In this study, by comparing the general data, laboratory findings of patients with positive and negative anti-MDA5 antibodiesDeaths were analyzed to clarify whether anti-MDA5 antibodies are affected by age, gender, and treatment modality, to reveal common complications and abnormal laboratory test indices in positive patients, and to investigate the effect of positive anti-MDA5 antibodies on cause-specific mortality in middle-aged and elderly PM/DM patients to help in disease prediction diagnosis and prognosis evaluation [20–24]. The gene discussed is IFIH1; the disease is polymyositis.