Clinical features and prognostic factors of anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis with rapidly progressive interstitial lung disease in Chinese patients

Abstract

Objective: The objective of this study is to investigate clinical features and prognostic factors of antimelanoma differentiation-associated gene 5 (anti-MDA5)-positive dermatomyositis with rapidly progressive interstitial lung disease (RP-ILD) in Chinese patients.

Methods: Clinical features and prognostic factors of patients with newly diagnosed or recurrent dermatomyositis patients were retrospectively analyzed. All patients were divided into the anti-MDA5-positive or negative dermatomyositis, and with or without RP-ILD groups. Clinical features and prognostic factors were statistically compared among different groups.

Results: The serum ferritin (SF) levels (1500.0 [658.80, 1844.0]) and γ-glutamyl transpeptidase (γ-GT) (125.5 [61.0, 232.0] vs. 28 [16.0, 41.0], Z = 5.528; p < .001) were markedly higher, and phosphocreatine myoenzyme (CK) (73.0 [42.0, 201.0] vs. 1333.0 [79.0, 8000.0], Z = -2.739, p = .006), serum albumin level (32.51 ± 5.23 vs. 35.81 ± 5.88, t = -2.542, p = .013), and lymphocyte count (0.80 ± 0.36 vs. 1.45 ± 0.77, t = -4.717, p < .001) were lower than those in anti-MDA5-negative counterparts. Among patients with anti-MDA5 antibody (Ab) with RP-ILD, the SF level (1531.0 [1163.8, 2016.5] vs. 584.9 [564.8, 1042.5], Z = 2.664, p = .008), γ-GT (134.0 [81.0, 204.5] vs. 123.0 [76.0, 189.0], Z = 3.136, p = .002) and positive rate of anti-RO-52 Ab (90.9% vs. 50.0%, χ² = 7.222, p = .013) were higher and lymphocyte count (0.79 ± 0.38 vs. 1.32 ± 0.74, t = -3.025, p = .029) was lower than those in their counterparts without RP-ILD. The SF level of anti-MDA5 nonsurvivors (1544 [1447.32, 2089.0] vs. 584.9 [515.7, 1500.0], Z = 2.096, p = .030), anti-RO-52 Ab-positive rate ([16/18, 88.9%] vs. [9/16, 56.2%], χ² = 4.636, p = .031) were higher than those in survivors. Lymphocytopenia was a risk factor for RP-ILD and death of patients with anti-MDA5-positive dermatomyositis. The area under receiver operating characteristic curve was 0.888 (95% confidence interval: 0.756, 1.000; p < .001), the sensitivity was 85.7%, the specificity was 93.8%, and Youden's index was 0.795.

Conclusions: Anti-MDA5-positive dermatomyositis patients are prone to developing RP-ILD. Declined lymphocyte count is a critical risk factor for RP-ILD, probably acting as a simple and effective predictor for Chinese patients with anti-MDA5-positive dermatomyositis.

Keywords: anti-MDA5 antibody; dermatomyositis; rapidly progressive interstitial lung disease.