Clinical characteristics of systemic sclerosis patients with occupational silicosis

To explore the clinical characteristics of systemic sclerosis complicated with silicosis. The systemic sclerosis patients treated in the Guangxi Workers’ Hospital and the People's Hospital of Guangxi Zhuang Autonomous Region from January 2000 to December 2020 were divided into the systemic sclerosis with silicosis group and the systemic sclerosis without silicosis group. Survival analysis was performed using Kaplan–Meier estimates the Cox proportional hazards model. A propensity score matching was applied in order to avoid the selection bias.

Over the past 20 years, 72 systemic sclerosis patients with silicosis and 238 systemic sclerosis patients without silicosis were treated in the two hospitals. The systemic sclerosis patients with silicosis group had more males (P < 0.000),lower mean age at onset of SSc (P < 0.000), more frequent occurrence of weight loss (P = 0.028), smoking (P < 0.000), tuberculosis (P < 0.000), cardiac involvement (P < 0.000), ILD (P = 0.017), pulmonary hypertension (P = 0.024), elevated BNP (P < 0.000). With regards to the multivariate Cox regression analysis, silicosis was related with a higher overall mortality before (HR = 3.666, 95% CI = 1.440–11.234, p = 0.025) and after the propensity score matching analysis (HR = 2.817, 95% CI = 1.196–10.764, p = 0.014). Independent risk factors for overall mortality were Gangrene (HR = 3.003, 95% CI = 1.343–9.431), Cardiac involved (HR = 5.370, 95% CI = 1.910–15.472), Scl-70 (HR = 3.569, 95% CI = 1.333–10.869), Elevated BNP (HR = 2.135, 95% CI = 1.293–9.564).

Concomitant silicosis worsens systemic sclerosis patients’ prognoses. Gangrene, Scl-70, elevated BNP and cardiac involvement are independent risk factors for overall mortality.