Pulmonary Fibrosis and Progressive Pulmonary Fibrosis in a Prospective Registry of Interstitial Lung Diseases in Eastern Siberia

Interstitial lung diseases (ILD) are part of a large heterogeneous group of diseases that differ in many ways (in their cause, clinical presentation, and response to therapy, etc.), but there are similar pathophysiological mechanisms involved in the development of the inflammation and/or fibrosis of the lungs. Currently, several criteria for pulmonary fibrosis (PF) and progressive pulmonary fibrosis (PPF) are proposed, and the information on the prevalence and characteristics of these conditions is limited. The aim of this study was to evaluate the spectrum of PF and PPF according to the registry of patients with ILD in eastern Siberia. Materials and methods: The study included patients with ILD from all of the medical institutions in the Irkutsk region (eastern Siberia). Each case of ILD (n = 270) was reviewed by a multidisciplinary discussion panel. The ILD patient registry included information on the clinical findings, history, pulmonary function tests, high-resolution computed tomography (HRCT), and histological findings. The follow-up period for the patients varied from 1 to 5 years. Results: Pulmonary fibrosis was detected by HRCT in 104 patients with ILD (38.5%). PF was present in 100% of the patients with IPF and SS-ILD, in 90.9% of the patients with CHP, in 71.4% of the patients with NSIP, and in 60% of the patients with RA-ILD. Sixty-two patients met the criteria for PPF (23.0% of the entire ILD cohort and 59.6% of the patients with PF). PPF occurred most often in the patients with IPF, CHP, IPAF, and SSc-ILD: 100%, 72.7%, 40%, and 38.5% of them, respectively. The variables associated with fibrosis progression included Velcro crackles (OR 18.3, p < 0.001) and late diagnosis (OR 4.1, p < 0.001). Conclusion: Pulmonary fibrosis and progressive pulmonary fibrosis are common in patients with ILD. The high mortality rate of PPF dictates the need for the active, early detection of a progressive fibrosing course of a wide range of ILD and suggests that further studies assessing the effectiveness of the interventions might be warranted.