key: cord-354113-j8odxs1h
authors: Miao, Congliang; Zhuang, Jinqiang; Jin, Mengdi; Xiong, Huanwen; Huang, Peng; Zhao, Qi; Miao, Li; Du, Jiang; Yang, Xinying; Huang, Peijie; Hong, Jiang
title: A comparative multi-centre study on the clinical and imaging features of comfirmed and uncomfirmed patients with COVID-19
date: 2020-03-24
journal: nan
DOI: 10.1101/2020.03.22.20040782
sha: 
doc_id: 354113
cord_uid: j8odxs1h

Background Previous studies had described the differences in clinical characteristics between ICU and non-ICU patients. However, seldom study focused on confirmed and unconfirmed groups. Our aim was to compare clinical and imaging characteristics of COVID-19 patients outside Hubei province between confirmed and unconfirmed group. Methods We retrospectively enrolled 163 consecutive adult patients with suspected COVID-19 from three tertiary hospitals in two provinces outside Hubei province from January 12, 2020 to February 13, 2020 and the differences in epidemiological, clinical, laboratory and imaging characteristics between the two groups were compared. Results This study enrolled 163 patients with 62 confirmed cases and 101 unconfirmed cases. Most confirmed patients were clustered (31, 50.0%) and with definite epidemiological exposure. Symptoms of COVID-19 were nonspecific, largely fever and dry cough. Laboratory findings in confirmed group were characterized by normal or reduced white blood cell count, reduced the absolute value of lymphocytes, and elevated levels of C-reactive protein (CRP) and accelerated Erythrocyte sedimentation rate (ESR). The typical chest CT imaging features of patients with confirmed COVID-19 were peripherally distributed multifocal GGO with predominance in the lower lung lobe. Compared with unconfirmed patients, confirmed patients had significantly higher proportion of dry cough, leucopenia, lymphopenia and accelerated ESR (P<0.05); but not with alanine aminotransferase, aspartate aminotransferase, D-dimer, lactic dehydrogenase, and myoglobin (P>0.05). Proportion of peripheral, bilateral or lower lung distribution and multi-lobe involvement, GGO, crazy-paving pattern, air bronchogram and pleural thickening in the confirmed group were also higher (P<0.05). Conclusions Symptoms of COVID-19 were nonspecific. Leukopenia, lymphopenia and ESR, as well as chest CT could be used as a clue for clinical diagnosis of COVID-19.

Since December 2019, a cluster of pneumonia cases with unknown etiology were reported in Wuhan, in the Hubei province of China (1) . Scientists quickly identified the pathogen from infected patients respiratory epithelial cells and named it as severe acute respiratory syndrome corona virus 2 (SARS-Cov-2)(2). SARS-Cov-2 belongs to beta coronavirus and has 80% similar genetic sequence to severe acute respiratory syndrome (SARS) (3) . SARS-Cov-2, as a pathogenic microorganism for a new infectious disease, is currently not well understood by scientists.

With the spread of the epidemic, 2019 coronavirus disease , the new disease caused by SARS-Cov-2, broke out nationwide and worldwide, especially China, Italy, South Korea, Iran. As to March 10, 2020, a total of 80924 laboratory-confirmed cases had been reported in China, and 32778 confirmed cases overseas, which represents a trend of global spread(4). On 11 March 2020, the world health organization declared the COVID-19 as a global pandemic. Theoretically, the most effective strategy for epidemic is early diagnosis, quarantine and treatment. Therefore, how to diagnose COVID-19 early is of great importance. It's now the period of seasonal influenza, and the clinical symptoms of COVID-19 are similar to common respiratory diseases (influenza, common cold, viral pneumonia, etc.), which indicates the differential diagnosis are difficult for clinicians. At present, the diagnostic gold standard for studies had described the differences in clinical characteristics between ICU and non-ICU patients (7) (8) (9) (10) , however very few scientists focused on confirmed and unconfirmed groups(11). Therefore, we described and compared the epidemiological history, clinical, laboratory characteristics and imaging features between confirmed and unconfirmed COVID-19 groups aim to providing a reference for the COVID-19 differential diagnosis, prevention and treatment.

In this retrospective multi-center study, 163 consecutive and suspected adult patients were enrolled from three tertiary hospitals in two provinces outside Hubei province of China. Those patients who visited fever emergency clinics at Shanghai General Hospital, High-tech hospital (First Affiliated Hospital of Nanchang University) and People's Hospital of Yinchun City from January 12, 2020 to February 13, 2020

were arranged for laboratory examinations and chest computed tomography (CT). Each suspected case was quarantined in separate rooms after consultation. Patients were transferred to a specialized hospital after diagnosis. This study was approved by the Ethics of Committees of Shanghai General Hospital Affiliated to School of Medicine of Shanghai Jiao Tong University. Informed consent for this retrospective study was waived.

No patient and public were involved in this study

All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in We retrospectively collected demographic data, medical history, epidemiological, clinical, laboratory, and CT imaging characteristics of all suspected patients on admission from medical records. Laboratory examinations consisted of blood routine, liver and renal function, electrolyte, coagulation testing, lactate dehydrogenase (LDH), creatine kinase, myoglobin, and troponin I, C-reactive protein (CRP), procalcitonin, erythrocyte sedimentation rate (ESR). We evaluated the presented imaging features (including lesion morphology and distribution features) of all patients with chest CT on admission.

Nasopharyngeal swabs or sputum specimens were collected and sent to the local center for disease control and prevention (CDC) for detection of SARS-Cov-2 by RT-PCR tests. Patients with first negative results should receive repeated tests in an interval of at least 1 day. We used forward primer, reverse primer and probe target to envelope gene of SARS-Cov-2. The sequence of forward primer was 5ʹ-TCAGAATGCCAATCTCCCCAAC-3ʹ; The sequence of reverse primer was 5ʹ-AAAGGTCCACCCGATACATTGA-3ʹ; and The sequence of the probe was 5ʹCY5-CTAGTTACACTAGCCATCCTTACTGC-3ʹBHQ1. Conditions for the amplifications of the real-time RT-PCR were 50°C for 15 min, 95°C for 3 min, followed by 45 cycles of 95°C for 15 s and 60°C for 30 s.

All patients underwent chest CT scan in three hospitals of two provinces in China, 64 patients from Shanghai General Hospital were scanned on SOMATOM Definition All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in Optima 670 CT scanner, GE. Examination followed the normal chest protocols. CT scans were performed during end-inspiration with the patient in the supine position.

Overall scan time is 2s, and slice thickness for reconstruction is 1.25 mm. All the reports were issued after two radiologists reviewed the CT images independently and would be concluded by a chief radiologist when opinions diverge.

All patients with suspected COVID-19 enrolled in this study were diagnosed according to WHO interim guidance(12). Nasopharyngeal swabs or sputum specimens were collected for RT-PCR tests. All the suspected cases were divided into confirmed and unconfirmed groups according to the results of real-time RT-PCR tests. The confirmed group was defined as a positive result of at least one RT-PCR tests for SARS-Cov-2. The unconfirmed group was defined as all results of RT-PCR tests were negative.

The data of patients were recorded by Epidata. Normally distributed continuous variables were described as mean ± SD ( s x  ) and skewed distribution was expressed as the median (interquartile range). Continuous variables were compared using independent t-test if they are normally distributed; otherwise, the Mann-Whitney test was used. Categorical variables were described as frequency rates and percentages.

Proportions for categorical variables were compared using the chi-square test or the All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. . https://doi.org/10.1101/2020.03. 22.20040782 doi: medRxiv preprint clustering diseases and dry cough. It was found that proportion of males and productive cough in the confirmed group were less than those in the unconfirmed group (P<0.05), while the remaining variables were not significant (P>0.05).

The laboratory findings of patients are summarized in the Table 2 . On admission, lymphocytopenia was present in 35.5% of the confirmed group, and leukopenia in 24.2%. Most of the confirmed patients had elevated levels of CRP and ESR. Compared with unconfirmed group, confirmed group had significantly lower white blood cell count, neutrophil count and the absolute value of lymphocytes. It also had higher proportion of leukopenia and lymphopenia. ESR and potassium on admission were higher in confirmed group than unconfirmed group, while other laboratory findings did not significantly differ between groups (P>0.05).

The CT imaging features on admission are shown in Table 3 . On admission, 9 patients did not have CT imaging abnormality in confirmed group. In confirmed group, 42 (67.7%) patients had bilateral lung involvement, 34 (54.8%) showed peripheral distribution, and 46 (74.2%) showed more than 2 affected lobes. Two lobes and all lobes involved were more common, with 18 cases (29.0%) and 13 cases (21.0%) respectively.

Compared with unconfirmed patients, confirmed patients had significantly higher proportion of peripheral, bilateral or lower lung distribution and multi-lobe involvement (P<0.05). The most common patterns seen on chest CT in confirmed group All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in 19 .4%) and pleural thickening (12 cases, 19.4%) (Figure 1 ). Cavitation, pleural effusion, lymphadenopathy and pulmonary fibrosis were rare. Proportion of GGO, crazy-paving pattern, air bronchogram, and pleural thickening in the confirmed group were also higher (P<0.05). The remaining variables were not (P>0.05).

This study showed that most patients with COVID-19 had pneumonia, and the most common symptoms at onset of illness were fever, dry cough, myalgia or fatigue.

Less common symptoms were diarrhea, headache, sore throat, upper airway congestion and a small number of severe patients developed chest tightness and dyspnea, indicating that the target cells might be located in the lower airway. This was consistent with the results of previous studies(7-10, 13-15). There were no significant differences in initial clinical symptoms between in Hubei province and outside Hubei province. These nonspecific symptoms are shared by winter respiratory diseases caused by bacteria and viruses, especially influenza. Influenza are usually characterized by fever, myalgia, headache and dry cough, most of which are self-limiting but may also progress to severe conditions, such as pneumonia, myocarditis and death(16, 17). In addition, severe acute respiratory syndrome corona virus (SARS-CoV) and Middle East respiratory syndrome corona virus (MERS-CoV) also caused similar clinical symptoms, but more frequent diarrhea symptoms (18, 19) . To the best of our knowledge, this was the first multi-center study to compare the clinical features between confirmed group and unconfirmed group. All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. . https://doi.org/10.1101/2020.03. 22.20040782 doi: medRxiv preprint This report demonstrated that the incidence of dry cough in confirmed group was significantly higher than that in unconfirmed group, but the clinical symptoms of patients with COVID-19 were nonspecific. Therefore, clinical symptoms alone were difficult to distinguish from winter respiratory diseases.

Our study showed that the white blood cell count and the absolute value of lymphocytes in confirmed group was significantly lower than that in unconfirmed group. Qin et al demonstrated that lymphocytes counts in most severe COVID-19 patients was reduced, which suggests that SARS-CoV2 might impaired immune system and mainly damaged lymphocytes, especially T lymphocytes (20) . This was similar to SARS-CoV, which spread through the respiratory mucosa and infect other cells, triggering a series of inflammatory responses and cytokine storm, resulting in changes in lymphocytes (21) . Therefore, the reduced white blood cell count and lymphocytes could be used as a reference index for clinical diagnosis of COVID-19. In addition, the ESR of the confirmed group was significantly higher than that of unconfirmed group, while there was no statistical difference in CRP and procalcitonin between the two groups. Therefore, ESR could help clinicians distinguish between COVID-19 and winter respiratory diseases. Although previous studies had shown that some patients with confirmed COVID-19 had abnormal alanine aminotransferase (ALT), aspartate aminotransferase (AST), LDH, D-dimer, myoglobin and troponin I, but there was no statistical significance between the two groups in this study. The underlying reason might be that the majority of patients with COVID-19 outside Hubei province were mild infections, with a small proportion of critically ill cases, while hepatic injury, All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. . https://doi.org/10.1101/2020.03. 22.20040782 doi: medRxiv preprint coagulation activation, myocardial injury were common in critically ill and severe cases.

This result was contrary to a recent study. Zhao et al showed that the levels of liver function associated markers (ALT, AST and LDH) were significantly higher in confirmed group than in unconfirmed group, but the sample size of the study was very small(11). Therefore, these laboratory indicators might not provide reference for the differential diagnosis of COVID-19 outside Hubei province.

The CT imaging features of COVID-19 are diversity. SARS-Cov-2 belongs to β coronavirus family, which causes pneumonia with similar imaging features to other coronavirus pneumonia, such as SARS and Middle East respiratory syndrome (MERS) (22, 23) . Our study showed that the typical CT imaging features of COVID-19

were peripherally distributed multifocal GGO with predominance in the lower lung lobe.

However, it still had specific imaging characteristics, especially compared to that of influenza A and influenza B. While the manifestations of seasonal influenza are small patch GGO and consolidation with subpleural and/or peribronchial distribution on chest CT (24) . Our study indicated that the proportion of GGO, crazy-paving pattern, air bronchogram, and pleural thickening in the confirmed group was significantly higher than that in the unconfirmed group. In terms of the distribution of lesions, the proportion of bilateral, subpleural, lower lung distribution and multi-lobe involvement in the confirmed group was significantly higher than that of the unconfirmed group.

Considering the high incidence of seasonal influenza, a recent study showed that the most common etiology in all suspected cases was influenza virus infection(25). Therefore, chest CT could become an effective clinical diagnostic tool for screening All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. Our advantage was that this was the first multi-center study to compare the clinical and imaging features between confirmed and unconfirmed groups. Comparison of the clinical and imaging features between the two groups may help clinicians to differentiate COVID-19 from other pathogen infections and then to screen patients with highly suspected cases.

There are several limitations in our study. First, although the RT-PCR test is the current gold standard for the diagnosis of COVID-19, it might still present a certain false-negative rate after repetitions. This is mainly due to the fact that the test samples are mostly pharynx swabs rather than bronchoalveolar lavage fluid (BALF) and RNA All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in Therefore, we did not further compare the differences between COVID-19 and specific pathogen infections. 

The authors state that this work has not received any funding. All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in 

Provenance and peer review Not commissioned; externally peer reviewed.

ORCID iDs Jiang Hong http://orcid.org/0000-0002-3745-5549 All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. perpetuity.

preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in

The copyright holder for this this version posted March 24, 2020. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in GGO, ground glass opacity A, GGO with bilateral and subpleural distribution; B, crazy-paving pattern with subpleural and bilateral lower pulmonary distribution; C, GGO; D, GGO with bilateral and subpleural distribution; E, GGO with crazy-paving pattern and air bronchogram; F, GGO with consolidation; G, GGO with air bronchogram and subpleural distribution; H, GGO with unilateral and subpleural distribution All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted March 24, 2020. . https://doi.org/10.1101/2020.03. 22.20040782 doi: medRxiv preprint 

Outbreak of pneumonia of unknown etiology in Wuhan, China: The mystery and the miracle

A Novel Coronavirus from Patients with Pneumonia in China

Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding

Coronavirus disease 2019 (COVID-19)

Chest CT for Typical 2019-nCoV Pneumonia: Relationship to Negative RT-PCR Testing

Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases

Clinical features of patients infected with 2019 novel coronavirus in Wuhan

Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China

Characteristics of COVID-19 infection in Beijing

/18, in the Islamic Republic of Iran

The severe acute respiratory syndrome. The New England journal of medicine

Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. The Lancet Infectious diseases

Dysregulation of immune response in patients with COVID-19 in Wuhan, China

T-cell immunity of SARS-CoV: Implications for vaccine development against MERS-CoV

Middle East respiratory syndrome coronavirus (MERS-CoV) infection: chest CT findings

Thin-section CT of severe acute respiratory syndrome: evaluation of 73 patients exposed to or with the disease

Viral pneumonias in adults: radiologic and