Clinical characteristics and Mortality risk factors among COVID-19 patients in Qom–Iran; The results of a Retrospective Cohort study

Background & Aim Coronavirus 2019 (COVID-19) outbreak in the Middle East was initially reported in Qom-Iran. Clinical and epidemiologic and mortality risk factors details have not been already fully explained. In a retrospective study, the hospitalized adult patients with laboratory diagnosed COVID-19 between February 25 to March 20, 2020 were enrolled. A checklist including demographic, clinical, laboratorial, imaging, and treatment data was completed for each of the participant. The data were extracted from electronic medical records. In case of lack of information, a member of the research team contacted them via phone. All the dead patients and the rst one hundred survived patients with these criteria were enrolled in the study. Outcome dened as death or discharge of patients.

This is a retrospective study including hospitalized adult patients between February 25 to March 20, 2020 in Shahid Beheshti referral hospital, Qom-Iran. This hospital is one of the designated hospitals for COVID-19. All the admitted adult patients with de nite outcome in this period were considered. The patients who were diagnosed with the COVID-19 according to WHO guidelines were selected. Detection of the RNA of the virus was considered as the con rmed positive result. Also, other non-de nite results were considered as highly suspected patients who did not enroll in our study. The outcome was de ned as death (nonsurvivor) or discharge (survivor). All dead patients as well as the rst one hundred living patients were enrolled in our study.
The criteria for discharge were the improvement of the general status and respiratory symptoms, absence of fever for at least 3 days, chest CT scan improvement in both lungs and at least one time throat-swab or nasal -swap samples negative for SARS-CoV-2 RNA assessment.
Data Acquisition: The data were obtained retrospectively from patient's medical records in the hospital who had been admitted due to COVID-19 infection. According to WHO recommendation, a questionnaire including demographic, anthropometric, clinical presentation, laboratorial, and imaging data was designed. It was lled up for each patient by 2 trained residence of internal medicine. In case of lack of data, a member of the team called him/her to complete the questionnaire. Regarding dead patients, the information was asked from one of the rst-degree relatives. The lled-up questionnaire was approved by three experts. Two of them were professors of internal medicine and the third one was an epidemiologist.
Laboratorial Data: Obtaining the specimens, transferring to the central laboratory and also the lab safety issues were according to the WHO recommendations (WHO laboratory testing strategy recommendations for COVID-19: Interim guidance2020).
As a standard method, venous blood samples were obtained from each patient in the rst day of admission. Complete blood count (CBC) with differential was measured ( by Sysmex K1000, Hamburg, Germany).Also the alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), uric acid (UA), blood urea nitrogen (BUN), creatinine, C-reactive protein (CRP), were measured by using the diagnostic kits from Pars Azmoon Company (Pars Azmoon Co., Tehran, Iran) .
COVID-19 one-step Real-time PCR was performed by the referred diagnostic laboratory, which was con rmed by the ministry of health based on universal protocols. A nasopharyngeal swab into viral transport media (VTM) used for commercial RNA extraction according to manufacturer's instructions.
All patients have undergone a standard high-resolution CT scan (HRCT) of chest. The results of the imagines were acquired via electronic reports of each patient.

Statistical analysis
Mean (SD) and n (%) were presented for continuous and categorical variables, respectively. Independent ttest was applied to compare normally distributed data, while Mann-Whitney U test was used for nonnormally distributed ones. Chi-square or Fisher's exact test was used to evaluate differences between survivors and non-survivors.
Univariate and multivariate (with backward method) logistic regression models were used to examine the association between different variables and in-hospital death related to COVID-19. Some variables were excluded from univariate analysis if they were self-reported, if they hadn't enough number of events, and if the association between them and death status were not signi cant. All the statistical analyses were done using STATA software version 15 and p<0.05 was considered as statistically signi cant.

Results:
Totally 650 patients were admitted to the Shahid Beheshti general hospital, in the mentioned period. We have just selected the patients who were admitted and diagnosed with COVID19 with the con rmed outcomes. The patients without available key reports were excluded. Finally, we enrolled all non-survivor patients and one hundred survived patients in this study.  Hypertension and diabetes type 2 were the most common co-morbidities in these patients ( Table 1).
Moreover, the frequent complications were respiratory failure, acute respiratory distress syndrome (ARDS), acute kidney injuries and acidosis with 143 (71.5%), 105 (52.5%), 67 (33.5%) and 48 (24%) cases. Additionally, coagulopathy was common in non-survived patients 40 (40%) ( Table 4). In the univariate analysis, we have observed that older patients had higher odds of death (Table 5). In addition, having hypertension, having CVD, WBC, neutrophil level, lymphocyte level, hemoglobin level, BUN, creatinine level, CRP, INR, pH level, SpO2 level, patchy consolidation, ground glass and patchy in ltration were also related to death (Table 5). In further analysis, two hundred patients with complete data for selected variables were included in the multiple logistic regression model (with backward method). We have observed that Hb level (≤ 10), neutrophil count (> 7.7), creatinine level (≥ 1.3), SpO2 level (< 90), and patchy consolidation were related to increased odds of death after adjustment for other variables (Table 5).

Discussion:
The present study is one of the primary reports with a large number of COVID-19 patients in Iran. We have observed that Hb, neutrophil, BUN, SpO2, and patchy consolidation in the CT assessment at admission time are statistically related to mortality. Although other factors may effect on outcome(Table5).
Interestingly, just one quarter of our study patients revealed a history of contact with suspected patients, which is comparable with the another nding (11). The virus transmission rout remains an important issue, which may play a major role in development of disease. Besides the common routs, nosocomial, fecal-oral, and aerosol transmission should be considered (12)(13)(14). Nosocomial transmission of the disease may occur mainly during the incubation period as well as close contact with patients with minimal symptoms (5,(15)(16)(17). Although the outbreak in China has been started via zoonotic transmission, in the city of Qom, the main rout of transmission seems to be person-to-person. None of our patients had a history of travel to China in the last two months before the outbreak and had a history of wild animal contact. All of our patients have inhabited in Qom too. Indeed, familial cluster was common in the city that close contact have happened. We should emphasize that transmission can be occurred by asymptomatic cases during incubation period even by potential routs such as saliva and urine (11,18).
The important point is the need to use well protective techniques, isolation and laboratory assessment, particularly for the healthcare staff. Moreover, in present study we did not estimate the virus reproductive value but according to the contamination speed, it may be higher than the previous reported data. Earlier studies indicated that the reproductive value (R 0 ) of COVID-19 was estimated to be between 2 and 3.5. It means that one infected patient could infect 2 to 3.5 individuals (17,19,20).
The gender distribution in our study shows that the male gender is prominent. Although there was no signi cant association between gender and the outcome. This is similar to the previous reports (21,22).
Furthermore, we have observed the association of mortality with increasing age, although it was not an independent risk factor for the mortality and lower than former study of China. In this context, previous studies veri ed that aging has a positive relation with mortality rate in MERS, SARS as well as COVID-19.
It may be secondary to either sever pneumonia or its own associated morbidities during elderly (23) (2,11). Recent report of CDC team for COVID-19, revealed that 80% of deaths are secondary to COVID-19 and it was among adults aged ≥ 65 years (24). In a pathophysiology view, studies on immune system in elderly patients disclosed the impaired T and B cell function. In fact, at older age the alteration of cytokines has a key role in the immune system function, as excess production of type 2 cytokines has been reported. Altogether, cytokines dysregulation could lead to defect control of viral infection and in ammatory responses (25,26).
In present study, the main presentations were dyspnea and shortness of breath, cough, and fatigue/weakness. Bilateral opacities in CT scan assessments were particularly frequent in patients.
Among them, bilateral consolidation associated signi cantly with risk of mortality. The relation between drop of SpO2 level with poor outcome may work in this context. The CT scan imaging is one of the principal and rapid diagnosis in COVID-19 for initiation of treatment and follow-up in order to nd the healing changes in lungs. It was stated that consolidation with ground glass feature in both lungs were more prominent, particularly in dead patients, which was similar to our ndings (27)(28)(29). The mechanism of lung damage needs more studies. It may be due to direct invasion of virus or in ammatory cascade, altogether, there is a need for more studies in order to identify the exact imaging feature of the disease for prognosis estimation and improvement assessment.
Clinical presentations of our study patients have some differences with other studies (29,30). We have found fever more than 38 oc was not a common symptom. In this regard the 87 (43.5%) subjects were bril patients. This fact may reduce the predictive value of fever during surveillance. Moreover, number of patients with gastrointestinal manifestations at the time of admission was low and not signi cant differences between survivor and non-survivor patients regarding liver biochemistries has been observed.
However, recent studies indicated the close relationship of abnormal liver function tests with severity of COVID Neutrophilia (> 7.7count10 3 /µL ) was common among our patients that signi cantly associated with mortality. This is also consistent with the previous studies as it was observed that patients increased blood neutrophil counts had severe symptoms (35)(36)(37). In severe cases lymphopenia has a great potential prognostic value and neutrophilia involved in in ammatory process. Wu et al in Wuhan revealed that the risk of ARDS signi cantly associated with neutrophilia, as well as aging and coagulation dysfunction (38). Furthermore, almost all of non-survivor patients suffered from ARDS. In addition, we have revealed a strong signi cance association between low Hb level and poor prognosis. In previous studies Hb value was found to be signi cantly lower in COVID-19 patients with severe disease than in those with milder forms. Hb level may re ect the severity of disease and probably involved in pathophysiology of organ failure on these patients and worse clinical outcome. Decline of Hb level could be secondary of in ammation process (1,39). Therefore; regular assessment of CBC with differentiate at beginning and during patients' follow up, clinically would strongly recommended.
It is documented that patients with acute viral and bacterial pneumonia are at the risk of acute cardiac events during and after elimination of infection. Unfortunately, due to the outbreak emergency, patients were not regularly evaluated for cardiac enzymes or echocardiography. Hence, we did not have enough data regarding cardiac events. Among patients with COVID-19, many of them had underlying cardiovascular diseases and developed acute cardiac injury during the course of the illness (40). The mechanism has not been fully cleared but it can be due to neutrophils activity and in ammation process or direct invasion of pathogen (41,42). Moreover, it is documented that preexisting coronary heart disease can be associated with acute cardiac events and eventually poor outcome in respiratory viral infection such as in uenza (43,44).
In conclusion, this is a large study among patients with de nite outcome. In fact, COVID19 is a clinically complex virus that affects all the vital organs either via direct attack or in ammatory processes.
Shortness of breath or dyspnea and cough were the common and valuable clinical manifestations. Low value of Hb, neutrophilia, and high BUN along with consolidation in CT scan images were risk factors of mortality that need to pay more attention during surveillance of patients.

Appendix 1: De nition
Fever was de ned as the sublingual temperature more than 37·6 °C. Sepsis de ned as a life-threatening organ dysfunction caused by a dysregulated host response to the infection and septic shock is de ned as a subset of sepsis in which underlying circulatory and cellular metabolism abnormalities are profound enough to substantially increase mortality, according to the Third International Consensus De nition for Sepsis and Septic Shock (45). Acute kidney injury was diagnosed based on the KDIGO clinical practice guidelines (46). Acute respiratory distress syndrome (ARDS) was de ned as reported by the Berlin De nition (47). Coagulopathy was de ned as INR more than 1.3 or more than 3-second extension of prothrombin time (PT). Exposure history was de ned as exposure to people with suspected or con rmed COVID-19. Due to emergency circumstances some lab tests were not available.