Risk factors and prognosis of interstitial lung disease for primary Sjögren syndrome patients: A retrospective case‒control study

Objective To determine the prevalence, clinical features, risk factors, and prognosis of interstitial lung disease (ILD) in patients with primary Sjogren's syndrome (pSS). Methods Data from 274 pSS patients from August 2013 to August 2022 were reviewed. The clinical features of pSS with ILD were revealed. Logistic regression was used to determine risk factors for ILD in pSS patients. Survival analysis and Cox regression were used to analyse the prognosis and prognostic factors of pSS patients. Results In pSS patients, the prevalence of ILD was 22.3% (61/274). The pSS patients with ILD were characterized by a late onset and long disease course, with a nonspecific interstitial pneumonia (NSIP) pattern as the predominant high-resolution computed tomography (HRCT) finding. Logistic regression results indicated that an age over 50 years old (OR 4.786, 95% CI 1.602–14.299; P = 0.005 ), purpuric rash (OR 4.695, 95% CI 1.537–14.339; P = 0.007 ), AMA-M2 antibody positivity (OR 2.582, 95% CI 1.166–5.722; P = 0.019 ), and diabetes (OR 2.514, 95% CI 1.025–6.167; P = 0.044 ) were risk factors for ILD in pSS patients. Cox regression results showed that advanced age (HR 1.240, 95% CI 1.088–1.413; P = 0.001 ) and cancer history (HR 8.411, 95% CI 1.771–39.934; P = 0.007 ) were risk factors for pSS patient survival. Conclusion This study showed that pSS patients with ILD tended to have a late onset and long course of pSS. An age over 50 years, purpuric rash, AMA-M2 antibody positivity, and diabetes were risk factors for ILD in pSS patients. Advanced age and cancer history were prognostic factors in pSS patients. Key Points • This study showed that pSS patients with ILD tended to have a late-onset and lengthy course of pSS, with the NSIP pattern as the predominant lung image. • The risk factors for ILD in pSS patients determined in this study were an age over 50 years, purpuric rash, AMA-M2 antibody positivity, and diabetes. • The prognostic risk factors for pSS patients were advanced age and cancer history.