Effect Of Mycoplasma Pneumoniae Infection On Kawasaki Disease And Related Risk Factors

Background Kawasaki disease(KD)is an acute systemic vasculitis,which mostly occurs in children younger than 5 years old.It mainly involves small and medium-sized arteries,including coronary arteries.The most serious complication is coronary artery aneurysm.The incidence of KD is increasing with years and has become the main cause of children's acquired heart disease in developed countries.Existing evidence showed KD is associated with dozens of microorganisms,and mycoplasma pneumoniae(MP)is an important pathogen.In addition to lung invasion,MP can also cause extrapulmonary involvement.Many studies on KD complicated with MP infection suggested that MP is the pathogen of KD.However,the clinical characteristics of KD complicated with MP infection are still not clear,and the mechanism of MP infection leading to the occurrence of KD and coronary artery lesions has not been clarified.Objective Analyse the effect of MP infection on KD,and seek the risk factors of intravenous immunoglobulin(IVIG)resistance of KD complicated with MP and MP infection complicated with incomplete KD,so as to guide clinical diagnosis and treatment.Methods We retrospectively analysed 506 pediatric patients with KD hospitalized in our hospital from January 1,2013 to March 1,2018,including 200 cases in the KD complicated with MP group and 306 cases in the KD non-complicated with MP group.1.We used the propensity score matching method to 1:1 adjust the age,gender,incomplete KD,glucocorticoid use,IVIG use time,IVIG use method and initial aspirin dose of the two groups.The duration of fever,length of hospital stay,coronary artery diameter,incidence of coronary artery dilation,incidence of coronary artery aneurysm and incidence of IVIG resistance were compared between the two groups.2.On the basis of the above database,the KD complicated with MP group was divided into two groups according to whether reacting to IVIG or not.We first compared the clinical data of the two groups by single factor,and then binary logistic regression was conducted to obtain the independent risk factors for IVIG resistance in KD complicated with MP infection.We drew the receiver operating characteristic(ROC)curve and select the optimal cut-off value.3.We retrospectively analysed 68 cases of MP infection complicated with incomplete KD in pediatric inpatients of our hospital from January 1,2015 to December 31,2018 as the case group.A total of 136 cases of pediatric wards with MP infection without KD in the same period were selected as the control group.The clinical data of the two groups were compared by single factor,and then binary logistic regression was performed to obtain independent risk factors of MP infection complicated with incomplete KD.We drew the ROC curve and selected the best cut-off value.Results 1.After 1:1 pairage using the propensity analysis matching method,it was found that the duration of fever was longer in the KD complicated with MP group,the coronary artery diameter was larger,and the incidence of coronary artery aneurysm was higher,the difference was statistically significant(P<0.05).The incidence of IVIG resistance was higher in the KD complicated with MP group,but the difference was not statistically significant(P>0.05).2.Compared with the IVIG non-resistance group,the incidence of sepsis,white blood cell count,neutrophil percentage,neutrophil count,neutrophil/lymphocyte count,CRP and erythrocyte sedimentation rate were higher and the hemoglobin,hematocrit,albumin,creatine kinase isozyme were lower in the IVIG resistance group.There were statistically significant differences between the two groups in the proportion of time to apply IVIG and glucocorticoid usage(P<0.1).Logistic regression analysis showed that increased CRP,application of IVIG before the 5th day or after the 10th day of the course of disease and combined sepsis were independent risk factors for KD complicated with MP with IVIG resistance(P<0.05).The area under CRP curve was0.669,the optimal cut-off value was 82.66mg/L,and the sensitivity and specificity were 65.4%and 64.9%,respectively.3.Compared with control group,temperature(>39?),duration of fever>5 days,duration of fever>7 days,duration of fever>10 days,the proportion of mixed EB virus infection,mixed herpes simplex virus infection and mixed two or more pathogens infection was higher.Age,white blood cell count,neutrophil percentage,neutrophil count,platelet count,CRP,erythrocyte sedimentation rate,alanine aminotransferase,?-glutamyl transferase and total bilirubin level were higher,neutrophil/lymphocyte,hemoglobin,total cholesterol and albumin levels were lower,the difference was statistically significant(P<0.1).Logistic regression analysis showed that duration of fever>5 days,mixed infection with more than 2 pathogens,decreased hemoglobin and albumin and increased platelet count were independent risk factors for MP infection complicated with incomplete KD.The area under the hemoglobin curve was 0.869,the optimal cut-off value was 112g/L,and the sensitivity and specificity were 68.6%and 94.1%,respectively.The area under the platelet curve was 0.840,the optimal cut-off value was 408×10~9/L,and the sensitivity and specificity were 73.5%and 86.0%,respectively.The area under the albumin curve was 0.830,the optimal cut-off value was 40.6g/L,and the sensitivity and specificity were 75.7%and 79.4%,respectively.Conclusion 1.KD complicated with MP infection had a longer inflammatory duration,greater damage to coronary arteries,and it migth be more prone to IVIG resistance.2.Increased CRP,application of IVIG before the 5th day or after the 10th day of the course of disease and combined sepsis were independent risk factors for IVIG resistance in KD complicated with MP infection.3.The duration of fever>5 days,mixed infection with 2 or more pathogens,decreased hemoglobin and albumin and increased platelet count were independent risk factors for MP infection complicated with incomplete KD.