The Expression Of Serum KL-6 And Clinical Feature Analysis Of Patients With Rheumatoid Arthritis Related Interstitial Lung Disease

Objective: To investigate the clinical characteristics of rheumatoid arthritis related interstitial lung disease and its correlation with serum KL-6 expression level,so as to improve the early diagnosis of interstitial lung disease associated with rheumatoid arthritis.Methods: 148 patients with rheumatoid arthritis(RA)were enrolled in the Department of respiratory and critical care medicine and rheumatology Immunology Department of General Hospital of Ningxia Medical University in September 2015-2018 January.All patients were examined by CT or HRCT.According to the results of the pulmonary imaging examination,the patients were grouped.87 cases of simple RA group(RA)and 61 cases of interstitial lung disease(RA-ILD)associated with rheumatoid arthritis(RA-ILD).In group RA-ILD,according to the severity of interstitial lung disease,it was further divided into mild interstitial change group(Mild-RA-ILD)group,31 cases and moderate severe interstitial change(Advanced-RA-ILD)group(30 cases).Detailed records of all patients with clinical data(including clinical history,symptoms,physical examination,biochemical test results,autoantibody detection results);while leaving serum were obtained from research objects,ELISA method to detect the serum level of KL-6,compared with pure RA group and in RA-ILD group and RA-ILD subgroups(Mild-RA-ILD and Advanced-RA-ILD)the clinical data and serum KL-6 between group differences.According to the detection results of serum KL-6,we draw the receiver operation(ROC)curve,and draw the best threshold value,sensitivity and specificity of KL-6 for RA-ILD diagnosis based on curve analysis.Result:1.The general comparison of 1.RA and RA-ILD groups:1.1 the basic composition of the data was compared: among the 148 RA patients,87 cases were pure RA,accounting for 14.9%(87/128),and 61 cases in group RA-ILD,accounting for41.2%(61/148).In the simple RA group,there were 13 males,15%(13/87),74 women,85%(74/87)and 1:5.6.In the RA-ILD group,27 cases were male,44.3%(27/61),34 women,55.7%(34/61),and the male and female ratio was 1:1.3.In group RA-ILD,there were 31 cases of group Mild-RA-ILD,including 9 males,22 females and Advanced-RA-ILD30 cases,including18 male and 12 female.1.2 RA group and group RA-ILD were compared with the sex constitution,the course of the RA,the number of joint involvement and the degree of disease activity(DAS28 score):The average age of group RA-ILD and group RA(60.7± 9.8 vs 50.3±12.7)were male(27/34 vs 13/74),RA duration(10 vs 3),DAS28 score(5.9±1.1 vs,5.7±1.4),the difference was statistically significant(P<0.05).2.The autoantibodies in group RA and group RA-ILD and in different subgroups of RA-ILD and other results were compared:The value of RF titer,CRP,LDH,CEA and CA125 in the RA-ILD group was significantly higher than that in the simple RA group,and the difference was statistically significant(P<0.05).Comparison of autoantibodies and other test results in different subgroups of RA-ILD: RA-ILD,Advanced-RA-ILD,LDH,CEA and CA125 in different subgroups were significantly higher than those in Mild-RA-ILD group(P<0.05).3.The comparison of clinical symptoms and pulmonary imaging in groupRA and RA-ILD:In RA-ILD,the number of cough,expectoration,shortness of breath and dry rale was significantly higher than that of group RA,and the difference was statistically significant(P<0.05).The main types and proportion of interstitial changes in RA-ILD were as follows:grid shadow accounted for 63.9%(39/61),ground glass shadow accounted for 57.3%(35/61),interlobular septal thickening accounted for 49.1%(30/61),pleural thickening accounted for47%(29/61),etc.4.The results of serum KL-6 level in group RA and RA-ILD group:The serum KL-6 value of the RA-ILD group was significantly higher than that in the simple RA group(71.3±25.0ng/ml vs 29.2±8.2ng/ml),and the difference was statistically significant(P<0.05).There was no significant difference in serum KL-6 between Mild-RA-ILD and Advanced-RA-ILD(P>0.05).According to KL-6 expression level,ROC curve was drawn.According to ROC curve analysis,the best critical value of KL-6 for RA-ILD diagnosis is41.7ng/ml.The area under the curve is 0.97±0.01,95% confidence interval(0.94,0.99),sensitivity is 92.5%,specificity is 90.9%.5.Multiple factor Logistic regression analysis of RA related interstitial lesions:Taking the interstitial change as the dependent variable,taking age and RA duration as independent variables,Logistic regression analysis was carried out.The results showed that male,advanced age,RA duration and blood LDH level were high risk factors for RA-ILD.Conclusion:1.Rheumatoid arthritis associated interstitial lung disease compared to RA patients,the age of onset,disease duration,DAS28 score,serum CRP,LDH,CEA,CA125 high level;male,age,RA duration and high serum LDH level for rheumatoid arthritis associated interstitial lung the disease risk factors.2.The pulmonary imaging of rheumatoid arthritis related interstitial lung diseases mainly manifested as mesh shadow,glass shadow and thickening of interlobular septum.3.the diagnostic value of serum KL-6 for rheumatoid arthritis related interstitial lung disease is41.7ng/ml,KL-6 is highly sensitive and specific for the diagnosis of interstitial lung disease associated with rheumatoid arthritis.