Clinical characteristics and prognostic markers of anti-MDA5 antibody-positive dermatomyositis-associated interstitial lung disease: a retrospective cohort study.

BACKGROUND: Anti-melanoma differentiation-associated gene 5 (MDA5) positive dermatomyositis-associated interstitial lung disease (DM-ILD) is a severe condition with high mortality, often manifesting as rapidly progressive ILD (RP-ILD). This study aimed to explore potential clinical and laboratory variables associated with mortality in patients with anti-MDA5 + DM-ILD in a small exploratory cohort. METHODS: We retrospectively analyzed 25 patients with anti-MDA5-positive DM-ILD admitted to our institution. Baseline clinical characteristics, imaging features, treatments, and laboratory parameters (collected upon admission) were evaluated. Univariable and multivariable Firth's penalized likelihood logistic regression models were utilized to identify risk factors for mortality. RESULTS: The cohort included 6 males and 19 females (mean age 59.6±11.5 years). During the observation period, 16 patients survived and 9 died. Non-survivors exhibited significantly higher baseline levels of lactate dehydrogenase (LDH) (P=0.02) and D-dimer (P=0.03) compared to survivors. Univariable analysis indicated that both elevated LDH and D-dimer were associated with an increased risk of mortality. However, subsequent multivariable Firth regression analysis, adjusting for age, sex, and erythrocyte sedimentation rate (ESR), demonstrated that elevated baseline D-dimer was identified as a potential parameter associated with increased mortality [adjusted odds ratio (OR) =6.14, 95% confidence interval (CI): 1.69-135.73, P=0.003]. CONCLUSIONS: Baseline D-dimer elevation represents a potential prognostic indicator associated with poor survival in patients with anti-MDA5-positive DM-ILD. Assessing D-dimer levels upon admission provides crucial insights into the underlying severe vasculopathy, facilitating early risk stratification and the timely implementation of targeted therapies.