The current study investigated the factors affecting in-hospital mortality of patients with COVID-19 hospitalized in one of the main teaching hospital in central Iran. The results showed that the mean ± SD of age was 17.53 ± 56.29 years, and about 60% of inpatients were male. In line with our findings, in a study by Chen et al., the mean age of inpatients was reported as 55 years, of which 67% were male (10). In another study by Wu et al., the highest mortality rate was reported in older men with underlying disease (3). During a systematic review and a meta-analysis, Li et al. epidemiologically investigated clinical features, risk factors, and treatment outcomes in patients with COVID-19. The results showed that the mean age of all patients with COVID-19 was 46.7 years, of which 51.8% were male (11).
In the present study, 93 patients (16.23%) died in the hospital. The mean ± SD of age of these patients was 14.36 ± 69.71 years. However, the results showed that age, gender, marital status, place of residence, cigarette, hookah, and drug use, recent travel history, and the history of contact with the suspect person were not different between survivors and non-survivors. In a study conducted in China, Wei et al. showed that the mean age of individuals who died from COVID-19 was 51 years, and most of them were elderly men (12). In a study by Zhou et al., the mean age of individuals who died from COVID-19 was reported as 69 years, which was significantly higher than the survived group, and most of the deceased patients were male (2). In a study by Tang et al., this rate was obtained 64 years which was significantly higher than the discharged group (13).
The most common underlying diseases in patients with COVID-19 in the present study were hypertension (36.4%), DM (26.6%), and CHD (12.8%), respectively, all of which were observed in non-survivors. Chen et al. also reported that 51% of patients with a definitive diagnosis of COVID-19 had an underlying disease (10). Similarly, Liang et al. showed that 40% of patients with COVID-19 had an underlying disease, including cardiovascular, pulmonary, and cerebrovascular diseases, as well as DM and cancer, respectively (14). In another study performed by Zou et al., 51.59% of individuals had an underlying disease, including hypertension, cardiovascular diseases, DM, chronic respiratory disease, or cancer (15). In another study, the most common clinical manifestations of COVID-19 were reported as fever, cough, and fatigue (16). In Zhang et al.’s study, gastrointestinal symptoms, hypertension, and DM were reported as the main underlying diseases in these patients (17).
The present study showed that the most common clinical symptoms in patients were cough, fever, shortness of breath, and myalgia. Shortness of breath and loss of consciousness were significantly more common in non-survivors. Previous similar studies have shown that the most common symptoms observed in patients with COVID-19 were fever and chills, shortness of breath, cough, myalgia, weakness, lethargy, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea (6, 10, 15). Common symptoms in patients with COVID-19 were reported by Wei et al. as fever and cough (12). Zou et al. stated that the most common symptom present in patients included fever, cough, shortness of breath, hemoptysis, and diarrhea, respectively (15). In a meta-analysis, Cao et al. showed that the most prevalent clinical manifestations in patients with COVID-19 were fever, cough, shortness of breath, myalgia or fatigue, and respiratory distress (18).
The mean ± SD of PR and RR per minute in this study were significantly higher in non-survivors. On the other hand, the percentage of O2 saturation in non-survivors was lower. GCS of 15 was more common in survived patients. In a study by Liu et al., the means of heart rate and RR per minute were 24 and 94, respectively (19). A RR > 24 per minute was reported 29% in Chen et al.’s study, which was significantly higher in deceased patients (63% versus 16%). Also, a heart rate > 125 beats per minute was observed in only 1% of patients. Fever was recorded in 94% of patients and it was similar in survivors and non-survivors (10).
In the present study, the most findings of lung CT scan were bilateral infiltration (90.5%), peripheral lobes involvement (65.3%), GGO (45%), and air bronchogram (43%), generally. In non-survivors, mixed GGO/consolidation, air bronchogram, bilateral infiltration, mixed central-peripheral lobe involvement, LAP, crazy paving, and septal thickening were observed, but consolidation and peripheral lobe involvement were significantly higher in survivors. Chen et al. found that pulmonary involvement was mostly as bilateral pneumonia followed by GGO lesions (10). Francone et al. showed that the most common view observed on CT scan (less than 7 days from the onset of symptoms) was the GGO; and after 7 days, crazy paving, consolidation, and fibrosis were the most common views, respectively (20). In a study by Huang et al., 98% had bilateral lung involvement, and in general GGO was more common (6). Cao et al. mentioned the main findings of imaging as bilateral pneumonia and GGO (18). Salehi et al. stated that one of the known features of COVID-19 in patients’ early lung CT scans is GGO with peripheral or posterior distribution, mainly in the lower lobes and less in the middle lobe. Septal thickening, bronchiectasis, pleural thickening, and subpleural involvement are some of the less prevalent findings that are mainly seen in the later stages of the disease. Pleural effusions, pericardial effusions, lymphadenopathy, cavitation, halo symptoms, and pneumothorax are very rare but may be seen as the disease progresses. Imaging patterns related to clinical improvement usually occur after 2 weeks of illness and include the gradual removal of opacities and the decrease in the number of lesions and involved lobes (21).
In this study, the means ± SD of WBC, blood sugar, urea, LDH, aspartate transaminase (AST), serum potassium, phosphorus, and ESR were higher in non-survivors, but the mean ± SD of lymphocytes, serum potassium, calcium, and albumin were higher in survivors. In Huang et al.’s study, laboratory features in patients with COVID-19 included leukopenia (25%), lymphopenia (25%), and increased AST (37%) (6). Zhang et al. also found that prothrombin and D-dimer levels were higher in patients with ICU than (17). In a meta-analysis, Lippi et al. reported that in almost all patients with COVID-19 (99%), the troponin level increased to the maximum normal range. In addition, troponin levels highly increased in patients with severe infection than those with milder disease; and it could predict the likelihood of heart damage and disease progression toward worse clinical signs, and protective cardiac treatments may be helpful in these patients (23). In another systematic review and meta-analysis, it was reported that out of 4,663 patients, the most common laboratory finding related to COVID-19 was C-reactive protein (CRP), followed by decreased albumin, increased ESR, decreased eosinophil, increased interleukin 6, decreased lymphocyte count, and finally increased LDH, respectively. Their meta-analytic findings on 1905 patients also showed that the increased CRP and LDH levels, as well as decreased lymphocyte in the patients’ blood samples, would be significantly associated with increased disease severity and mortality (25).
Our findings demonstrated that the most treatments performed were Kaletra, hydroxychloroquine, and oseltamivir, respectively. In non-survivors, vitamin D3, antibiotics, tavanex, corticosteroids, non-invasive mechanical ventilation, invasive mechanical ventilation, and RRT were further used. However, hydroxychloroquine was more administered to survivors. Zhou et al. stated antibiotics and corticosteroids as the most commonly used treatments (2). Moreover, Chen et al. mentioned the most commonly used treatments for patients as antiviral drugs, oxygen therapy, and antibiotics, but found no evidence of their effectiveness (10). Various treatments have been suggested for patients over time, which the reason for the observed differences may be due to the increased knowledge and experience of physicians regarding drugs effectiveness in the treatment of COVID-19 and its complications.
The most common complications observed in our studied patients included respiratory failure, sepsis, and acidosis, respectively. All complications were more common in non-survivors. Zhou et al. mentioned sepsis, respiratory failure, ARDS, and heart failure as the most common complications, all of which were significantly higher in non-survivors. The results regarding the difference between the onset of symptoms and the onset of complications in our study were similar to the obtained results by Zhou et al.’s(2). In Chen et al.’s study, ARDS was observed in 17% of patients, which was the most common complication (10).
Hospital readmission was observed in 5.2% of patients in the present study, which was higher in non-survivors. ICU admission was observed in 20.5% of patients, which was higher in non-survivors. In Zhou et al.’s study, 26% of patients were admitted to the ICU, which was significantly higher in non-survivors (2). Also, in our study, the mean of hospital stay were higher in patients with in-hospital mortality, but it was lower in deceased patients in Zhou et al.’s study. However, similar to their results (2), the duration of ICU admission in patients of both groups was not significantly different in the present research. Also, in line with their results, the means of the time between the onset of clinical symptoms and outcome were more common in non-survivors (2).
The results of the present study showed that 76.7% of patients with ICU admission died, which was significantly higher than survivors. In the study by Auld et al., the mortality rate of patients with ICU admission was reported as 33.9%, which was lower than the result obtained in the present study. This rate was reported as 52–62% in other similar studies (28). Another study in the United States found that 50–67% of patients with ICU admission died (29).
The results of this study showed that plural effusion in lung CT scan, WBC, albumin, non-invasive mechanical ventilation, and ARDS were the predictive factors for in-hospital mortality in patients with COVID-19. Wang et al. found that CRP could be a valuable marker for predicting the likelihood of exacerbation of the disease in adult patients with non-severe COVID-19 (24). By examining the clinical findings of 82,719 patients with coronavirus that resulted in the treatment of 4632 patients who died, Deng et al. considered old age and male gender as risk factors for mortality. It was also observed that the time from the onset of symptoms to the treatment center, the time from the onset of symptoms to laboratory confirmation of COVID-19, and the duration of onset of symptoms to the patients' hospitalization of were directly related to higher mortality (30).
The retrospective nature of the study, lack of recording all data accurately, and lack of follow-up of discharged patients were among the limitations of this study. On the other hand, the high sample size of patients and the study of various factors were among the strengths of this study. Using the results of the current study can be effective in physicians' clinical decisions and also policy makers. However, performing multicenter and prospective studies with larger sample sizes and assessing other factors, especially the effect of vaccination, as well as the drug doses and their complications, can be valuable.