In the current study, 2478 patients with covid-19 referred to the emergency department of Shahid Mohammadi Hospital in Bandar Abbas in 2019 were examined. These patients' most common clinical symptoms were shortness of breath, followed by cough and fever. Considering the transmission of the SARS-CoV-2 virus, mainly through respiratory droplets, respiratory symptoms are more common than other symptoms in these patients. Although, different immune statuses, comorbidities, ways of virus transmission, and environmental conditions in different studies can also explain the different findings. In the current study, the most common underlying disease in the examined covid-19 patients was hypertension, followed by diabetes and ischemic heart disease. The present study identified old age, shortness of breath, hypertension, ischemic heart disease, dyslipidemia, stroke, malignancy, CRP 3 + and high ESR as the main predictors of mortality in covid-19 patients. On the other hand, receiving Macrolide and the presence of anorexia had a protective role against mortality in these patients.
The biomarkers of COVID-19 patients who survived compared to those who did not were significantly different at admission, according to a pooled study of 10 studies involving 1584 patients(22). in line with the present study, in the study of Qapanuri et al. increase in CRP was a predictor of death in patients with Covid-19 (23). Troponin, D-dimer, CRP, and WBCs levels were significantly higher in COVID-19 patients who died than in COVID-19 survivors. High troponin and WBC levels were considerably associated with families that lost more than one member compared to the unrelated COVID-19 patient control(24). In the present study, although there was no correlation between positive troponin and mortality in the multiple analysis, the mortality rate in patients with positive troponin was significantly higher than in patients with negative troponin. Enver Yüksel's study showed that The in-hospital mortality rate was considerably higher when the creatinine was most significant (25). Also, in the present study, the average creatinine was significantly higher in deceased patients. In terms of the relationship between the number of decreased platelet count and mortality, the findings of our and Homayouniyeh et al. studies are consistent. In the present study, the average number of platelets was significantly lower in the deceased patients compared to the surviving patients. There was also a significant relationship between the number of platelets and mortality in either univariate or multivariate analyses. Also, in YeşimIşler et al., In patients with COVID-19 pneumonia, platelet count, mean platelet volume, and mean platelet volume to platelet ratio may be related to mortality. (26, 27).
In most studies, in line with our findings, the same diseases, especially hypertension and diabetes, were among the most common underlying diseases in Covid-19 patients (23, 26, 28–32). In the cohort study of Mirjalili et al., cardiovascular disease, diabetes, chronic neurological disease, chronic lung disease, and malignancy increased the chance of death. Also, patients hospitalized in the ICU had a higher risk of death, and the mortality was higher in the old age group and those with underlying diseases (32). like our study, in Gozidehkar et al., age was recognized as a risk factor for death due to covid (28). Also, in most other studies like Moon et al.’s study, The highest number of deaths is related to the age groups of 66 to 70 years (29, 33). Moon et al.’s study also emphasize fever and body temperature as risk factors. However, in the case of fever, no significant relationship with mortality was seen in our study and Andriani et al.’s study (29, 34). Compared to the study of Mirjalili et al., one of the risk factors that was not investigated in the current study is the severity of Covid-19. In most of the previous studies, ICU hospitalization is also considered a measure of the severity of the disease. In terms of other predictors of mortality, the Mirjalili et al. study's results are almost consistent with this study. Also, in Tian et al.’s review study, the presence of underlying diseases such as hypertension, coronary artery disease, and diabetes had a significant relationship with mortality (35).Appleman et al. research shows that individuals with a history of CKD have significantly higher mortality and readmission rate. They also show a higher 12-week death and readmission rate of SARS-CoV-2 infected patients in nearly all CKD groups. In contrast, prior research mainly highlighted increased mortality among dialysis and KTx patients (36). In the study of Qapanuri, the frequency of chronic kidney failure, was significantly different between the deceased and survived groups (23). However, in multiple analysis, chronic renal failure was not identified as risk factors for covid-19 mortality in our study.
The mortality rate is reported to be 2.8% in men and 1.7% in women. Mortality in healthy people is 0.9% (36). The results of Albitar et al.’s and Zhang et al.’s study were consistent with the present study in terms of most of the predictors of mortality (37, 38), except for gender. In Albitar et al.’s study, the male gender was identified as a risk factor for death. However, there was no relationship between gender and death in the present study. Gender distribution in the patients investigated in these studies, the different severity of the disease in the patients of Zhang et al.’s study (the presence of mild disease in only three patients), the number of comorbidities and many other factors, including the time of the hospital visits, method of Covid-19 diagnosis. etc., are among the factors contributing to the discrepancy between studies regarding the association of gender with mortality.
In Du et al.’s study, age greater than or equal to 65 years, underlying cardiovascular or cerebrovascular disease, CD3 + and CD8 + T cell count less than or equal to 75 per microliter, and cardiac troponin I greater than or equal to 0.05 ng/ml, were associated with a significant increase in the risk of death due to Covid-19 pneumonia (34). In most terms, their outcomes are the same as ours. However, the numbers of these particular T cells were not measured in the present study, and probably the type of measured troponin, the sensitivity of the diagnostic test, and the cut point considered in Du et al.’s study are different from the current study. In addition, all patients in Du et al.’s study had covid-19 pneumonia, while in the present study, we had patients without lung involvement.
In the study of Homayouniyeh et al., among the clinical features, old age, low oxygen saturation, leukocytosis, low lymphocyte ratio, and decreased platelets were significantly associated with increased mortality. Also, a high RALE score in the initial radiograph, the presence of pleural effusion in the initial CT scan, the development of pleural effusion in the follow-up CT scan, and the deterioration of the involvement intensity score in the CT scan had a significant relationship with increased mortality (26). Another determinant of covid severity (i.e., low oxygen saturation) was proposed in this study. The severity of the disease was not assessed in our study, as mentioned above. However, the findings of this study with our study are consistent in terms of the relationship between old age and mortality.