Long-term clinical course and outcome in patients with primary Sjögren syndrome-associated interstitial lung disease

Interstitial lung disease (ILD) is the most common lung manifestation in patients with Sjögren syndrome (SJS) and is associated with poor outcomes. This study aimed to investigate the long-term clinical course and prognostic factors in patients with SJS-ILD. Clinical data and high-resolution computed tomography (HRCT) images of 62 patients with primary SJS-ILD were retrospectively analyzed (biopsy-proven cases, n = 16). The mean patient age was 59.8 years; 83.9% of the patients were females, and 38.7% showed a usual interstitial pneumonia (UIP) pattern on HRCT. The median follow-up period was 61.5 months. During follow-up, 15 patients (24.2%) died, 7 (11.3%) experienced acute exacerbation (AE), and 27 (43.5%) progressed. The 1-, 3- and 5-year survival rates were 93.5%, 85.8%, and 81.1%, respectively. Age (hazard ratio [HR]: 1.158, P = 0.003), C-reactive protein (CRP) level (HR: 1.212, P = 0.045), FVC (HR: 0.902, P = 0.005), and a UIP pattern on HRCT (HR: 4.580, P = 0.029) were significant prognostic factors in multivariable Cox analysis. In conclusion, death, AE, and ILD progression occurred in 25%, 10%, and 50% of the patients with SJS-ILD, respectively. Older age, higher CRP level, lower FVC, and a UIP pattern on HRCT indicated poor prognosis.