Risk factors for progression and prognosis of primary Sjögren’s syndrome‐associated interstitial lung disease in a Chinese population

Abstract Objective This study explored differences between primary Sjögren's syndrome‐associated interstitial lung disease (pSS‐ILD) patients with and without ILD progression, and analyzed the factors affecting the progression and prognosis of pSS‐ILD. Methods This study is a retrospective cohort study which enrolled 113 pSS‐ILD patients hospitalized between 2011 and 2017. Results The 3‐year survival rate of the pSS‐ILD patients was 91.15%, and the 5‐year survival rate was 84.07%. Univariate analysis showed that Raynaud's syndrome, hypoproteinemia, extensive lung involvement, possible usual interstitial pneumonia pattern were risk factors for the progression of ILD in patients with pSS‐ILD, and cyclophosphamide was a protective factor for the progression of ILD in patients with pSS‐ILD. Multiple logistic regression analysis showed that extensive lung involvement (odds ratio 4.143, 95% CI: 1.203‐14.267, P < .05) was an independent risk factor for the progression of pSS‐ILD. Cox hazard analysis showed that pSS‐ILD with hypoproteinemia (hazard ratio [HR] 17.758, 95% CI: 4.753‐66.340, P <‐ .05) and extensive lung involvement (HR 3.450, 95% CI: 1.419‐8.390, P < .05) were associated with worse survival of patients. Conclusion Extensive lung involvement is an independent risk factor for the progression of ILD in patients with pSS‐ILD. Hypoproteinemia and extensive lung involvement are independent risk factors for mortality in patients with pSS‐ILD, after controlling for potentially influential variables.