Longitudinal Trajectories of Antisynthetase Syndrome-Associated Interstitial Lung Disease

Objectives: Interstitial lung disease (ILD) is the principal determinant of morbidity and mortality in antisynthetase syndrome (ASyS). Data regarding ASyS-ILD trajectory phenotypes and factors influencing ILD clinical course remain scarce. We aimed to identify longitudinal ILD trajectories in patients with ASyS-ILD. Methods: A total of 92 patients with ASyS and ILD diagnosed by high-resolution computed tomography (HRCT), with forced vital capacity (FVC) measurement at ILD diagnosis and at least 1 additional measurement during follow-up, were included. Latent class mixed models (LCMMs) and linear mixed-effects models were performed to determine groups of patients with similar FVC trajectories and to identify risk factors associated with longitudinal FVC change. Results: The 3-class model demonstrated the best fit. Class 1 (n = 17) had intermediate baseline FVC but declined over time, with higher rates of ILD relapse, pulmonary hypertension, and chronic respiratory failure. Class 2 (n = 44) included younger patients with higher baseline FVC that remained stable during follow-up. Class 3 (n = 31) had lower baseline FVC and more rapidly progressive ILD at diagnosis but improved over time. In mixed-effects models, nonspecific interstitial pneumonia and organizing pneumonia patterns were associated with a more favorable longitudinal FVC trajectory (β = 6.5; 95%CI, 1.8-11; P = .008 and β = 7.7; 95%CI, 2.0-13; P = .009, respectively). Conclusions: We identified 3 phenotypes of ILD trajectories in patients with ASyS, including 1 group with declining FVC and poor respiratory prognosis. HRCT ILD pattern was the factor most predictive of longitudinal FVC change.