Tracking Impact of Interstitial Lung Disease in Systemic Sclerosis in a Complete Nationwide Cohort

• Published in: American journal of respiratory and critical care medicine Vol. 200; no. 10; pp. 1258 - 1266
• Main Authors: Hoffmann-Vold, Anna-Maria, Fretheim, Håvard, Halse, Anne-Kristine, Seip, Marit, Bitter, Helle, Wallenius, Marianne, Garen, Torhild, Salberg, Anne, Brunborg, Cathrine, Midtvedt, Øyvind, Lund, May Brit, Aaløkken, Trond M., Molberg, Øyvind
• Format: Journal Article
• Language: English
• Published: United States American Thoracic Society 15.11.2019; HighWire Press
• Subjects: Adult; Aged; Cohort Studies; Disease management; Female; Humans; Lung Diseases, Interstitial - diagnosis; Lung Diseases, Interstitial - epidemiology; Lung Diseases, Interstitial - therapy; Male; Medical screening; Middle Aged; Mortality; Norway - epidemiology; Prognosis; Scleroderma; Scleroderma, Systemic - complications; Scleroderma, Systemic - mortality; Scleroderma, Systemic - therapy; Survival Rate; Tomography; Norway; epidemiology; systemic sclerosis; autoimmune disease; pulmonary fibrosis
• ISSN: 1073-449X; 1535-4970; 1535-4970
• DOI: 10.1164/rccm.201903-0486OC

Interstitial lung disease (ILD) represents a major challenge in systemic sclerosis (SSc), but there are no precise, population-based data on its overall impact, limiting opportunities for screening and management strategies. Evaluate impact of ILD in a unique, nationwide, population-based SSc cohort. ILD was assessed prospectively in the Norwegian SSc (Nor-SSc) cohort, including all 815 patients with SSc resident in the country from 2000 to 2012. Lung high-resolution computed tomography (HRCT) scans were available for fibrosis quantification at baseline (  = 650, 80%) and follow-up. Pulmonary function tests were assessed at baseline (  = 703, 86%) and follow-up. Vital status and standardized mortality ratios (SMRs) were estimated at study end (2018) in the 630 incident Nor-SSc cases and 15 individually matched control subjects. Cumulative survival rates were computed. At baseline, 50% of the subjects with SSc (  = 324) had ILD by HRCT and 46% displayed pulmonary function declines consistent with ILD progression. Mortality correlated with extent of lung fibrosis as SMR increased from 2.2 with no fibrosis to 8.0 with greater than 25% fibrosis. SMR was inversely related to baseline FVC% and increased at all FVC levels below 100%. In patients with normal-range baseline FVC (80-100%), the 5- and 10-year survival rates correlated with presence or absence of lung fibrosis, being 83% and 80%, respectively, with no fibrosis and 69% and 56%, respectively, with lung fibrosis (  = 0.03). The mere presence of ILD at baseline appears to affect outcome in SSc, suggesting that all patients with SSc should undergo a baseline pulmonary function test and lung HRCT screening to diagnose ILD early and tailor further management.