December 2019, Chinese scientists first identified SARS-CoV-2 as the etiology of COVID-19 disease [13]. At first, COVID-19 was classified as a respiratory illness, with pneumonia to be the prevailing and most fatal consequence. However, SARS-CoV-2 had been revealed to elicit an exaggerated and unregulated immune responses, known as immune hemostasis, which leads to various complications including thrombosis, damage to tissues, DIC, ARDS, and MODS [14]; Therefore, it is imperative to comprehend COVID-19 not only as a respiratory illness but additionally as a possible multisystem disorder [15].
In this study, as regard comorbidities: significantly higher DM (67.8% vs. 36.4%; p < 0.001) and chronic chest disease (39.1% vs. 11.4%; p < 0.001) among severe group was found. Hypertension as recorded was (29.5%; 32.2%) in non-severe group and severe group respectively. CVS was (11.4%; 16.5%) in non-severe group and severe group correspondingly. CKD was (18.2%; 21.2%) in non-severe group and severe group respectively. In accordance, Abdelfattah et al. [16]reported that a strong association existed among the COVID-19 infection severity and the prevalence of co-morbidities, particularly systemic HTNand DM. Ji et al. [17]also observed similar findings, A countrywide retrospective case-control research was undertaken in Korea, involving 219,961 participants with COVID-19. The work found that co-morbidities, particularly DM and HTN, had a substantial impact on the COVID-19 infectionseverity. According to Khadija et al. [18], 32% of individuals with DM had HTN and 9.2% had underlying ischemic cardiac disease. Both of these conditions are known to be risk factors for negative outcomes among individuals with COVID infections.
In this study, it was found that lymphocytic count was significantly lower among patients with severe group. Also, severe groups exhibited significantly greater serum CRP levels and serum ferritin levels. While no statistically significant variation existed as regards levels of D-dimer among non-severe and severe groups of patients. This agrees with Abdelfattah et al.[16] reported that A strong connection was seen between serum ferritin and D-dimer and the COVID-19 infection severity. Furthermore, Elsharawy et al. [19] found a correlation between serum ferritin levels and both the severity of the illness and the ability to predict admission to the ICU. This was in opposition to the findings published by Yao et al. [20], The study discovered a significant association amonglevel of D-dimer and the severity of the illness. Furthermore, they observed that D-dimer level served as a dependable prognostic marker for predicting in-hospital mortality in individuals admitted for COVID-19. This was in contrast with what was reported by Yao et al.[20]found that D-dimer level correlates with disease severity and was a reliable prognostic marker for in-hospital mortality in subjects admitted for COVID-19.
In this study, it was found that frequency of need for MV was significantly higher among patients with severe disease (66.1% vs. 6.8%; p < 0.001) while venture mask was the method of correction of desaturation among non-severe group (93.2% vs. 35.7%; p < 0.001). In accordance, Abdelfattah al.[16]reported that, a positive correlation was found between severity of COVID-19 infection, days of hospital stay, the need for ICU admission, and mechanical ventilation which seems a logic finding.
Higher levels of serum CRP are associated with higher mortality in people with severe COVID-19 disease[20]. more specifically, CRP values above 77.35 mg/L [21]. Davoudi et al. [22] reported that, although the level of CRP was higher in non-survived patients, this difference was not statistically significant. This is the same as proved by Alroomi et al.[23]conducted a retrospective study on 595 COVID-19 subjects, where higher levels of serum ferritin were found to be an independent predictor of mortality.
Blood picture of patients with COVID-19 characterized by normal or low count of WBCs and decreased level of lymphocytes. Increased levels of WBCs and neutrophils were found in 68% and 72% of patients[24]. Petrilli et al.[25]reported striking findings regarding the predictive value of inflammatory markers to distinguish future critical from non-critical illness.
In this study, at cut off > 133 mg/dl, baseline serum CRP level had 65.7% overall accuracy in prediction of severe disease among the studied with area under curve was 0.673. Ahnachet al.[27]confirmed that the CRP was a robust predictor of adverse disease outcome. CRP was also an independent discriminator of severe/critical illness on admission in comparison with other biological factors. These results were in agreement with similar report of Luo et al. [28]found an AUC of CRP for discriminating disease severity on admission at 0.783. With a cut-off value of 41.3, CRP exhibited similar results of our study with sensitivity of 65%, specificity of 83.7%, PPV of 81.6%, and NPV of 68.2%.
In this study, it was found that predictors for severe disease among the studied patients were DM (odd's ratio = 3.45), chronic chest disease (odd's ratio = 2.22) and CRP (odd's ratio = 2.19). Similarly, Wang et al.[29] and Wu et al.[30] reported a significant association of the COVID-19 severity with diabetes.
In this study, it was found that predictors for mortality among the studied patients were age (odd's ratio = 1.78), DM (odd's ratio = 2.89), chronic chest disease (odd's ratio = 3.01), serum albumin (odd's ratio = 1.90), serum CRP levels (odd's ratio = 2.11) and d-dimer (odd's ratio = 2.98). This is consistent with the findings stated by Shi et al.[31]reported that, age ≥ 70 years was found to be an independent risk factor for in-hospital death for patients with diabetes as well as for patients without diabetes (hazard ratio (HR) 2.39 and 5.87, respectively).
In this study, at cut off> 150 mg/dl, baseline serum CRP level had 63% overall accuracy in prediction of mortality among the studied with area under curve was 0.674. meanwhile, baseline d-dimer had 67.7% overall accuracy in prediction of mortality among the studied with area under curve was 0.706. In a cohort conducted by Smilowitz et al.[33], including 2782 COVID-19 patients, CRP levels above 108mg/L we associated with disease severity (47,6% vs 25,9%) and a higher mortality (32,2% vs 17,8%) (277). Similarly, in a retrospective study conducted by Sadeghi et al.[33] including 429 patients, it has been shown that not only the severe cases had significantly higher CRP levels than non-severe patients, but also that patients with CRP > 64.75 mg/L were more likely to have severe complications.
Limitations of the work involved the relatively small sample size. The work had been conducted in a single center.