Characteristics and mortality in primary Sjögren syndrome–related interstitial lung disease

Aim of the study was to determine the characteristics and prognosis, and to identify the risk factors for mortality in patients with primary Sjögren syndrome (pSS) with interstitial lung disease (pSS-ILD). A total of 1422 patients with SS were screened and 178 patients with pSS-ILD were recruited. The medical records and outcomes were retrospectively reviewed. Overall survival and case control study were performed to explore the predictors of death. Among 178 pSS-ILD patients, 87.1% were women. Mean age was 61.59 ± 11.69-year-old. Median disease duration was 72.0 (24.0, 156.0) months. Nonspecific interstitial pneumonia was the predominant high-resolution computed tomography pattern (44.9%). Impairment in diffusion capacity was the most common abnormality of pulmonary function test (75.8%) and the most severe consequence. Type 1 respiratory failure and hypoxia were observed in 15.0% and 30.0% patients, respectively. Mean survival time after confirmation of pSS-ILD diagnosis was 9.0 (6.8, 13.0) years. The 10-year survival rate for all patients with pSS-ILD was 81.7%. Forty-four (24.7%) of 178 patients died during the follow-up period. The most predominant cause of death was respiratory failure (n = 27). Twenty-seven patients died of ILD and formed study group. The 78 patients who survived formed control group. Age and smoking were risk factors for mortality in patients with pSS-ILD. In addition, severity of ILD, as reflected by high-resolution computed tomography, pulmonary function test, and arterial blood gas, was an independent risk factor. However, inflammation status (erythrocyte sedimentation rate, C-reactive protein) and anti-Sjögren syndrome–related antigen A and anti-Sjögren syndrome–related antigen B were not. ILD is a severe complication of pSS. Age, smoking, and severity of lung involvement are more critical for prognosis rather than inflammation status and autoantibodies.