Analysis Of Clinical And Epidemiological Characteristics Of COVID-19 In Linyi City

Background and Objective:Coronavirus disease 2019(COVID-19),referred to as "novel coronavirus pneumonia",the WHO named it "COVID9"on February 11,2020.Since December 2019,many countries around the world have reported cases of COVID-19,and WHO believes that the current COVID-19 outbreak can be called a global pandemic.Cases in China were first discovered in some hospitals in Wuhan,Hubei Province,and most of the cases had a exposure history of the South China seafood market.On January 21,2020,Shandong province reported the first COVID-19 confirmed cases,two days later,Linyi City reported its first COVID-19 case.64 cases have been reported in Linyi City,including 49 confirmed cases and 15 asymptomatic infections as of February 17.As one of the ten COVID-19-designated hospitals in Shandong Province,Linyi People’s Hospital admitted 41 patients.This study collects the epidemiological information of 64 cases and the clinical information of 41 cases,aims to analyze the epidemiological characteristics of COVID-19 in Linyi City,and compare the clinical characteristics and post-discharge conditions of mild and severe patients.Explore the relationship between the dynamic changes of peripheral blood lymphocyte count and patient survival based on the joint model,To provide a reference for the survival research of patients with coronavirus disease.Methods:Collect the epidemiological information of the new coronavirus pneumonia cases reported in Linyi from January 21 to February 17,2020,and analyze the epidemiological characteristics.To retrospectively analyze the clinical diagnosis and treatment data of 41 patients with novel coronavirus pneumonia admitted to Linyi People’s Hospital from January 21 to February 17,2020,analyze clinical characteristics,treatment process,nucleic acid test results,and post-discharge conditions,using group Methods such as t-test,Fisher’s exact probability method,and non-parametric test have relatively mild and severe differences.Use R 4.0.2 software JM package to establish a joint model of longitudinal data model and survival data model.Results:1.The new coronavirus pneumonia epidemic in Linyi City has the following epidemiological characteristics:①The evolution of the epidemic over time can be divided into three stages:The first stage:January 23-30,which is the early stage of the epidemic(10 cases),mainly imported cases(8 cases).The second stage:January 31st to February 13th,is the high epidemic period(28 cases),mainly imported cases and local cases coexist.The third stage:February 14-17,a period of steady decline,a total of 2 cases were reported.②The new coronary pneumonia has obvious clustering characteristics:the number of cases involved in a typical cluster epidemic accounts for 75%of the reported cases in Linyi City.③Calculate the longest incubation period of patients with new coronary pneumonia in Linyi City is 18 days,the shortest incubation period is 2 days,and the median time is 7 days.Patients who live temporarily in Hubei take the median residence time as the infection time,so the incubation period is an estimate.2.Among the 41 patients,34 cases were mild(82.93%)and 7 cases were severe(17.07%);fever,cough,and chest tightness were common symptoms of patients with new coronary pneumonia,and the proportions of them in 41 patients were 68.29%.78.0%,24.39%;the proportion of mild cases with underlying diseases was 29.41%,and the proportion of severe cases with basic diseases was 85.71%,the difference was statistically significant(P=0.003);the average age of mild patients in the study was 42.43±16.77 years,The average age of critically ill patients was 58.57±17.63 years old,and the difference was statistically significant(t=3.077,P=0.004);light and severe patients had difference in lymphocyte count,neutrophil count,lactate dehydrogenase,procalcitonin,and red blood cell,and the difference in sedimentation rate was statistically significant.The statistics and P values were lymphocyte count(t=6.054,P<0.001),neutrophil count(Z=2.114,P=0.034),lactate dehydrogenase(t=-4.223,P<0.001),procalcitonin(Z=3.145,P=0.001),erythrocyte sedimentation rate(Z=2.748,P=0.004);the median time for mild nucleic acid to become negative is 13(10-15)Days,16(14-19)days for severe illness,the difference was statistically significant(Z=3.034,P<0.001).The use of antibiotics,antifungal drugs,hormones,immune system enhancers,and oxygen therapy in severely ill patients is higher than that in mild patients.3.There was a phenomenon of "fuyang" in discharged patients(9 cases),and the proportion of "fuyang" was 21.95%.The types of fuyang specimens included 8 cases of stool and 1 case of throat swab;the shortest period from negative nucleic acid to recovery of positive was 8 days,the longest was 22 days,and the median time was 11(9-14)days;the shortest from discharge to second admission was 3 days,the longest was 14 days,and the median time was 7(6～8.5)days.4.The length of time,clinical severity,and oxygen inhalation have a significant impact on the survival of patients with new coronary pneumonia.Oxygen inhalation and procalcitonin have a greater contribution to the lymphocyte count.A decrease in log(lymphocyte)unit corresponds to an increase of exp(-α)=0.1486 times the survival risk.Conclusion:1.The development of the new crown pneumonia epidemic in Linyi City presents three stages:the early stage of the epidemic,the high-incidence period,and the steady decline period,and the characteristics of clustering was obvious.In the early stage,imported cases were mainly cases.The high-incidence period was the coexistence of imported cases and local cases.As people’s awareness of new coronary pneumonia continued to increase,and effective prevention and control measures were actively adopted,the epidemic soon entered a period of steady decline.2.The main clinical symptoms of new coronary pneumonia are fever,cough,and chest tightness.Old age and basic diseases are easy to develop into severe disease.The lymphocyte count of severe patients is significantly lower than that of mild patients,lactate dehydrogenase,procalcitonin,and red blood cell sedimentation.The rate and neutrophil count were significantly higher than those of mild patients.3.Due to the phenomenon of "fuyang",the management of discharged patients needs to be strengthened.Perform a stool nucleic acid test before leaving the hospital,and only after it is negative can be discharged,which can reduce the possible risk of gastrointestinal transmission.Properly extending the time of centralized isolation may reduce the spread of the virus.4.The results of the joint model suggest that in the process of clinical diagnosis and treatment,it is necessary to pay close attention to the dynamic changes of lymphocyte count and actively take intervention measures to reduce the occurrence of severe cases.Shortcomings of the research:Shortcomings of the research:The sample size of this study is small and cannot objectively reflect the reliability of the data and the credibility of the results.The longitudinal sub-model in the joint model uses a linear mixed effects model,and no comparative analysis of other models.The survival sub-model only uses the Cox proportional hazard model to build the model,It does not use exponential distribution and Weibull distribution modeling,and lacks comparative analysis.In the future work,can try to build other models and compare the models.