Clinical Features, Prognostic Factors, And Outcome Of Anti-Mda5 Positive Dermatomyositis With Rapidly Progressive Interstitial Lung Disease: A Multicenter Study Of 238 Patients

Background: Anti-melanoma differentiation-associated gene 5 positive dermatomyositis (anti-MDA5+ DM) is typically amyopathic and associated with a life-threatening, therapy-resistant, rapidly progressive interstitial lung disease (RP-ILD). Objectives: The present study aims to characterize the prognostic factors and long-term outcome of MDA5+ DM -associated RP-ILD. Methods: A multicenter retrospective study was performed across ten tertiary hospitals in China between January 1, 2018 to December 31, 2019. Results: A total of 238 patients (170 women) with MDA5+ DM enrolled into this retrospective clinical study. The mean age was 53.0 ± 12.2 years. The median follow-up duration was 6.3 ± 12.2 months. Of those 238 anti-MDA5+ patients, ILD is commonly observed in 213 patients, and RP-ILD occurred in 35.29% (84/213) of these patients (RP-ILD defined as progressive dyspnea occurs within 1 month after the onset of respiratory symptoms, and chest radiography or pulmonary function test show progressive interstitial abnormalities). The mortality rate of RP-ILD patients within the 6 months was 58.3% (49/84) in our cohort. Death peaked the first three months after diagnosis, occupying 84.8% (39/46) of died RP-ILD patients. Cox univariate proportional hazard analysis showed that age, gender, disease duration, abnormal laboratory features (LDH, CK, ESR and CRP), anti-Ro52 autoantibody and anti-MDA5 grade were related to the risk of occurrence of RP-ILD in patients with MDA5+ DM. The Cox proportional hazards model identified the disease duration [odds ratio (OR) 0.81 (95% CI 0.68, 0.96), P=0.016] as a protective factor, and anti-Ro52 autoantibody [OR 5.82 (95% CI 1.72, 19.73), P=0.005] as independent risk factors for the occurrence of RP-ILD in MDA5+ DM patients. The 6-month all-cause mortality rate of RP-ILD patients was 58.3% (49/84). Conclusion: Combined with anti-Ro52 in Myositis-specific antibodies was associated with the occurrence and long-term mortality in MDA5+ DM -associated RP-ILD patients. The results suggest poor overall survival among patients with MDA5+ DM -associated RP-ILD. Survival during the first 6 months is crucial for long-term survival. Early recognition and prompt treatment of this high-risk group of MDA5+ DM -associated RP-ILD patients are therefore important. Disclosure of Interests: None declared