CO:08:6 | Prevalence, incidence and survival in interstitial lung disease secondary to primary Sjögren’s syndrome. Results from the “EMERGE” longitudinal study

Alessandra Rai¹, Caterina Vacchi², Stefania Cerri³, Roberta Eufrasia Ledda⁴, Giulia Cassone², Dario Andrisani³, Filippo Gozzi³, Lucia Dardani¹, Fabiola Atzeni⁵, Athina Patsoura³, Francesca Cozzini¹, Marco Sebastiani⁶, Andreina Manfredi¹. | ¹USL-IRCCS Reggio Emilia, University of Modena and Reggio Emilia; ²Azienda Ospedaliero Universitaria Policlinico di Modena; ³ Pulmonology Unit, AOU Policlinico di Modena, University of Modena and Reggio Emilia; ⁴Radiology Unit, Azienda Ospedaliera di Parma, University of Parma; ⁵ Policlinico Gaetano Martino, University of Messina; ⁶Azienda Ospedaliera di Piacenza,University of Parma, Italy

Background. Interstitial lung disease (ILD) is a severe pulmonary complication of primary Sjögren’s syndrome (pSS), but its prevalence, natural history and survival are not completely understood. Our study aimed to investigate prevalence, incidence, and impact on survival of ILD in a cohort of unselected consecutive pSS patients. We furtherly aimed to identify clinical and serological features associated with ILD, to characterize radiological findings, and to evaluate potential prognostic factors for death.

Methods. All consecutive pSS patients referred to our centre were enrolled in the study. In patients without ILD, a careful assessment for respiratory symptoms and velcro crackles was performed at enrolment and every six months. High resolution computed tomography (HRCT) was requested in case of new-onset dyspnoea, persistent dry cough, or detection of velcro crackles.

Results. We enrolled 257 pSS patients, 233 females and 24 males. Mean age at enrolment was 64.8 ± 12.6 years, with a pSS duration of 83.9±78 months. At enrolment, ILD was detected in 61/257 patients with a prevalence of 23.7%. During a mean follow-up of 42.6±14.6 months, 3 new cases of ILD were recorded, with an incidence of 0.41 new cases for 100 patients/year. In a model including sex, age at pSS diagnosis, erythro-sedimentation rate (ERS), antinuclear antibodies, sicca syndrome, and smoking habit, multivariate analysis showed a direct association between ILD and male sex, age at pSS diagnosis, and ESR>40 mmh, and an inverse correlation with sicca syndrome. A nonspecific interstitial pneumonia (NSIP) was detected in 40.6% of cases, usual interstitial pneumonia (UIP) in 31.3%, organizing pneumonia in 3.1%, lymphocytic interstitial pneumonia in 18.8%, and indeterminate patterns in 6.3%. During the follow-up, 21 patients (8.2%) died. A statistically significant difference was recorded between the overall survival of patients without (88.4%±5.5) and with ILD (66.5%±11.7) (p<0.001). The estimated mean survival time was 53.4±1.7 and 60.8±0.6 months, respectively for ILD and non-ILD groups (p<0.001). A fibrotic pattern was associated to a worse survival rate, while no difference was observed between UIP and NSIP patterns, with a survival rate of 48.0%±3.8 and 51.9%±2.3 for UIP, respectively (p=0.19), Anti-SSA antibody was a protective factor for death (HR 0.19; CI95% 0.04-0.87; p=0.03), while the age at diagnosis of pSS (HR 1.09; 1.02-1.17; p=0.01), and the extent of ILD at HRCT (HR 1.06; 1.02-1.10; p=0.001) were directly associated to an increased risk of death. Radiologic ILD pattern didn’t affect the prognosis of pSS-ILD patients.

Conclusions. In pSS, ILD can be identified in a high number of patients, and its severity significantly influences the prognosis of the disease. Of interest, radiologic ILD patterns didn’t influence the risk of death; therefore, a careful monitoring, within a multidisciplinary team, should be ensured to all pSS-ILD patients