A retrospective analysis of clinical characteristics of systemic sclerosis-associated interstitial lung disease

Systemic sclerosis (SSc) is a rare, complex, chronic, progressive, severe, often life-threatening, fibrosing, heterogeneous autoimmune connective tissue disease with immune dysfunction and limited treatment options. Interstitial lung disease (ILD) is common in SSc. To study the clinical characteristics of systemic sclerosis-associated interstitial lung disease (SSc-ILD) will provide evidence for the early diagnosis, treatment decision-making, and prognosis of SSc-ILD patients. One hundred and seventy-five patients with SSc were retrospectively enrolled and divided into SSc-ILD group and SSc-non-ILD group. The general clinical characteristics, autoantibodies, laboratory test, thorax high-resolution computed tomography (HRCT), pulmonary function testing, stratification, and treatment options were compared between the 2 groups. The risk factors of SSc-ILD were also analyzed. One hundred and twenty-four SSc-ILD patients (70.9%) and 51 SSc-non-ILD patients (29.1%) were in 175 SSc patients. Raynaud phenomenon, skin swelling, and joint involvement were the top 3 initial symptoms. Sixty-seven SSc-ILD patients (54.1%) showed new onset or progression of ILD on HRCT, which were heterogeneous. The significantly increased indicators in SSc-ILD group were gastrointestinal involvement (P = .003), antinuclear antibody (ANA) (P = .006), anti-Scl-70 (P <.001), anti-SSA (P = .008), and rheumatoid factor (P = .04), erythrocyte sedimentation rate (ESR) (P = .005), CRP (P = .000), IL-6 (P = .001), globulin (P = .006), IgG (P = .002), IgA (P = .001), while the decreased indicators were mean corpusular hemoglobin concerntration (P = .036), albumin (P = .046), liver dysfunction (P = .018), and FVC% (P = .006). Positive anti-Scl-70 antibody and decreased FVC% were independent risk factors for SSc-ILD. The incidence of ILD occurrence and progression was significantly higher in patients with anti-Scl-70 antibody, diffuse cutaneous systemic sclerosis (dcSSc) plus anti-Scl-70 antibody, ESR ≥50 mm/h, and CRP ≥5.00 mg/L (P <.05). Based on the predictive factors (gastrointestinal involvement, joint involvement, positive anti-Scl-70 antibody, liver dysfunction, duration of disease, FVC%, mean corpusular hemoglobin concerntration, ESR, CRP, IgG, IgA, globulin, and albumin), independent risk factors (anti-Scl-70 antibody and decreased FVC%), clinical phenotypic and autoantibody stratification, HRCT heterogeneity, and atypical initial symptoms, it may be seized the "window of opportunity" with early diagnosis may exist for preventing the irreversible progression of pulmonary fibrosis of SSc-ILD patients.