Whether in DM, CADM, or CDM, anti-MDA5 antibody-positive patients had consistently significantly higher rates of mortality, 1-year mortality, RP-ILD, ILD, fever, cough or dyspnea, heliotrope rashes, higher PLR, and higher levels of LDH, ferritin, and CEA than anti-MDA5 antibody-negative patients. This evidence concerns the gene CEACAM5 and clinically amyopathic dermatomyositis.