A Single-center Retrospective Study Of Tibetan Rheumatoid Arthritis Complicated With Interstitial Lung Disease In Tibet

Objective:In this paper,we collected the general,laboratory and imaging data of patients with rheumatoid arthritis(RA)combined with interstitial lung disease(ILD)and patients with rheumatoid arthritis without interstitial lung disease in Tibet,and analyzed the risk factors for RA combined with ILD and the pulmonary CT imaging characteristics of such patients.Method:A retrospective analysis was made of 245 patients with rheumatoid arthritis in Tibet who were admitted to the rheumatology and Immunology Department of the people’s Hospital of Tibet Autonomous Region from January 2018 to June 2019.According to the results of HRCT,they were divided into RA with ILD group and RA without ILD group.The general data of the two groups were collected,including gender,age,duration of disease,smoking history;clinical manifestations,including respiratory system performance,morning stiffness of joints,number of joint tenderness,number of joint swelling;history of methotrexate and leflunomide;laboratory test indicators,including hemoglobin,ESR,CRP,rheumatoid factor,anti keratin antibody,anti cyclic citrullinated peptide antibody,lactate dehydrogenase,immunoglobulin(Ig A,Ig G,Ig M),etc,were compared whether there is statistical significance between the two groups.Result:Among the 245 Tibetan RA patients,46(46 / 245,18.8%)were RA patients with ILD,and 199(199 / 245,81.2%)were RA patients without ILD.There were significant differences in the mean age(50.30 ± 10.62 vs 46.44 ± 10.97 years,P < 0.05),mean course of disease(8.35 ± 6.35 vs 4.94 ± 3.89 years,P < 0.05)and smoking rate(13.0% vs 3.5%,P < 0.05)between the two groups.Although the male ratio of ra-ild group was higher than that of RA without ILD group(17.4% vs 9.5%,P > 0.05),the difference was not statistically significant.The morning stiffness time(2.35±4.39vs4.48±11.41 hours,P > 0.05),the number of joint swelling(5.74 ± 2.86 vs 5.92 ± 3.05,P > 0.05),and the number of joint tenderness(12.87 ± 3.75 vs 12.86 ± 5.28,P > 0.05)of patients in the RA combined ILD group and the RA not combined ILD group showed no statistically significant difference.The proportion of respiratory system performance in the RA combined with ILD group was significantly higher than that in the RA without ILD group(41.3% vs 19.6%,P < 0.05),and the difference was statistically significant.There was no statistically significant difference in the proportion of patients using leflunomide(56.5% vs 58.8%,P > 0.05)and methotrexate(17.4% vs 22.1%,P > 0.05)between RA combined ILD group and RA not combined ILD group.The RF[255.9(140.0)vs123.6(153.9)IU/ml,P <0.05],anti-ccp antibody levels [167.91(291.93)vs89.46(121.67)RU/ml,P<0.05] and AKA positive rates(58.7% vs 41.7%,P <0.05)of the RA with ILD group and the RA without ILD group were statistically significant.In the RA with ILD group and RA without the ILD group,Hb(143.60 ± 17.26 vs 141.30 ± 21.92 g/L,P > 0.05),ESR increased(63.0% vs 61.8%,P > 0.05),CRP[20.23(29.39)vs19.34(22.78)mg/L,P>0.05],LDH(203.36 ± 63.26 vs 184.78 ± 51.92 U/L,P > 0.05),immunological indexes Ig A(3.13 ± 1.14 vs 3.33 ± 1.29 U/L,P > 0.05),Ig G(14.98 ± 3.68 vs 15.85 ± 3.42 U/L,P > 0.05)and Ig M(2.05 ± 0.77 vs1.84±0.80U/L,P > 0.05)showed no significant difference.Multivariate Logistic regression analysis was performed based on whether the ILD was combined as the dependent variable.The results showed that long course of disease,high titer RF and high titer anti-CCP antibody were independent risk factors for the RA related ILD in Tibetan Tibetan people in Tibet in this study.In the chest CT findings of 46 Tibetan patients with RA combined with ILD,mesh shadow,ground glass shadow and honeycomb shadow were more common,followed by patch infiltration or consolidation shadow,and nodules shadow was rare.Interstitial lung disease(UIP)was the most common type,followed by NSIP,in 46 Tibetan patients with RA and ILD.Conclusion: 1.There were differences in age,course of disease,smoking history,RF,anti-CCP antibody and AKA between RA with ILD group and RA without ILD group.2.Long course of disease,high titer of RF and high titer of anti-CCP antibody are independent risk factors of Tibetan RA-ILD in Tibet.3.Tibetan patients with long course of disease,high titer of RF and high titer of anti-CCP antibody should improve pulmonary CT examination early.