Evolution of high-resolution CT-scan in systemic sclerosis-associated interstitial lung disease: Description and prognosis factors.

Objective: The aims of our study were to describe the evolution of interstitial lung disease (ILD) extent on HRCT scan in systemic sclerosis (SSc), to identify baseline prognostic factors associated with ILD evolution and to assess whether the evolution of pulmonary function tests (PFTs) correlated with this evolution.

Methods: 58 SSc with ILD (SSc-ILD) patients were included. All HRCT scans and PFTs available were collected. We modelized PFTs and HRCT scans evolution using linear mixed model with random effect.

Results: Patients underwent a median number of 3 HRCT scans (total n = 203) and 5 PFTs (total n = 329), during a mean follow-up of 5.3 ± 4.9 years. Mean SSc duration was 2.5 ± 3.1 years at the diagnosis of ILD. Mean baseline ILD extent was 32.3 ± 28.7%. We found a significant mean progression of ILD extent on serial HRCT scans of 0.92 ± 0.36% per year (p = 0.018). Male sex, diffuse cutaneous SSc (dcSSc), presence of anti-topoisomerase 1 antibodies, a higher DLCO, limited ILD and a low coarseness score at baseline in bivariate analysis, and presence of antitopoisomerase 1 antibodies and a coarseness score of 0 in multivariate analysis, were associated with faster progression of ILD extent over time There was a significant correlation between the progression of ILD extent and the decline of DLCO but only a trend for FVC. ILD extent at baseline and during follow-up was associated with survival.

Conclusion: Male sex, dcSSc, anti-topoisomerase 1 antibodies and a less severe ILD at baseline were associated with a faster progression of ILD over time. Evolution of DLCO significantly correlated with change in ILD extent on HRCT scan. Our study helps defining the profile of patients at risk of experiencing a progression of ILD on HRCT scans.