Background: Interstitial lung disease (ILD) in primary Sjögren’s syndrome (pSS) has been reported to be present in 10-15% of patients, but pSS-ILD behavior over time is not well characterized.

Objectives: Assess the pattern of ILD in pSS, its disease behavior and factors associated with disease progression in a well-characterized pSS-ILD cohort.

Methods: All pSS patients from the Oslo University Hospital (OUH) were included if ILD was diagnosed on HRCT. Clinical characteristics, lung function tests including forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) and ILD pattern on HRCT assessed by a radiologist were evaluated. We determined ILD progression, defined as absolute FVC decline >5% or absolute DLCO decline >10% over 12 +/-6 months and increasing extent of ILD on HRCT over the observation period. Factors associated with disease progression were chosen based on expert opinion. Descriptive analyses were conducted

Results: Of 702 pSS patients followed at OUH, we identified 60 pSS patients with ILD with 33 (55%) having follow-up at 12 months ( Table 1 ). Patients with pSS-ILD were characterized by high number of males (18%) and by frequent other extra-pulmonary organ involvement (48%) ( Table 1 ). Mean time from pSS diagnosis to ILD diagnosis was 7.4 years. In 67% ILD was diagnosed after pSS, in 13% simultaneously, in 11% before pSS diagnosis and in 9% unknown. In total, 28 (47%) were diagnosed with lymphocytic interstitial pneumonia (LIP) and 32 (53%) with reticular pattern on HRCT. Over mean follow-up of 10.9 months (SD 4.2), 7/33 (21%) showed a FVC >5% decline, 9/32 (28%) a DLCO >10% decline and 12 (36%) had at least one of these defined lung function declines on standard of care treatment. Treatment was registered as ever used and by any indication. Over an observation period of 15.4 (SD 10.6) years, 27/47 (45%) showed any ILD progression on HRCT. HRCT pattern was not associated with risk of >10% DLCO decline or ILD progression on HCRT. >5% FVC decline occurred more frequently in patients with reticular pattern compared to LIP (6/17 (35%) vs 1/16 (6%), p=0.041). Factors significantly associated with ILD progression on lung function included higher baseline FVC (99% (SD16.4) vs 87% (SD14.9), p=0.032), higher DLCO (81% (SD13.1) vs 67% (SD17.4), p=0.020), increased CRP (2/10 (20%) vs 0/16 (0%), p=0.045) and presence of polyneuropathy (2/9 (22%) vs 1/17 (6%), p=0.045).

Conclusion: A substantial number of patients with pSS-ILD progressed during the time of observation. This highlights the importance of close monitoring and active consideration of treatment options in pSS-ILD. Recommendations for disease management including screening, diagnosis, disease monitoring and treatment for pulmonary involvement in pSS are lacking to date, but are highly needed.

Disclosure of Interests: Anna-Maria Hoffmann-Vold Speakers bureau: Actelion, Boehringer Ingelheim, Jansen, Lilly, Medscape, Merck Sharp & Dohme, Roche, Consultant of: Actelion, ARXX, Bayer, Boehringer Ingelheim, Jansen, Lilly, Medscape, Merck Sharp & Dohme, Roche, Grant/research support from: Boehringer Ingelheim, Håvard Fretheim Consultant of: Bayer, Grant/research support from: Jansen, Phuong Phuong Diep Speakers bureau: Boehringer Ingelheim, Karoline Lerang: None declared, Helena Andersson: None declared, Øyvind Midtvedt: None declared, Torhild Garen: None declared, Mike Durheim Speakers bureau: Boehringer Ingelheim, Consultant of: Boehringer Ingelheim and Roche, Grant/research support from: Boehringer Ingelheim and Roche, Trond M Aaløkken Speakers bureau: Boehringer Ingelheim, Øyvind Palm: None declared, Øyvind Molberg: None declared