Prognostic Value Of Biomarkers In Idiopathic Inflammatory Myopathy Associated Interstitial Pneumonia

Objectives: Idiopathic inflammatory myopathies(IIM)is a systemic autoimmune disease,which includes dermatomyositis(DM),polymyositis(PM),inclusion body myositis and immune-mediated necrotizing myositis.PM is characterized by progressive symmetrical proximal muscle weakness,which is called dermatomyositis when skin involvement occurs.Interstitial lung disease(ILD)is a common pulmonary complication of IIM,which is related to the deterioration of prognosis and the increase of mortality.Recently,some researchers found that neutrophil-to-lymphocyte ratio(NLR),platelet-lymphocyte ratio(PLR),monocyte-lymphocyte ratio(MLR)and C-reactive protein-to-albumin ratio(CAR)played an important role in the progression of IIM.However,there are few studies to investigate the relationship between the biomarkers and the prognosis of idiopathic inflammatory myopathies associated interstitial lung disease(IIM-ILD).Therefore,in this research,we studied NLR,PLR,MLR and CAR values and determined their effect on prognosis.Methods: A total of 117 patients who were diagnosed with IIM-ILD between January2017 and August 2019 at the Anhui Provincial Hospital Affiliated with Anhui Medical University were selected.The classical PM/DM was diagnosed according to the criteria of Bohan and Peter.The presence of ILD was confirmed by typical HRCT findings,which include irregular linear,reticular,or ground-glass opacities,consolidations,traction bronchiectasis,or honeycombing.139 patients without ILD were excluded.112 patients were excluded because of missing baseline data regarding specific antibodies(n = 76),or the presence of malignant tumor(n = 36).The clinical and laboratory results were compared between survivors and non survivors in IIM-ILD patients.All data is anonymous before analysis.The clinical and laboratory characteristics in survivors and non-survivors were compared.The NLR,MLR,PLR and CAR optimal cut-off values of the predicted survival rate were calculated by using the receiver operating characteristic curves(ROC).Cox proportional hazard model was used to assess the factors affecting prognosis.Logistic regression model was used to establish combined diagnosis,and the feasibility of combined diagnosis to evaluate the prognosis of IIM-ILD was explored.Results: Of the 117 patients with IIM-ILD,37 patients(31.62%)died in the follow-up period.There were significant relationships between age,follow-up period,ALC,PLT,ALB,ESR,CRP,NLR,MLR,PLR,CAR,anti-MDA5 antibody and high-dose glucocorticoid and survival(P <0.05).Since NLR,MLR,PLR and CAR were significantly correlated with survival in our patients with IIM-ILD,we performed cut-off optimization for predicting mortality on our study cohort.Optimized cut-offs of each parameter were determined using standard ROC curve analysis.In ROC curve analyses,the areas under the curve(AUC)for non-survivors were 0.686(P =0.001),0.655(P=0.007),0.643(P =0.013),0.671(P =0.003)for NLR,MLR,PLR and CAR respectively.Using ROC curve,optimized cut-offs of NLR(6.898),MLR(0.599),PLR(371.033)and CAR(0.137)for IIM-ILD patients were determined.The sensitivity was 51.4% and specificity was 78.8% for the NLR,56.8% and 80.0% for the MLR,32.4% and 92.5% for the PLR,75.7% and 51.3% for the CAR.Patients were divided into low and high subgroups according to the optimal cut-off values.Patients with high cut-off values presented significantly worse survival compared to that for patients with low values(P <0.05).Multivariate analysis presented that age(HR=1.049,95% CI: 1.015-1.084,P <0.05),high-dose glucocorticoid(HR=1.002,95% CI: 1.001-1.003,P <0.05),hypoproteinemia(HR=0.922,95% CI: 0.855-0.994,P <0.05),anti MDA5 antibody positive(HR=2.576,95% CI: 1.217-5.453,P <0.05)and high MLR(<0.599)(HR=2.134,95% CI: 1.028-4.431,P <0.05)were independent predictors of poor prognosis in patients with IIM-ILD.Logistic regression model was used to establish a joint diagnosis.High MLR,age,hypoproteinemia,anti-MDA5 antibody positive combined with high-dose glucocorticoid(combined predictive indicator)were the highest(0.845)in predicting the prognosis of IIM-ILD,which were higher than the AUC diagnosed separately.The sensitivity was91.67% and specificity was 71.25% for the combined predictive indicator.Conclusions: High,age,hypoproteinemia,anti-MDA5 antibody positive combined with high-dose glucocorticoid can be used to assess the prognosis of the IIM-ILD patients to a certain extent.