Idiopathic inflammatory myopathy-related interstitial lung disease

multicentric study in Córdoba

Abstract

Interstitial lung disease (ILD) is one of the most frequent systemic complications of idiopathic inflammatory myopathies (IIM). However, there is limited knowledge about this disorder. The purpose of the present work was to describe the clinical, radiological, and pulmonary function of patients with idiopathic inflammatory myopathy-related interstitial lung disease.

We conducted a retrospective studied with patients with diagnosis of IIM by ARC/EULAR 2017 in 3 rheumatology Units at Córdoba between 2017 and 2021. Demographic data, type of myopathy, clinical manifestations, autoantibody profile, pulmonary function, and tomographic patterns were analyzed. Quantitative variables were expressed as mean and standard deviation. Categorical variables were calculated using absolute and percentage distributions. The Kruskal Wallis test was applied in the comparison of means (after applying the Shapiro Wilks normality test) and the chi-square test in the correlation of categorical variables. p≤0.05 was considered significant.  

We included 47 patients, 26 with ILD (55.3%). In this subgroup, the mean age was 48.3 years, 80.8% were female and 23.1% were smokers. 84.6% had dyspnea and 50% cough.  50% had muscle weakness. Median FVC was 62.2% and median DLCO was 52.5% of predicted. 50% of the patients had oxygen desaturation during the 6-minute walk test. The predominant tomographic pattern was NSIP (57.7%), followed by UIP (34.6%). The most frequent specific autoantibodies were: Jo-1 (38.5%), AMA (7.7%), Pm ScL100(4%) and SRP (4%). ANA was positive at 26.9%. Regarding antibodies associated with myositis, 7.7% had Ro (+) and 3.8% RNP (+). Patients with ILD had more frequency of antisynthetase syndrome (46.2% vs 0%; p=0.0008), respiratory manifestations (dyspnea 84.6% vs 14.3%; p=0.0001, cough 50.0% vs 14.3%; p=0.013) and anti-Jo1(+) (38.5% vs 14.3%; p=0.042) compared to those without lung involvement.

In our cohort of patients with ILD associated with autoimmune inflammatory myopathies had more frequent positive anti-Jo1 antibody, tomographic pattern of NSIP, and restrictive pulmonary function.