Background:Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by multiorgan involvement. Pulmonary hypertension (PH) is an uncommon manifestation with high morbidity and mortality whose characteristics, prevalence and evolution in SLE are not completely defined.Objectives:Using data of patients from the inception cohort Registro Español de Lupus Eritematoso Sistémico (RELES), we aimed to to identify the factors associated with pulmonary hypertension (PH) in systemic lupus erythematosus (SLE).Methods:Prospective observational study on a multicenter Spanish inception cohort. Patients with SLE, diagnosed by the American College of Rheumatology (ACR) criteria, since January 2009, who had at least one transthoracic echocardiogram (TTE) performed were selected. Demographic data, diagnostic criteria, follow-ups, treatments and SLEDAI were analyzed.Results:Of 289 patients diagnosed with SLE with TTE performed, 15 (5.2%) patients were identified to have PH. Mean age was 56,9±7,7 years, of which 93,3% (14) were women and 80% (12) Caucasian. The ACR score at diagnosis was 4.66. Mean SLEDAI was 15. Only 5 patients had dyspnea at the time of diagnosis. Mean pulmonary arterial systolic pressure was 49.2±5.6 mmHg. Among the PH, 4 patients had pericarditis (26.6%), 3 (20%) valvulopathies (1 antiphospholipid syndrome), 1 patient pulmonary embolism and 1 shrinking lung. Multivariable analysis indicated that pericarditis (odds ratio (OR)=2.53), and valvulopathies (OR 8.96) were independently associated with the development of PH in SLE. Having PH was associated with older age at diagnosis (p<0.001), more dyspnea (p<0.001), higher ESR (p=0.007), more serositis (p<0.001), higher SLEDAI (p=0.011), higher SLICC (p <0.001), higher number of admissions (p=0.006) and higher mortality (p=0.003).Conclusion:PH in SLE is a serious comorbidity with high mortality. In the RELES cohort it was associated with increased disease activity, pericarditis and valvulopathies. Performing TTE in patients with SLE may favor early diagnosis and treatment.References:[1]Kim JS, Kim D, Joo YB, et al. Factors associated with development and mortality of pulmonary hypertension in systemic lupus erythematosus patients.Lupus. 2018;27(11):1769–1777.[2]Bazan IS, Mensah KA, Rudkovskaia AA, et al. Pulmonary arterial hypertension in the setting of scleroderma is different than in the setting of lupus: A review.Respir Med. 2018;134:42–46.Disclosure of Interests:Jorge Álvarez Troncoso: None declared, Ángel Robles Marhuenda: None declared, Francesca Mitjavila Villero: None declared, Francisco José García Hernández: None declared, Adela Marín Ballvé: None declared, Antoni Castro Consultant of: Actelion pharmaceuticals, GSK, MSD., Gonzalo Salvador Cervelló: None declared, Eva Fonseca: None declared, Isabel Perales Fraile: None declared, Guillermo Ruiz-Irastorza: None declared