there is predictive relevance because all SARS-CoV-2 genetic variants have a significant potential for thrombosis, especially in diabetic patients [22].
The addition of these parameters in the regimens for patients' categorization on admission will facilitate prompt effective intervention and proper decision making in the course of clinical case management [23].

Conclusion
In conclusion, COVID-19 disease affects the hematopoietic system in COVID-19 patients with diabetes leading to major complications and untimely death. This study determines laboratory parameters including D-dimer at admission in diabetic patients with COVID-19 infection in association with disease severity and mortality.
Further, optimal anticoagulation regimen with or without adjunct antithrombotic therapies such as LMWH may be useful in patients with COVID-19.

Limitations.
Our study has certain limitations. Some patients were excluded because of incomplete documentation of laboratory testing. Our study design is retrospective; hence, findings are limited to the accuracy of record keeping. Furthermore, duration of DM was not recorded which may affect the findings. The results should be interpreted with the caution that diabetes may coexist with other conditions such as cardiac diseases in COVID-19 patients. Therefore, further well-controlled studies are needed in the future to establish an independent role of diabetes in COVID-19.
These limitations do not undervalue the findings of the present study which are robust and add value to the limited literature on COVID-19 patients within the Arab region. Further, lack of a control group is another limitation. We suggest multicenter studies to clarify the role of lab parameters in the severity of disease and mortality in COVID-19.

Data Availability
Our institution restricts access to data due to patient confidentiality, ethical concern, and institution ownership.

Conflicts of Interest
The authors report no conflict of interest.