Characteristics and risk factors of mortality in patients with systemic sclerosis-associated interstitial lung disease
Hye Jin Jang, Ala Woo, Song Yee Kim, Seung Hyun Yong, Youngmok Park, Kyung Soo Chung, Su Hwan Lee, Ah Young Leem, Sang Hoon Lee, Eun Young Kim, Ji Ye Jung, Young Ae Kang, Young Sam Kim, Moo Suk Park
Abstract
Background Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by dysregulation of fibroblast function, which often involves the lungs. Interstitial lung disease (ILD) associated with SSc (SSc-ILD) is a major cause of death among patients with SSc. Our study aimed to identify risk factors for mortality and compare the clinical characteristics of patients with SSc-ILD.Patients and methods Patients were retrospectively enrolled between 2010 and 2018 in a tertiary hospital in Korea. Patients with SSc-ILD were classified depending on the first pulmonary function test or radiologic findings: extensive (n = 46, >20% disease extent on computed tomography (CT) or forced vital capacity [FVC] < 70% in indeterminate cases) and limited (n = 60, <20% disease extent on CT or FVC ≥70% in indeterminate cases).Results Patients in the extensive group were younger (mean age ± SD 49.3 ± 11.5) than those in the limited group (53.9 ± 12.5, p = .067) at diagnosis. The extensive group showed frequent pulmonary hypertension (43.5% vs. 16.7%, p = .009) and higher erythrocyte sedimentation rate (61.3 ± 33.7 vs. 42.1 ± 26.0, p = .003) and mortality (32.6%, mean duration of follow-up, 100.0 ± 44.7 months vs. 10.0%, 86.0 ± 53.4 months, p = .011). ILD was detected within five years from the first visit (median years 3.5 (1.0, 6.0) vs. 4.5 (0.6, 9.0), survivors vs. non-survivors), and mortality occurred in 19.8% of all patients during a 15-year follow-up. Older age, lower FVC, and initial disease stage (limited or extensive) were associated with mortality, but FVC decline was similar in the limited and extensive groups, such as 15–20% in the first year and 8–10% in the next year, regardless of the initial extent of the disease.Conclusions Approximately 10% of patients with SSc-ILD in the limited and extensive group showed progression. ILD was detected at a median of less than five years from the first visit; therefore, it is necessary to carefully monitor patients’ symptoms and signs from an early stage. Long-term surveillance is also required.Key messagesPatients with systemic sclerosis-interstitial lung disease manifested a heterogeneous disease course.Approximately 10% of the patients in the limited group showed progression, which was similar to the proportion of patients in the extensive group.Interstitial lung disease was detected at a median of less than five years from the first visit.