The Predictive Value Of Neutrophil-lymphocyte Ratio And Platelet-lymphocyte Ratio In Dermatomyositis/Polymyositis With Interstitial Lung Disease

BackgroundDermatomyositis(DM)/ polymyositis(PM)is a chronic autoimmune connective tissue disease.Muscle inflammation is the defining feature of the disease,leading to proximal muscle weakness and disability,abnormal skin lesions,ulceration,calcinosis,and malignancy.Interstitial lung disease(ILD)is a common complication of DM/PM and it is a known contributor to increase morbidity and mortality of the patients.The quality of life for DM/PM patients is poor;thus early diagnosis and therapy of the disease is beneficial for the patient’s long-term outcome.Recently,the neutrophil-lymphocyte ratio(NLR)and platelet-lymphocyte ratio(PLR)have emerged as useful biomarkers to predict systemic inflammation.Therefore,many studies have shown that NLR as well as PLR,another parameter derived from a routine complete blood count(CBC),are positively associated with inflammation,many cancers,cardiovascular disease,and diabetic nephropathy.However,there is few studies to investigate the relationship between the biomarkers and DM/PM.ObjectiveTo investigate and compare the predictive value of NLR and PLR for ILD in DM/PM patients and their relationship with the clinical characteristics.MethodsSeventy-three newly diagnosed patients with DM/PM and 147 healthy subjects were selected in this retrospective study.All of them were collected from the Second Affiliated Hospital of Nanchang University between January 2011 and May 2016.We divided the 73 DM/PM patients into two groups: 55 without ILD and 18 with ILD.Complete clinical characteristics were extracted from the medical records of DM/PM patients.The correlations between NLR,PLR and the clinical characteristics were analyzed.Results1.There were 18 DM/PM with ILD among 73 DM/PM patients and the incidence of ILD was 24.7%.There was no difference for age or gender among DM/PM patients with or without ILD(P> 0.05).2.The NLR and PLR were significantly higher in DM/PM patients than those in the control group(both P< 0.001).For DM/PM patients with ILD,the NLR and PLR were higher than those in DM/PM patients without ILD(P = 0.004 and P = 0.026,respectively).3.The NLR was positively correlated with C-reactive protein(CRP)(r = 0.543,P< 0.001),the erythrocyte sedimentation rate(ESR)(r = 0.513,P = 0.001)and lactate dehydrogenase(LDH)(r = 0.254,P = 0.030).PLR was positively correlated with creatine kinase(CK)(r = 0.306,P = 0.008).4.NLR is an independent predictor for DM/PM patients with ILD(EXP(B)= 1.594,95% CI(1.138-2.233),P = 0.007).5.Based on the ROC curve,to predict DM/PM patients with ILD,the best cut-off value of the NLR was 3.98(sensitivity 88.9%,specificity 52.7%,AUC = 0.727),and the best cutoff value of PLR was 221.69(sensitivity 77.8%,specificity 69.1%,AUC = 0.722).