Are Patients with Elevated Inammatory Indications are at Higher Risk for Developing the Severe form of COVID-19?


 BackgroundSince December 2019, when SARS-CoV-2 emerged with a cluster of unknown pneumonia cases in Wuhan city and rapidly spread throughout in worldwide and Iran, data have been needed on the clinical and diagnostic features of the affected Iranian patients.MethodsWe extracted data regarding 233 patients with laboratory-confirmed COVID-19 from Buali Hospital in Iran; clinical/praclinical and inflammatory indexes data were collected and analyzed. The data of laboratory examinations and chest CT findings were compared between death and non-severe patients.ResultsThe mean age of the patients was 49 years, (63%) of the patients were male. The acute respiratory distress syndrome occurred in 64 patients, including 53 who were admitted to the ICU and underwent invasive mechanical ventilation, and 28 who died. On the admission in death group, lymphopenia (79%), neutrophilia (79%), and thrombocytopenia (21%) were usually observed. Most patients had a high SII index of > 500 (68%), increased CRP level (88%). A high level of inflammatory index’s such as NLR, PLR and SII in death comparison with moderate groups were observed (P < 0.001). The most common symptoms were fever (70%) and cough (63%) on admission. Headache was uncommon (11%). On admission, ground-glass opacity with consolidation (mixed) was the most common radiologic finding on chest CT (51%). No radiographic or CT abnormality was found in 15 of 204 patients (7%). In ConclusionThese patients often presented without fever, and some did not have abnormal radiologic findings. Elevated NLR, PLR and SII can be considered as prognostic and risk stratifying factor of severe form of disease.

con rmed cases in other countries also reached 5,304,772 of which 342,029 were dead, and 1,184,459 were cured according to o cial data from the WHO.
Many medical studies have shown that COVID-19 patients have obvious in ammatory responses, accompanied by a decrease in the absolute count of lymphocytes in the peripheral blood circulation and an enhancement in the number of neutrophil [3]. Most patients with SARS-CoV-2 infection were mild/moderate that are characterized by fever, malaise, cough, upper respiratory symptoms, and/or less common features of COVID-19, in the absence of dyspnea. Most of these patients do not need hospitalization [4]. However, nearly 15-20% of cases would develop severe illness, which has laboratory risk factors for disease progression. Some of these patients need hospitalization in intensive care unit (ICU) [5,6]. Organ dysfunction including acute respiratory distress syndrome (ARDS), shock, acute cardiac injury, and acute renal injury, can happen in 5% of severe cases with COVID-19 [4,7]. Since most COVID-19 infected patients were detected with pneumonia and feature computed tomography (CT) scan imaging patterns, radiological (X ray) examinations have become vital diagnostic method in early detection's and assessment of ill course [8]. Typical chest CT scan ndings of COVID-19 include peripherally distributed multifocal ground-glass opacities (GGOs) with patchy consolidations and posterior part or lower lobe involvement predilection. Increasing numbers, extent and density of GGOs on CT scan indicate disease progression [7,9]. These pathological damages might be attributable to indirect cytokines release syndrome (CRS) e.g. interleukin (IL)-1, IL-6 and TNF-α initiated by immune system and direct attack from SARS-CoV-2 [10].
In this study, we compared the clinical/diagnostic features, imaging manifestation and outcomes of disease in mild/moderate illness and severe (as result some death) COVID-19 patients, to discover the useful prognostic index for an accurate individualized assessment of the COVID-19 severity.

Design and Participants
This case-control study was performed in referral hospital for COVID-19 patients in Zahedan, Iran.
Participants included 233 hospitalized patients with con rmed COVID-19 infection in our hospital from February 29, 2020 to May 24, 2020. The protocol of the present study was approved by the ethical committee of ZAUMS, and written consent was obtained from the patients or their guardians. The clinical classi cations in this study are as follows, mild/moderate: with the respiratory distress and means oxygen saturation ≤ 93%; severe with one of the following conditions: respiratory failure occurs and requires mechanical ventilation, shock occurs or ICU admission is required for combined organ failure.

Data collection
From all suspected patients for SARS-CoV-2 infection that were admitted to the hospital for hospitalization in infectious unit, oro-and naso-pharyngeal swab spacemen were taken and stored in VTM medium (virus transport medium) and the con rmed diagnosis of SARS-CoV-2 was de ned as a positive result of real time reverse transcriptase polymerase chain reaction (RT-PCR). In addition fasting venous blood were collected for paraclinical assessment.
All of the patients, routine blood biochemistry parameters, complete cell blood count (CBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and chest radiological/CT scan were performed. Routine blood biochemistry analyses included liver function test (LFT), renal function, electrolytes test, lactate dehydrogenase (LDH), myocardial enzymes e.g. creatine phosphokinase (CPK), D-Dimer and status of other virus infection.

In ammatory indications
In ammation index were detected using speci c parameters of blood analysis. These indexes were as follows: neutrophil to lymphocyte ratio (NLR) by dividing the neutrophil absolute count to the lymphocyte absolute count and platelet to lymphocyte ratio (PLR) by dividing the platelet count to the lymphocyte absolute count were de ned. Systematic immune-in ammation index (SII) was calculated base on as platelet count multiplied NLR (per µL).

Statistics analysis
All of the data presented by mean ± standard error of mean (SEM). Analysis was performed with the IBM SPSS version 23.0 statistical software package, with an independent sample t test for comparison between groups. Descriptive statistics were performed to determine the patient's diagnostic and clinical features. P-Value less than 0.05 was indicated statistically signi cant.

Results
A total of 1,911 patients with a mild/moderate or severe symptoms of COVID-19 during 3 month were admitted in our hospital, of these cases, 233 patients with con rmed diagnosis of COVID-19 with RT-PCR method. About 12% (28/233) of patients with con rmed diagnosis of this disease were dead. In the same time, the rate of mortality for all causes in this hospital was 2.04% (39/1911). Of the 233 patients with SARS-CoV-2 infection included in this study, 205 were diagnosed as mild/moderate or severe (hospitalized group) and 28 were as severe on admission in hospital and expire (death group, [see Clinical and laboratory ndings As indicated in Table 2, on the admission, fever < 38ºc (70%) and dry cough (63%) were the main common symptoms. In addition, dyspnea (62%), SPO 2 <%93 (55%) and muscle or chest pain (32% / 22%) were observed in patients. In the death groups, most of the infected patients were men (twenty, 71%); more than half had underlying diseases (sixteen, 64%), including hypertension (seven, 25%), diabetes (six, 21%), and cardiovascular disease (three, 11% [ Table 3]).
Although, the genomic sequence of SARS-CoV-2 has been shown to be relatively different from the six other coronavirus subtypes but it can be classi ed as beta coronavirus [12]. In case of SARS-CoV and MERS-CoV, the viruses can be transmitted directly from civets and dromedary camels to humans, respectively, and bats were considered as the origin of both viruses, but the origin of SARS-CoV-2 is still not clear and needs further investigation [12,16]. Rate of transmission is not exactly documented for SARS-CoV-2; however, human to human transmission has been evidenced [7,12]. In concert with previous reports, it has been revealed that the clinical manifestations of COVID-19 mimic those presented in SARS-CoV [4,7,12,17]. Fever and cough were the most predominant symptoms manifested in 80% and 70% of our patients respectively. However, gastrointestinal upsets were infrequently presented (10%), which suggests a different viral tropism and pathogenesis in comparison with SARS-CoV, MERS-CoV, and seasonal in uenza [7,[18][19][20]. The frequency of afebrile patients suffering from COVID-19 (20%) is more frequent than in SARS-CoV (1%) and MERS-CoV infection (2%) [7,15] implying that presence of fever is not a trustworthy nding to be focused in case de nition because afebrile patients will be missed. Similar to previous reports [4,7,12], reduced absolute lymphocytes count, and elevated level of CRP and ESR were the main laboratory ndings. Damage to T lymphocytes might be a contributing factor leading to substantial decrease in total lymphocytes count and exacerbation of patient's status [21] as we observed statistically signi cant abnormalities in laboratory ndings (including lymphopenia, elevated NLR, PLR and SII) of patients who expired when compared with non-severe disease. In consistent with our result, a previous study conducted by Liu, et al [3], documented NLR as the independent risk factor for prediction of severe illness in patients with SARS-CoV-2 infection which should rapidly hospitalized in ICU. So that, in 50% of patients with age ≥ 50 who had NLR ≥ 3.13 severe form of the disease were observed [3,10].
Furthermore, in another study, a correlation between elevated PLR and the length of hospitalization day was evidenced and it has been concluded that if PLR increased more during treatment, the patient needs longer hospitalization day and had greater possibility of severe pneumonia [22]. It is concluded that lymphocytes, especially T lymphocytes, are the main cell to be targeted and consumed by SARS-CoV-2, as does SARS-CoV [21]. Virus particles pass across the respiratory mucosa and attack other cells, stimulate a cytokine storm in the body, and generate a cascade of immune responses, leading to changes in peripheral white blood cells and immune cells such as lymphocytes [12]. Patients who suffered from severe form of COVID-19 (18%) required ICU hospitalization and oxygen therapy. Consequently, ARDS and septic shock progressed rapidly in some of our patients, which were eventually followed by multiple organ failure and death. As a result, level of creatinine, BUN and total/direct bilirubin were signi cantly increased in deceased patients when compared to alive patients which suggesting acute kidney and liver injury in our deceased patients similar to whatever evidenced in former report [23]. Therefore, early diagnosis and promptly treatment initiation of critically ill individuals is issue of crucial importance [12].
Only one patient in our investigation was medical worker. The mortality rate of SARS-CoV and MERS-CoV has been reported as more than 10% and 35%, respectively [24,25]. The rate of mortality in our SARS-CoV-2 infected population was 12%, resembling to previous study [12]. Nonetheless, the rate of deaths might increase because many patients are still hospitalized. It necessary to be noted that since patients who had uncomplicated illness and who did not need medical attention were not included in our study, the rate of case fatality in a real world scenario might be even lower. COVID-19 was more commonly observed in men than women (63% vs 37%) in our study. This gender preponderance was in agreement with previous studies [4,7,12]. Also, higher rate of MERS-CoV and SARS-CoV infection were documented in males than females [26,27]. The lower frequency rate of COVID-19, MERS-CoV and SARS-CoV infection in females are thought to be attributed to the protection originating from sex hormones and X chromosome, which play contributing role in innate and adaptive immunity [28]. Additionally, it has been documented that COVID-19 is more probably to occur in older adult males due to weaker immune functions particularly those with chronic underlying diseases [12]. Our patient's age ranged from 16 to 90 years with a mean age of 49 years. The data was in consistent with the previous studies which more and less reported similar mean age [7,12]. The highest positive rate of COVID-19 RT-PCR was observed in age group 40-60 years. Since, our aim was to investigate the COVID-19 patients with positive RT-PCR as reference method, of 629 hospitalized patients who were clinically suspected cases of COVID-19 and also had initial positive CT scan suggesting COVID-19, only small quantity of our subjects had positive RT-PCR assay suggesting two scenarios: rst, it may be indeed be true to say that the sensitivity rate of RT-PCR is as low as 37% which somehow has been also demonstrated in previous studies and may be justi ed by a list of confounding factors which is regarded to in uence the result of RT-PCR and lead to false-negative including: improperly collected, transported or handled specimens, presence of ampli cation inhibitors in the specimen or inadequate numbers of organisms [11,29,30]. Second, due to the overlap of CT imaging patterns between COVID-19 and other viral pneumonia, false-positive cases of COVID-19 may be identi ed on chest CT scan [11]. Nevertheless, given the rapidly spreading of COVID-19, the priority should be to identify and isolate any suspicious CT scan case in order to administer appropriate treatment. By the way, in the context of disease control, some false-positive cases may be acceptable [11]. Therefore, one negative result of RT-PCR does not rule out SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions and treatment.

Conclusions
As a result, serially performance of RT-PCR test along with CT scans is highly recommended. In patients with negative RT-PCR tests, a combination of a history of direct contact with proven cases, clinical manifestations and typical CT imaging features should be collectively used to detect patients with Availability of data and materials The datasets used or analyzed during the current study, as well as the study protocol, are available from the corresponding author on reasonable request.
Competing Interests: No con ict of interest Ethics approval and consent to participate: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study protocol was approved by the ethics committee of Zahedan University of Medical Sciences (IR.ZAUMS.REC.1399.) and written consent was obtained from the patients or their guardians.

Consent for publication
Not applicable.