ILD combined with dermatomyositis(DM) is one of the risk factors for patients' death. Due to the high heterogeneity of the performance and types of DM and ILD, DM-ILD is challenging and needs comprehensive multidisciplinary evaluation [8]. ILD is one of DM's common extra muscular manifestations [9]. Patients with dermatomyositis can take the lung as the target. About 20% − 30% of patients have interstitial lung disease. Patients are usually asymptomatic, but early evaluation is critical. The severity of ILD is not directly related to the severity of DM-related biomarkers, but the presence of DM-ILD is worse than that of DM without ILD patients because ILD is one of the important causes of DM incidence rate and mortality. [10, 11].
Dermatomyositis is a heterogeneous disease that affects women about twice as much as men [12]. The incidence rate of interstitial pneumonia is between 50 and 60 years old. The incidence of males and smokers is slightly higher than [13]. Smoking and gender were included in the risk factor assessment of the DM-LID group, but there was no statistical significance. The clinical manifestations of ILD mainly include the symptoms and signs of cough, chest tightness/shortness of breath, clubbing fingers, and Velcro rales. Some patients also have systemic symptoms such as fever, chest pain, fatigue, and joint pain. This study analyzed the above clinical manifestations. There was a significant difference between the two groups in the clinical manifestations related to ILD, such as cough, chest tightness/shortness of breath, and velcrol rale. It suggested that patients with DM should be alert to the occurrence of ILD in the presence of the above symptoms, but there were limitations in diagnosing ILD only from clinical symptoms.
At present, the diagnosis of ILD is mainly based on clinical history, imaging examination, pulmonary function test, blood gas analysis. [14]. However, such tests are easily disturbed by other factors, such as patients with pulmonary infection and airway obstructive diseases. Autoantibodies are convenient and effective prognostic biomarkers in the clinical practice of ILD related to autoimmune rheumatism [15], so simple and easy to achieve serological indicators are included in the evaluation of risk factors. For example, this study also analyzed transaminase, IgG, white egg white, ferritin, KL-6, CRP, ESR, urea nitrogen. There were significant differences in creatine kinase and other laboratory indexes between DM-ILD patients and Amnon ILD patients. It was found that the ESR, CRP, and KL-6 of the DM-ILD group were significantly increased, suggesting that the increase of ESR, CRP, and KL-6 is the influencing factor of ILD in DM patients. DM also has other characteristics in blood testing, such as elevated serum ferritin. The ferritin level is related to the severity of DM and ILD [16], but there is no statistical significance of ferritin in this research.