A Retrospective Case-control Study On Dermatomyositis With Interstitial Lung Disease

Objective:A retrospective case-control study was conducted by investigating the differences of clinical characteristic between in-patients of dermatomyositis(DM)with and without interstitial lung disease(ILD)during the 14-year-duration in order to deepen the acknowledgement of ILD associated with DM,and improve the diagnostic and therapeutic quality.Methods:Medical records of patients hospitalized for DM in the 2nd Affiliated Hospital of Kunming Medical University from January 2002 to December 2016 were reviewed.Cases were divided into two groups by with ILD or not accordingly.General information,first-onset symptom,main symptom and sign,main laboratory and autoantibodies tests result,imaging data,skin and muscle biopsy result,bacterial/fungal infections characteristics,treatment plans were collected.The single-factor differences between the two groups were compared by statistical methods such as t test,Mann-Whitney U test and chi-square test.And Logistic regression analysis was conducted to discover risk or protective factors.Results:A total of 107 cases were enrolled in the study,of which 80 females(74.8%)and 27 males(25.5%)with a female to male ratio of 2.96:1.While 66 cases(61.7%)were non-ILD and 41 cases(38.3%)were with ILD.The average onset age of ILD group was 49.83±11.45,which was higher than the non-ILD group of 41.85± 18.52(P<0.05),however regression analysis failed to prove that the higher onset age was a risk factor of ILD.The incidence of bacterial/fungal infection rate in ILD group was 75.6%and the concurrent infection rate was 39%,which was significantly higher than the non-ILD group,whose number was 24.2%and 6.1%(P<0.05).62.1%patients in non-ILD group were prescribed glucocorticoid(GC)alone,31.8%patients were prescribed GC combined with immunosuppressants,while only 41.5%patients in ILD group were prescribed GC alone and 56.1%patients were prescribed GC combined with immunosuppressants.Male patients(OR=9.01,95%CI:1.652-49.143),elevated ESR levels(OR=1.048,95%CI:1.008-1.090)and serum ferritin levels(OR=1.007,95%CI:1.001-1.014)were risk factors of DM-ILD.Conclusions:The severity rate of ILD group patients was higher than non-ILD group patients,and required antimicrobial therapy more often because of bacterial/fungal infection.The elevated ESR and serum ferritin were risk factors of DM-ILD.Male patient was also a risk factor of DM-ILD,the probability of ILD in male patients was 9.01 times over female patients.