Predictors and Mortality of Rapidly Progressive Interstitial Lung Disease in Patients With Idiopathic Inflammatory Myopathy: A Series of 474 Patients.

Yuhui Li,Jing He,Shiming Li,Xiaohui Jia,Xiaolin Sun,Xiaojuan Gao,Yuzhou Gan,Yan Xu,Yimin Li,Xuewu Zhang,Renli Chen

doi:10.3389/fmed.2020.00363

Abstract

Objective: This study was conducted to identify the characteristics and prognosis of rapidly progressive interstitial lung disease (RP-ILD) in idiopathic inflammatory myopathy (IIM) and to assess the predictors for poor survival of RP-ILD in IIM.Methods: A total of 474 patients with IIM were enrolled retrospectively according to medical records from Peking University People's Hospital. Clinical and laboratory characteristics recorded at the diagnosis of patients with RP-ILD and chronic ILD (C-ILD) were compared. The Kaplan–Meier estimator and univariate and multivariate analyses were used for data analysis.Results: ILD was identified in 65% (308/474) of patients with IIM. Patients with ILD were classified into two groups based on lung features: RP-ILD (38%, 117/308) and C-ILD (62%, 191/308). RP-ILD resulted in significantly higher mortality in IIM compared with C-ILD (27.4 vs. 7.9%, P < 0.05). In this study, by comparing IIM patients with and without RP-ILD, a list of initial predictors for RP-ILD development were identified, which included older age at onset, decreased peripheral lymphocytes, skin involvement (periungual erythema, skin ulceration, and subcutaneous/mediastinal emphysema), presence of anti-MDA5 antibody, serum tumor markers, etc. Further multivariate Cox proportional hazards model analysis identified that anti-MDA5 positivity was an independent risk factor for mortality due to RP-ILD (P < 0.05), and lymphocytes <30% in BALF might also be associated with poor survival of myositis-associated RP-ILD (P < 0.05).Conclusion: Our study shows that RP-ILD results in increased mortality in IIM. Anti-MDA5 positivity and a lower lymphocyte ratio in BALF might be the predictive factor of mortality due to RP-ILD.

Highlights

Idiopathic inflammatory myopathy (IIM) is a group of systemic autoimmune diseases characterized by skin rash, proximal muscle weakness, and extramuscular manifestations, such as arthralgia, fever, and interstitial lung disease (ILD)
The study cohort included 505 patients with myositis and 31 patients with other autoimmune diseases (11 patients overlapped with systemic lupus erythematosus (SLE), 9 patients overlapped with systemic sclerosis (SSc), 9 patients overlapped with rheumatoid arthritis (RA), 2 patients overlapped with SLE+SSc) were excluded
A total of 474 patients with PM/DM/clinically amyopathic dermatomyositis (CADM) were enrolled in this study, including 87.6% (369/474) females with a mean age of 49.7 ± 14.0 years (Table 1)

Summary

Introduction

Idiopathic inflammatory myopathy (IIM) is a group of systemic autoimmune diseases characterized by skin rash, proximal muscle weakness, and extramuscular manifestations, such as arthralgia, fever, and interstitial lung disease (ILD). Myositis-associated ILD is one of the leading extramuscular features, occurring in 20–80% of all PM/DM/CADM patients [3, 4]. Progressive ILD (RPILD) in IIM is a life-threatening subtype of myositis-associated ILD, which tends to be resistant to high-dose glucocorticoid treatment and immunosuppressants [4,5,6]. Some patients with RP-ILD decline within weeks, but for other patients, the time to ILD-induced deterioration is on the order of years [8], and the 5-year survival rate is more than 85% in myositis-associated ILD [9, 10]. It is difficult to predict whether patients with myositis-associated ILD will develop fatal disease progression at the early stage of the disease. It is necessary to identify potential factors to predict survival of patients with myositis-associated RP-ILD in the early stage of disease development

Methods

Results

Conclusion