Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune inflammatory muscle disorders characterized by muscle weakness and multisystem involvement, especially in skin and lungs. Polymyositis (PM) and dermatomyositis (DM) are the two main phenotypes of IIMs. PM/DM are associated with considerable mortality, with 10-year survival rate reported to be 45.7–90% in previous studies [1–4]. Interstitial lung disease (ILD) has been recognized as one of the most common systemic complications and has a significant impact on the prognosis of PM and DM, accompanied with deteriorating respiratory parameters such as forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (DLCO), and is a major cause of worse prognosis [4].