Lung Disease in Sjögren's Syndrome: Insights From a Reference Center's Population

Background Sjögren's syndrome (SS) is a chronic systemic autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands. Although primarily affecting these glands, the syndrome can also involve several organs. Interstitial lung disease is one of the most severe complications associated with SS. Objectives This study aims to analyze the characteristics of lung involvement in patients with primary SS from a reference medical center's population. Methods Retrospective, longitudinal study of primary SS patients diagnosed until December 2022. Clinical and laboratory data were collected and subjected to statistical analysis using SPSS®. A 95% confidence interval was considered, with statistical significance set at p<0.05. Results A total of 126 patients were included, 95.2% of whom were females, with a mean age at diagnosis of 50 years. The median EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) at diagnosis was 3, which decreased to 1 at the last evaluation. Based on the ESSDAI lung domain, nine patients presented with lung disease at diagnosis. This number increased to 18 by the last assessment. Thoracic tomography showed lung disease in 30 patients, with bronchiectasis being the most common finding. Ten patients presented with interstitial lung disease. Pulmonary function tests were abnormal in 18 patients, and the diffusing capacity of the lungs for carbon monoxide was reduced in 32. Patients with lung disease were more likely to experience a dry cough (p<0.01), have positive SSA antibodies (p<0.05), antinuclear antibody (ANA) >1/320 (p<0.01), positive rheumatoid factor (p<0.01), and low C4-complement during follow-up (p<0.05). Conclusions The authors found an association between clinical and analytical findings and the presence of lung disease in SS patients. Further research is essential to identify optimal predictors of SS-associated lung disease, facilitating early diagnosis and intervention for both SS and its related lung complications.