Current research indicates that SARS-CoV-2 is more than 85% homologous to bat SARS-like coronavirus (bat-SL-CoVZC45). Therefore, it is considered that COVID-19 was transmitted by bats, which needs further research confirmation. So far, we are not fully aware of the pathogenesis and the transmission route of the COVID-19 pneumonia, so we conducted a retrospective analysis on 69 cases of COVID-19 pneumonia in Suzhou, China.
This study includes 69 cases of COVID-19 diagnosed in the Suzhou Fifth People’s Hospital, which shows, similar to Chen’s study, patients with SARS-CoV-2 were mainly middle-aged and elderly, with a median age of 43 years (35.5, 59.0), of which 42 (60.9%) are males. 90% of the patients had a history of exposure to the Hubei epidemic area, with an incubation period of 2–14 days and the median incubation period of 7.0 days (4.0–10.0), which is also similar to similar to Wang’s study [9, 10]. 21.7% of patients had underlying chronic diseases, of which hypertension and diabetes account for a higher proportion of chronic diseases, and there was no significant statistical difference between the two groups (P༞0.05).
Fever is the most common clinical symptom of the COVID-19 pneumonia, with 62 (89.9%) cases of the 69 patients observed. Fever occurred in the early stage of the disease, among which 43 (62.3%) cases had body temperature ≤ 38.5℃, which was more common in Group A. There were 10 (55.6%) cases with body temperature ≥ 38.5℃ in Group B, which was significantly higher than that in Group A, and the difference was statistically significant (P༜0.05). In addition, the duration of fever in Group B was significantly longer than that of Group A, the median time for fever duration in Group B was 7.5 days (4.0-10.5), and the difference was statistically significant (P༜0.05). Cough (75.4%), chest tightness (63.2%), and fatigue (59.4%) were also common, among which chest tightness was more common in Group B while fatigue was more common in Group A, and the difference was statistically significant (P༜0.05). It is considered to be related to lung lobe invasion in severe patients. Diarrhea (14.5%) and muscle soreness (10.1%) were less common in patients, however, we still need to be alert to the patients who are mainly diagnosed with gastrointestinal symptoms, and pay attention to strengthening protection, and conduct SARS-CoV-2 nucleic acid testing timely for patients with a history of epidemiology.
The retrospective analysis of 69 patients with COVID-19 pneumonia indicates that 67 (97.1%) patients showed lung lesions on imaging, showing multiple sites of distribution, and lesions were seen in both lungs and subpleural area, mostly showed grinding glass density shadow, consolidation, interstitial change, small leaf interval thickening[12, 13](Fig. 1). The median time from illness onset to lesions progression in COVID-19 pneumonia patients was 3.0 days (2.0, 5.0); The median cumulative lung lobes number of lesions was 3.0 (3.0, 4.0), and the cumulative number of lung lobes in Group B was significantly higher than that in Group A, with statistically significant difference (P༜0.05). Laboratory data showed that the WBC, N%, and CRP of Group B COVID-19 pneumonia patients were significantly higher than those of Group A patients, and the differences were statistically significant (P༜0.05). It is considered to be caused by systemic inflammation which was relatively obvious in severe patients, but the possibility of bacterial infection or secondary fungal infection in some severe patients could not be ruled out. The absolute value of lymphocytes decreased significantly in 45% of COVID-19 pneumonia patients, especially in the Group B comparing with the Group A, with a statistically significant difference, suggesting that the cellular immune function decreased in early stage in COVID-19 pneumonia patients, especially in severe patients. A total of 20 (29.0%) patients had abnormal liver function (ALT maximum value of 181 U/L, AST maximum value of 158 U/L). The liver function index of Group B was significantly higher than that of Group A, and the difference was statistically significant (P < 0.05), suggesting that severe patients are more likely to have liver dysfunction. Most patients had normal renal function, and only 2 (2.9%) had abnormal renal function indicators, both of whom were severe patients, considering that SARS-CoV-2 may not cause significant kidney damage. 36 (52.2%) patients were associated with hypoproteinemia, and serum albumin (ALB) in Group B was significantly lower than that in Group A, considering that the function of synthetic ALB was decreased caused by liver function damage in severe patients. In addition, the basal metabolic rate and resting energy consumption of severe patients were high, and the ALB catabolic metabolism was accelerated. Therefore, attention should be paid for severe patients to the treatment of albumin supplementation. FIB is a coagulation factor mainly secreted into the blood by the liver cells. It is involved in the blood coagulation process and is a key factor in thrombosis. In addition, FIB is also a stress response protein FIB. A total of 45 (65.2%) patients had elevated blood FIB content, considering that SARS-CoV-2 infection would lead to stress response of the body, promote the synthesis and release of FIB by liver cells and macrophages, and thereby increase serum. In addition, FIB in Group B was significantly higher than that in Group A, with statistically significant difference (P༜0.05). It is considered to be caused by systemic inflammation which was relatively obvious in severe patients. D-dimer is a product of fibrinolytic cross-linked fibrin clot formation. Elevated D-dimer levels indicate high blood clotting and are a sensitive marker of acute thrombosis. This study shows that the value of D-dimer in Group B was significantly higher than that in Group A, with statistically significant difference (P༜0.05). It is considered that harmful substances such as viruses and endotoxins can activate coagulation factor XII after entering the blood, activate the endogenous coagulation system, and activate the fibrinolytic system, which leads to an increase in D-dimer. Severe patients often have systemic inflammation, which could cause endothelial function to be impaired, resulting in platelet aggregation, release of coagulation factors, thereby leading to hyperfunction of the fibrinolytic system. The increase of FIB and D-dimer indicates that preventive anticoagulation therapy should be given to COVID-19 pneumonia patients, especially for severe patients.
Treatment results indicate that 61 (88.4%) patients were treated with oxygen therapy, among which nasal catheter oxygen was the main treatment (43 (84.3%) cases in Group A, 5 (27.8%) cases in Group B). Some patients in Group B were associated with respiratory failure, thus non-invasive ventilator assisted ventilation or high-flow oxygen were needed, and the difference was statistically significant (P༜0.05). The vast majority (97.1%) of patients received antiviral treatment immediately after admission, while only 22 (31.9%) patients were treated with hormone therapy, most of whom were from Group B, also the time of hormone use was significantly longer than that of Group A, and the difference was statistically significant (P༜0.05).
In this study, L, MB and FIB were selected as meaningful laboratory indicators to help distinguish between general and severe classification. The results showed that the values of L, MB, and FIB in the Group B were significantly different from those in the Group A, and the difference was statistically significant (P༜0.05). When FIB takes a critical value of 4.805 g/L, the sensitivity and specificity are 100% and 14%, respectively, which are significantly better than L and MB. It can be seen from the ROC chart that FIB has the largest area under the ROC curve (0.974), indicating that FIB could be used as an effective laboratory indicator to help distinguish general and severe classification, but the specificity of FIB is low. Therefore, a comprehensive diagnosis should be made based on clinical manifestations and influence data. For patients with chest tightness, L < 1.071*10^9/L, and FIB significantly higher than 4.9065 g/L, we should be alert to the possibility that they may subsequently progress into severe or severe tendency, which will help timely clinical judgement of the condition and adjustment of treatment.
Our study has some limitations. This study did not cover all the COVID-19 cases in our hospital; some patients were excluded but were not diagnosed; the number of selected cases was relatively small; there might be bias factors in case selection; findings of statistical tests and p values should be interpreted with caution, and non-significant p values do not necessarily rule out the difference between Group A and Group B patients. In addition, the patient's discomfort symptoms are highly subjective, and there might be errors in clinical symptoms. Some patients did not seek medical treatment in time, and the imaging performance was lagging. Therefore, further researches are needed to get a full picture of the COVID-19 pneumonia.