Risk factors for progression and prognosis of primary Sjögren's syndrome-associated interstitial lung disease in a Chinese population.

OBJECTIVE This study explored differences between primary Sjogren'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.