Pneumoconiosis combined with connective tissue disease in China: a cross-sectional study

Objective To describe the prevalence, clinical features and potential risk factors of pneumoconiosis in combination with connective tissue disease (CTD) or positive autoantibodies. Design Cross-sectional study. Setting A retrospective study of adults recruited in China between December 2016 and November 2021. Participants A total of 931 patients with pneumoconiosis at Beijing Chao-Yang Hospital were enrolled in this study; of these, 580 patients were included in the final analysis. Main outcome measures Pneumoconiosis combined with CTD or positive autoantibodies was a major adverse outcome. Results In total, 13.8% (80/580) of the patients had combined pneumoconiosis with CTD, among whom the prevalence of CTD was 18.3% (46/251) in asbestosis and 11.4% (34/298) in silicosis/coal mine workers' pneumoconiosis. In comparison to the general Chinese adult population, the relative risk of various CTD in pneumoconiosis, including rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, primary Sjogren's syndrome, idiopathic inflammatory myopathy and antineutrophil cytoplasmic antibodies-associated vasculitis, were 11.85, 12.12, 127.40, 4.23, 9.94 and 644.66, respectively. Multivariate analysis revealed that female sex (OR 2.55, 95% CI 1.56 to 4.17) and a later stage of pneumoconiosis (OR 2.04, 95% CI 1.24 to 3.34) were the independent risk factors for CTD in patients with pneumoconiosis (all p<0.050). Conclusion CTD is highly prevalent in patients with pneumoconiosis, especially in patients of asbestosis, and silicosis/coal mine workers' pneumoconiosis. Female sex and later stages of pneumoconiosis are associated with an increased risk of combined with CTD.