Analysis Of Clinical Characteristics Of Connective Tissue Diseases With Interstitial Lung Disease As The Main Manifestation

Objective: To analyze the clinical features of CTD-ILD patients with ILD as the main manifestation in order to better understand this type of disease and provide a clinical reference for early diagnosis and treatment.Methods: A retrospective study was conducted to collect the clinical data of patients finally diagnosed with CTD-ILD who were hospitalized in the Department of Respiratory Medicine of the Second Hospital of Lanzhou University from January2020 to September 2022 according to the inclusion criteria,and the ILD-GAP index score was calculated and divided into stages I-IV.In this study,because there were few patients with stages III and IV,they were combined with stage II patients as the high mortality group and stage I as the low mortality group.The differences in the general data,clinical manifestations,laboratory tests and chest CT between the two groups were compared to investigate the clinical characteristics of CTD-ILD patients with ILD as the main manifestation.Results: Ninety-five patients with CTD-ILD were finally included and divided into low mortality group(n = 57)and high mortality group(n = 38)according to the ILD-GAP score.1.General data: 95 patients,the average age of onset was 59.44 ±12.21 years,mainly female,the male to female ratio was 1:1.43;the composition of primary CTD disease was as follows: SS24 cases(25.3%),RA14 cases(14.7%),IPAF14 cases(14.7%),AV12 cases(12.6%),IIM 11 cases(11.6%,including ASS3 cases,DM/PM 6 cases,CADM 2 cases),SLE7 cases(7.4%),OS6 cases(6.3%),SSc4 cases(4.2%),MCTD3 cases(3.2%).Among them,CTD-ILD patients in the high mortality group were older(P < 0.05)and had a higher proportion of smoking(P < 0.01)than those in the low mortality group,and the difference was statistically significant;BMI,gender,presence of diabetes and hypertension were not significantly different between the two groups(P > 0.05).2.Clinical manifestations: Of the 95 patients,83(87.4%)had chest tightness/shortness of breath,79(83.2%)had cough and expectoration,43(45.3%)had dry mouth/dry eyes,39(41.1%)had muscle and joint discomfort,35(36.8%)had Velcro rales,23(24.2%)had cyanosis,20(22.1)had fever,16(16.8%)had fatigue,13(13.7%)had the rash,7(7.4%)had technician hands,7(7.4%)had morning stiffness,6(6.3%)had Raynaud’s phenomenon,4(4.2%)had clubbing finger,and 2(2.1%)had photosensitivity.Comparison between the two groups showed that Velcro rales and cyanosis occurred more frequently in the high mortality group,with a significant difference between the two groups(P < 0.05),while other clinical manifestations were not significantly statistically different.3.Laboratory tests: Crea,UA,ALT,LDH,NLR,LAR,ESR,and D-Dimer levels were higher and ALB was lower in the high mortality group,and the difference was statistically significant(P <0.05);correlation analysis revealed that Crea,UA,ALT,LDH,NLR,LAR,ESR,DDimer and PASP were positively correlated with ILD-GAP stage,while ALB was negatively correlated with ILD-GAP stage;comparative analysis of the predictive value of ALB,LDH,and LAR for mortality was performed,ROC curve was drawn,and the area under the curve,sensitivity,specificity,optimal threshold,Youden index and 95% CI were calculated,and the results were as follows: ALB: 0.626,66.7%,63.2%,36.80 g/L,0.298,0.255 ～ 0.493.LDH: 0.685,65.8%,68.4%,256.00 U/L,0.342,0.579 ～ 0.791.LAR: 0.702,71.1%,66.7%,6.69,0.377,0.594 ～ 0.810.4.Autoantibody analysis: Among all antibody expressions,the positive rate of ANA antibody was the highest(83.0%),and it was common in all types of CTD-ILD;antiANCA antibody,anti-n RNP antibody,anti-Sm antibody,anti-Ro-52 antibody,anti-SSA/SS-B antibody,anti-Sd-70 antibody,anti-Jo-1 antibody,RF and anti-CCP antibody were all CTD-related antibodies,except SS-B antibody,the other antibodies were statistically different between all types of CTD disease groups(P < 0.05);while dsDNA antibody was not positive in the diseases in this study.The antibody expression results between the high mortality group and the low mortality group were analyzed,and the results suggested that there were no statistically significant differences in autoantibodies between the two groups(P > 0.05).Chest CT analysis: Of the 95 patients,50(52.6%)had grid shadows on chest CT,followed by 48(50.5%)with mediastinal lymphadenopathy,42(44.2%)with pleural thickening,36(37.9%)with ground-glass opacities,34(35.8%)with nodular shadows,32(33.7%)with cord-like shadows,24(25.3%)with patchy shadows,17(17.9%)with honeycomb lung,11(11.6%)with pleural effusion,and 3(3.2%)with air bronchogram.Among them,honeycomb lung was more common in the high mortality group(P < 0.05),while other imaging findings were not significantly statistically different between the two groups(P > 0.05).Of the 95 patients,54 had pulmonary infection and 48 had pulmonary hypertension,of which 30(78.9%)had pulmonary infection in the high mortality group and 24(42.1%)had pulmonary infection in the low mortality group,and the incidence of pulmonary infection was higher in the high mortality group,with a statistically significant difference between the two groups(P < 0.05);the median pulmonary arterial systolic pressure was 43.26(27.47,56.31)mm Hg in the high mortality group and 27(71.1%)in the low mortality group,the median pulmonary arterial systolic pressure was 28.61(24.89,40.05)mm Hg in the low mortality group and 21(36.8%)in the high mortality group,and the incidence of pulmonary hypertension was higher in the high mortality group,with a significant difference between the two groups(P < 0.05).7.Multivariate analysis: Older age,elevated LAR ratio,pulmonary infection and honeycomb lung were independent risk factors of high mortality in CTD-ILD by multiple logistic regression analysis(P < 0.05).Conclusion: 1.CTD-ILD patients with ILD as the main manifestation are mainly middle-aged women in the population,advanced age and smoking are highrisk factors for high mortality,and the clinical manifestations are mainly chest tightness/shortness of breath,cough/sputum,and lack specificity,but patients in the high mortality group show more significant cyanosis and Velcro rales in the early stage,and hypoxia is more severe.2.UIP is the main imaging type of CTD-ILD patients with ILD as the main manifestation,and the early imaging findings are mainly grid sign,and the presence of honeycomb lung indicates a poor prognosis.3.Crea,UA,ALT,ALB,LDH,NLR,LAR,ESR,and D-dimer levels are correlated with the prognosis of CTD-ILD patients,and LAR is of higher prognostic value than LDH and ALB alone.4.Autoantibody levels are instructive for the diagnosis of the primary disease of CTD-ILD,but the relationship with prognosis cannot be determined.ANA antibodies are highly positive in CTD patients with ILD as the main manifestation,and screening can be performed for ILD suspected to be caused by CTD.5.Advanced age,elevated LAR ratio,combined pulmonary infection,and honeycomb lung are independent risk factors for high mortality in CTD-ILD.