Clinical Characteristics and Outcomes of Interstitial Lung Disease in Primary Sjögren's Syndrome: A Retrospective Cohort Study.

Objectives: To describe the characteristics of primary Sjögren's syndrome (pSS) patients with interstitial lung disease (ILD) and to assess treatment response.

Methods: All patients of pSS from 2010 to 2019 were retrospectively identified. Lung function tests, high resolution computed tomography (HRCT) findings, and treatment outcomes were analysed.

Results: Out of 550 patients with pSS, ILD was detected in 33 patients (frequency of 6 %). The mean(±SD) age at the diagnosis of pSS was 50 (± 9.3) years. 28/33(84.8%) were females. ILD onset preceded pSS diagnosis in 2 (6%) patients, simultaneously diagnosed in 21 (63.6%) patients and developed after pSS onset in 10 (30.3%) patients. 5 patients (15.15 %) were asymptomatic for ILD. Non-specific interstitial pneumonia (NSIP) accounted for the most frequent ILD subtype, in 15 patients (45.5%). Mycophenolate mofetil (MMF) was the most frequently used steroid sparing agent, in 25 patients (75.7%). 7 patients were lost to follow up. Response was seen in 22 patients, whereas 3 patients were non responders. There was one mortality due to lower respiratory tract infection-related sepsis. Presence of sicca symptoms [91.5% vs 8.7% (p<0.001)], NSIP pattern of ILD [90% vs 10% (p = 0.002)], and absence of Raynaud's phenomenon [91.7% vs 8.3% (p<0.001)] were significantly associated with responder status when compared to non-responders.

Conclusion: ILD in primary Sjögren's syndrome is not an uncommon entity, and immunosuppression with steroids along with steroid-sparing agents led to good clinical outcomes of ILD in a majority of the patients in our cohort.