Longitudinal Trajectories of Antisynthetase Syndrome-associated Interstitial Lung Disease

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.

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 one 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.

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).

We identified three phenotypes of ILD trajectories in patients with ASyS, including one group with declining FVC and poor respiratory prognosis. HRCT ILD pattern was the factor most predictive of longitudinal FVC change.