Prognostic analysis of MDA5‐associated clinically amyopathic dermatomyositis with interstitial lung disease

Abstract Objective To investigate the prognostic factors of patients with anti‐melanoma differentiation‐associated gene 5 (MDA5) positive clinically amyopathic dermatomyositis (CADM) and interstitial lung disease (ILD). Methods A retrospective analysis was conducted on clinical data of 125 patients with anti‐MDA5 + CADM‐ILD collected from 10 branches in eastern China between December 2014 and December 2022. Prognostic factors were analyzed using χ 2 test, Log‐rank test, COX and logistic regression analysis. Results In this cohort, 125 anti‐MDA5 + CADM‐ILD patients exhibited a rapidly progressive interstitial lung disease (RPILD) incidence of 37.6%, and an overall mortality rate of 24.8%. One patient was lost to follow‐up. After diagnosis of RPILD, a mortality rate of 53.2% occurred in patients died within 3 months, and that of 5.6% appeared in those who survived for more than 3 months. Multiple factor analysis revealed that C‐reactive protein (CRP) ≥ 10 mg/L ( p = 0.01) and recombinant human tripartite motif containing 21 (Ro52) (+) ( p = 0.003) were associated with a higher risk of RPILD in anti‐MDA5 + CADM‐ILD patients; CRP ≥ 10 mg/L ( p = 0.018) and the presence of RPILD ( p = 0.003) were identified as the factors influencing survival time in these patients, while arthritis was the protective factor ( p = 0.016). Conclusion Patients with anti‐MDA5 + CADM‐ILD will have a higher mortality rate, and the initial 3 months after diagnosis of RPILD is considered the risk window for the dismal prognosis. Patients with CRP ≥ 10 mg/L, Ro52 (+) and RPILD may be related to a shorter survival time, while patients complicated with arthritis may present with relatively mild conditions.