AB0597 PULMONARY FUNCTION IN PATIENTS DIAGNOSED OF EARLY SYSTEMIC SCLEROSIS: A NEW TOOL FOR SYSTEMIC SCLEROSIS CLASIFFICATION?
Authors: F. M. Ortiz Sanjuan, C. Pávez Perales, E. Vicens Bernabeu, C. Alcañiz Escandell, I. Cánovas Olmos, I. Chalmeta Verdejo, M. De la Rubia Navarro, R. Gonzalez Mazario, L. Gonzalez Puig, E. Grau García, J. Ivorra Cortés, S. Leal Rodriguez, I. Martínez Cordellat, C. Nájera Herranz, R. Negueroles Albuixech, J. E. Oller Rodríguez, J. A. Román Ivorra
Journal: Annals of the Rheumatic Diseases (2020)

Background: Interstitial lung disease (ILD) is a frequent complication of systemic sclerosis (SSc) and is often progressive and has a poor prognosis. A restrictive ventilatory defect could suggest ILD either alone or in combination with pulmonary arterial hypertension. Nowadays, Early-SSc is well defined as preliminary stage of SSc. Patients who meet criteria for Early-SSc could benefit from an early diagnosis of pulmonary involvement. Objectives: Our aim was to assess the pulmonary function in patients diagnosed of Early SSc. Methods: Retrospective observational study of a wide and unselected series of patients diagnosed as Early-SSc from a single university hospital from 2012 to 2019. Patients were classified as Early-SSc following Le Roy criteria. Despite this, patients already did not meet 2013 ACR/EULAR classification criteria for SSc. We reviewed pulmonary function through conventional spirometry and diffusing capacity of lung for carbon monoxide (DLCO). Results: We included 56 patients with a mean age of 52.3±12.1 years (96.4% women; 3.6% men). At the diagnosis of Early-SSc, no one of our patients evidenced a restrictive ventilatory pattern. DLCO was below normal limits in 18 patients (32.1%). Small airway obstruction expressed according decreased maximal (mid-) expiratory flow (MMEF) 25-75 was present in 24 patients (42.8%). After a mean follow-up period of 38.3±2.4 months, 29 (51.8%) patients fulfilled 2013 ACR/EULAR criteria. The average time between diagnosis of Early-SSc and achieve SSc classification was 24.4±1.8 months. The remaining 27 patients continued classified as Early-SSc. An analysis of the subgroup of patients which progressed to SSc showed that DLCO was decreased in 15 of those 29 patients (51.7%) and 18 of 29 patients (62.1%) presented decreased MMEF 25-75. Comparing with the subgroup of patients which not progressed to SSc were significant differences (Decreased DLCO: 51.7% vs 11.1%; p=0.02 and decreased MMEF 25-75: 42.8% vs 22.2%; p=0.05). The analysis of pulmonary function of the subgroup of patients continued classified as Early-SSc after follow-up period did not show significative changes after follow-up. Conclusion: In our study, a third of the patients classified as Early-SSc presented at diagnosis abnormal values of DLCO and/or signs of small airway obstruction without the presence of a restrictive ventilatory pattern. Moreover, this pulmonary disfunction was significantly more frequent in patients who progressed to definitive SSc. Patients which remains classified as Early-SSc did not experience significative changes. Our results support the concept that pulmonary function was impaired in Early-SSc and that I should probably be considered for future Early-SSc classification criteria. Disclosure of Interests: None declared