| Objective:To investigate the serological characteristics of rheumatoid arthritis-associated interstitial lung disease(RA-ILD)and the clinical application value of KL-6 in RA-ILD.Methods:Retrospective analysis of general information,serological indicators of RA-ILD patients in our hospital from 2018 to 2021.137 rheumatoid arthritis patients were enrolled,57 patients were RA-ILD study group,and 80 patients were RA-non-ILD control group,30 healthy persons were taken as the healthy control group.57 RA-ILD patients were divided into 29 patients early RA-ILD and 28 patients non-early RA-ILD according whether the disease duration was greater than 2 years.The 80 RA-non-ILD patients were divided into 31 patients early RA-non-ILD and 49 patients non-early RA-non-ILD according whether the disease duration was greater than 2 years.Through the comparison of general data and laboratory indicators between different groups:including gender,age,krebs vonden Lungen-6,anti-CCP antibody,rheumatoid factor,lactate dehydrogenase,erythrocyte sedimentation rate,C-reactive protein,serum amylase A,immunoglobulin G,immunoglobulin M,immunoglobulin A,complement 3,complement 4 and the clinical application value of KL-6 in RA-ILD were studied and analyzed.Results:(1)The age of RA:RA-ILD group:60.40±14.81 years old compared with RA-non-ILD group:50.72±11.98 years old,P=0.000<0.05;early RA-ILD:66.82±12.73 years old respectively compared with non-early RA-ILD group:53.75±14.03 years old and early RA-non-ILD group:54.15±10.92 years old,P<0.05,there were statistical differences;(2)KL-6:RA-ILD:469.00(306.50,1113.00)U/ml compared with RA-non-ILD:202.00(145.30,313.30)U/ml and healthy control group of 190.00(149.30,285.00)U/ml,P<0.05,there were statistical differences;RA-non-ILD compared with the healthy control group,P>0.05,there was no statistical difference;(3)The respiratory symptoms in early RA-ILD group:22/29(75.86%)compared with non-early RA-ILD group:13/28(46.43%),χ2=5.207,P<0.05;Comparison of KL-6 in RA-ILD with respiratory symptoms and RA-ILD without respiratory symptoms:531.00(311.50,1126.00)vs.431.00(262.00,830.50)U/ml,Z=2.541,P=0.011<0.05,there was a statistical difference;(4)The anti-CCP antibody,RF,C-reactive protein,erythrocyte sedimentation rate,serum amylase A,immunoglobulin Protein IgG,IgA,IgM were not statistical difference in RA-ILD between RA-non-ILD,P>0.05;(5)The comparison of Lactate dehydrogenase between RA-ILD group and RA-non-ILD group:218.00(187.50,262.00))vs.194.50(166.50,211.50)U/L,P=0.001<0.05;early RA-ILD group and early RA-non-ILD group:222.00(195.00,271.00)vs.180.00(161.00,208.00)U/L,P=0.000<0.05;The correlation between KL-6 and LDH:r=0.457,P=0.000<0.05;(6)The comparison of complement 3 between RA-ILD group and RA-non-ILD group:1.10±0.22 vs.1.26±0.24g/L,P=0.000<0.05.The comparison of complement 4 between RA-ILD group and RA-non-ILD group:0.27±0.09vs.0.30±0.10g/L,P=0.034<0.05;(7)The AUC of KL-6 in RA-ILD:0.831,the sensitivity:0.681,the specificity:0.846,the best diagnostic concentration:342.5U/ml;the AUC of KL-6 combined with anti-CCP antibody and RF was 0.847,the sensitivity:0.766,specificity:0.821;(8)The concentration change of KL-6 was positively correlated with the progression of the disease,the correlation coefficient was 0.693,P=0.000<0.05;(9)Risk model analysis:old age(>60 years old)(OR=4.125,95%CI:1.580-10.766,P=0.004<0.05),KL-6 positive(OR=17.016,95%CI:5.054～57.292,P=0.000<0.05)are risk factors for RA-ILD.Conclusions:(1)There was no significant difference in inflammatory indexes between the RA-ILD group and the RA-non-ILD group;(2)KL-6 in RA-ILD group was significantly higher than RA-non-ILD group,KL-6 can be used as an auxiliary diagnosis for RA-ILD;(3)The concentration change of KL-6 was positively correlated with disease progression;(4)Old age(>60 years old)and KL-6>435 U/ml are risk factors for RA-ILD. |
