Comparative Analysis Of Connective Tissue Disease-associated Interstitial Lung Disease And Interstitial Pneumonia With Autoimmune Features

Objective This retrospective clinical study aimed to examine the similarities and differences between connective tissue disease-associated interstitial lung disease(CTD-ILD)and interstitial pneumonia with autoimmune features(IPAF)and to identify the influencing factors of CTD-ILD,with a goal of early detection and active treatment of the disease.Methods We conducted a retrospective study of 480 patients: 412 with CTD-ILD and 68 with IPAF.Demographic features,clinical characteristics,laboratory indicators and chest high-resolution computed tomography(HRCT)imaging data were analysed.Results Compared with the IPAF group,the CTD-ILD group contained more women,and the incidences of joint pain,dry mouth/dry eyes and Raynaud's phenomenon were higher;erythrocyte sedimentation rate(ESR) and D-dimer levels were higher;red blood cell(RBC)and hemoglobin(Hb)levels were lower;a high rheumatoid factor(RF)titer(>2 times the normal upper limit)was observed,and anti-cyclic citrullinated peptide antibody(anti-CCP),anti-keratin antibody(AKA),antinuclear antibody(ANA)and anti-melanoma differentiation-associated gene 5 antibody(anti-MDA5)levels were higher.Compared with CTD-ILD patients,IPAF patients were more likely to present initially with respiratory symptoms,with higher rates of fever,cough and expectoration,dyspnea and Velcro crackles;anti-Ro52 titers were higher;Incidences of honeycombing opacity,reticulate opacity,patchy opacity and pleural thickening were greater.Female sex,a high RF titer(>2 times the normal upper limit),anti-CCP positivity,ANA positivity and anti-MDA5 positivity were risk factors for CTD-ILD when the odds ratios were adjusted.Conclusion CTD-ILD and IPAF patients differed in demographic features,clinical characteristics,laboratory indicators and chest HRCT imaging data.Female sex,a high RF titer(>2 times the normal upper limit),anti-CCP positivity,ANA positivity and anti-MDA5 positivity were risk factors for CTD-ILD.