Factors for progressive pulmonary fibrosis in connective tissue disease-related interstitial lung disease

Background: Progressive fibrosis can occur in connective tissue disease (CTD)-related interstitial lung disease (ILD) and make the prognosis worse. Objectives: This study aimed to investigate factors related to progressive pulmonary fibrosis (PPF) phenotype in CTD-ILDs. Design: Medical records of patients diagnosed as CTD and ILD at a single, tertiary hospital in South Korea were retrospectively reviewed. Methods: Patients whose lung functions were followed up for more than a year were included in analysis. PPF was defined as forced vital capacity (FVC) declined ⩾10% or diffusion capacity of carbon monoxide (DLco) ⩾15%. Results: Of 110 patients with CTD-ILD, 24.5% progressed into PPF. Rheumatoid arthritis (RA) and Sjogren’s disease accounted for more than 63% of PPF. Compositions of CTD type were similar between PPF and non-PPF. Clinical characteristics and proportion of usual interstitial pneumonia (UIP) pattern on chest images were also similar between PPF and non-PPF. Approximately 10% of patients in both groups were treated with anti-fibrotic agents. Use of systemic steroids and/or other immunomodulating agents lowered the risk of developing PPF in CTD-ILD patients after adjusting for gender-age-physiology score and smoking status (adjusted odds ratio: 0.25, 95% confidence interval: 0.07–0.85). Conclusion: About a quarter of CTD-ILD progressed into PPF. The use of immunomodulating agents lowered the risk of developing PPF. To improve outcomes of patients, future studies need to detect patients at higher risk for PPF earlier and set up clinical guidelines for treatment strategies in the process of PPF