Ground-glass opacity score predicts the prognosis of anti-MDA5 positive dermatomyositis: a single-centre cohort study

OBJECTIVE: Dermatomyositis (DM) positive with anti-melanoma differentiation-associated gene 5 (anti-MDA5-DM) is a systemic autoimmune disease with high mortality. This study aimed to explore the risk factors of death in anti-MDA5-DM and validate a prediction model for all-cause mortality in anti-MDA5-DM. METHOD: We conducted a retrospective study using a single-centre cohort of patients with newly onset anti-MDA5-DM from June 1, 2018 to August 31, 2021. Patients were divided into four groups according to baseline ground-glass opacity (GGO) score: Group A, GGO ≤ 1; Group B, 1 < GGO ≤ 2; Group C, 2 < GGO ≤ 3; Group D, GGO > 3. The primary outcome was death during the follow-up. Secondary outcomes included death within 3, 6, 12 months, severe infection, and remission during the first 12 months. RESULTS: A total of 200 patients were included in the study. Based on multivariable Cox regression, the prognostic factors at baseline were identified as CRP > 5 mg/L, serum ferritin (SF) > 600ng/ml, positive anti-Ro52 antibody, prophylactic use of compound sulfamethoxazole (SMZ Co), four-category GGO score: GGO ≤ 1, 1 < GGO ≤ 2, 2 < GGO ≤ 3, GGO > 3. The final mortality of four groups was 16.4, 22.2, 48.5, 92.0%, respectively. Compared with Group A, the Hazards Ratio (HR) of Group B was 1.408, (p = 0.408), HR of Group C was 3.433 (p = 0.005), HR of Group D was 4.376 (p = 0.001). CONCLUSIONS: GGO score is a reliable predictor for risk stratification in anti-MDA5-DM and may provide guidance for individualized managements of patients.