Clinical characteristics of 276 hospitalized patients with coronavirus disease 2019 in Zengdu District, Hubei Province: a single-center descriptive study

In December 2019, a series of pneumonia cases with similar symptoms were reported in Wuhan, Hubei Province, China [1]. That pneumonia was later named coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO) [2]. The causative pathogen was identified as a novel enveloped RNA beta coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [3]. COVID-19 is highly contagious and spreads rapidly through human-to-human transmission [4‐6]. As of March 29, 2020, there were 81,470 confirmed COVID-19 cases and 3304 deaths in China, including 67,801 confirmed cases and 3186 deaths in Hubei Province, and 721,584 confirmed cases and 33,958 deaths worldwide. However, many infected people have not been counted owing to a lack of timely diagnosis. COVID-19 is a global pandemic. Therefore, a comprehensive and in-depth understanding of the epidemiological and clinical characteristics of COVID-19 is imperative for controlling the pandemic as soon as possible.

The number of COVID-19 cases in Wuhan was large, the spread was fast, and the fatality rate was high. Most of the clinical characteristics of COVID-19 have been summarized from the samples of patients in Wuhan [7]. Controlling the epidemic in the areas around the core COVID-19 outbreak region is an important link in blocking the spread of the disease. The Chinese government has enlisted many volunteer doctors to support hospitals in these key areas. However, there are few reports on the clinical characteristics of COVID-19 inpatients in these areas [8, 9]. Thus, this study collected clinical data for COVID-19 inpatients in Zengdu Hospital, a community hospital supported by 95 volunteer doctors and nurses from Jiangxi Province (about 300 miles from Zengdu District). We describe the epidemiology, clinical features, laboratory findings, imaging features, and outcomes of COVID-19 inpatients in Zengdu District, which is a 3-h drive from Wuhan City. We hope that our work will contribute toward an understanding of COVID-19 characteristics in the areas around the core COVID-19 outbreak region and provide a decision-making reference for epidemic prevention and control in similar areas.

Understanding the clinical characteristics of COVID-19 inpatients in the areas around the core COVID-19 outbreak region is very important for controlling the spread of COVID-19 and decision-making for epidemic control. Our study on 276 inpatients in Zengdu Hhospital confirms that COVID-19 patients in the areas surrounding the core COVID-19 outbreak region showed mainly mild and moderate illness with fever and lymphocytopenia as the main clinical features. Older patients (age > 60 years) or those with underlying comorbidities are at higher risk of deteriorating to critical status. The length of hospital-stay and antiviral treatment duration for COVID-19 were slightly longer than those in Wuhan.

All patients who tested positive for COVID-19 by RT-PCR in the study region were admitted to the hospital, regardless of the severity of the patients’ condition. There were several reasons why our hospital established such an admission standard. First, at that time, the outbreak was still in the early stage. The understanding of the epidemic situation in Zengdu District, a residential area approximately 3 h away from the core COVID-19 outbreak region, was very limited, and there was no clear evidence to determine which patients could be treated at home. Second, the representative area of Zengdu District was a key area to control the spread of the epidemic; therefore, it was necessary to treat as many diagnosed patients as possible. Third, at that time, Zengdu Hhospital was supported by 98 Jiangxi volunteer doctors (including most of the authors of this article) and extensive medical equipment. Hence, there were sufficient medical resources to treat all the diagnosed patients. Our admission criteria were formulated under such special circumstances, although this admission standard was different from the current international standard. Moreover, compared to studies in which only seriously ill COVID-19 patients were admitted, our admission criteria better reflect the disease characteristics in the area around the outbreak point, so as to provide a decision-making reference for hospitals in the residential area to decide which patients should stay at home for observation and which high-risk patients should be hospitalized in a timely manner.

The patients in Zengdu area show mainly showed mild and moderate illness, with a few patients showing severe and critical illness. In Wuhan, as the site with the most serious COVID-19 infection in China, many patients did not get timely diagnosis and treatment initially, and medical resources were insufficient to accommodate the sudden burst of patients. As a result, the proportion of severe cases reached 15.0–30.0% [14, 15], while the rate of severe disease in other regions was 3–10% [16, 17], similar to 5.1% in this study. This may be because, with the deepening of the understanding of COVID-19 and the formulation of relevant guidelines [18, 19], many patients were diagnosed and treated in a timely manner without deteriorating into severe disease. Besides, the difference in admission criteria was also a reason why the rate of severe disease in this study was significantly lower than that in Wuhan or abroad.

The early common symptoms of COVID-19 patients include fever, cough, sputum, and other symptoms of lower respiratory tract infection. As the most common symptom, in general, more than 80% of patients have a fever, but only 38.4% of the patients had a fever at the time of admission, which shows that the fever in many patients was intermittent. It also means a large number of patients with intermittent fever will be set free if instant body temperature readings are the only measure used for screening [2, 20]. The proportion of fever in critically ill patients increases significantly after hospitalization, and most of these new fever cases may be caused by secondary infection, so it is necessary for severe patients to receive antibiotics to prevent secondary infection [13].

COVID-19 patients over 60 years old were more likely to show deterioration into critical illness. Previous studies on severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) have confirmed that age was an important predictor of poor prognosis [20, 21], and similar conclusions were obtained for COVID-19 [22]. Data obtained by Nanshan Zhong et al. [23] and Zhongliang Wang et al. [14] showed that the age of severe patients was significantly older than that of non-severe patients. Consistent with these findings, among the patients we collected, the median age of severe patients was 65 years, while that of non-severe patients was 50 years. In addition, about 78.6% of the severe patients were more than 60 years old. These studies have shown that older COVID-19 patients have a poor prognosis.

COVID-19 patients with comorbidities were also likely to show deterioration [24]. The studies by Nanshan Zhong et al. and DaweiWang et al. [22] both showed high proportions of comorbidities in severe patients. A WHO survey reported that people with comorbidities had a higher risk of severe disease [25]. In a recent retrospective study of 25 death cases with COVID-19 [24], all of the deceased patients have comorbidities, which were considered to be one of the most important risk factors for death. In this study, 85.7% of the severe patients had comorbidities. This may be due to abnormal immune function and increased susceptibility to SARS-CoV-2 in patients with comorbidities [26, 27]. In addition, COVID-19 damage to the lungs can aggravate some comorbidities, such as chronic obstructive pulmonary disease. Antiviral drugs and glucocorticoids also have limited benefits for patients with comorbidities.

In terms of laboratory tests, 75% of patients had lymphopenia, and more obvious findings were noted in severe patients. The novel coronavirus can induce a cytokine storm and inhibit the generation of lymphocytes [28, 29], so lymphopenia is very common in patients with COVID-19. The low absolute value of lymphocytes can be used as a reference indicator for clinical diagnosis of novel coronavirus infections [6]. Lymphocytes showed a pronounced decline in severe patients than in non-severe patients, indicating that the degree of lymphocyte decline can be used to assess the severity of the disease [30], and that continuous decline of lymphocytes is also one of the indicators of disease deterioration [13]. In the absence of nucleic acid detection and CT, this can be an important tool for determining the severity of the disease. The length of hospital stay in this study was slightly longer than that in Wuhan, which was 11–12 days [23, 31]. This contradicted the finding that the length of hospitalization is positively related to disease severity because COVID-19 severity in this study was significantly lower than that in Wuhan. However, the allocation of medical resources is also an important factor affecting the length of hospitalization. The number of infected patients in Wuhan was large and medical resources were scarce, so the hospital had to discharge inpatients as soon as possible to treat newly admitted patients. The inpatient data collected in this study were from a community hospital that was supported by many Jiangxi doctor volunteers and medical supplies, which ensured sufficient medical resources. The characteristics of inpatients under this special medical setup were different from those at other hospitals. In particular, after the local epidemic is mostly controlled, some wastage of medical resources may be inevitable. For example, patients were allowed to stay in the hospital for some time to recover even after meeting the discharge criteria for COVID-19, which was not possible in the hospital in Wuhan. This was also the reason why the length of treatment for COVID-19 (14 days) is significantly shorter than the length of hospitalization (18 days). In addition, hospitals in Wuhan only accept patients who have been diagnosed as showing COVID-19, while hospitals outside Wuhan admitted many patients who were not diagnosed at admission and were also hospitalized for the 1–3 days it took for nucleic acid test results to arrive. Three studies from regions with sufficient medical resources [32‐34], namely Taizhou, Guangdong, and Shenzhen, can support our hypotheses since their median hospital stays were 18 days, 20 days, and 20 days, respectively, which were close to the results of this study.

This study has several limitations. First, since it is a retrospective study with a limited number of patients, some conclusions need to be verified by studies with more rigorous design and larger samples. Second, Zengdu Hhospital was a community hospital, and most of the critically ill patients had to be transferred to superior hospitals for treatment. we are temporarily unable to get information on the follow-up treatment and complications of these patients. Third, when calculating the incubation period, we excluded the unclear contact date, resulting in fewer patients included, and the potential memory bias will also affect our results. Fourth, our admission criteria were different from the current internationally recognized criteria, which limits comparability with other studies. However, our admission criteria were set in high-risk areas at the early stage of the epidemic to avoid the spread of the epidemic, which was essential and important. In addition, only PCR-confirmed COVID-19 patients were included in this study and asymptomatic infections without PCR confirmation were omitted, so the characteristics we described are only suitable for PCR-confirmed COVID-19 patients.

Most of the COVID-19 patients in Zengdu area had mild disease. Older patients with underlying comorbidities had a high risk of progressing to severe disease. A large number of patients with intermittent fever will be omitted by the temperature checks that are currently widely being deployed. The length of hospitalization and antiviral treatment for COVID-19 were slightly longer than those in the Wuhan area. This work will contribute to our understanding of the disease characteristics in the areas around the COVID-19 core outbreak point and provide reference data for decision-making for epidemic prevention and control in such special areas.