Clinical Research Directory

Inclusion Criteria: * Definite diagnosis of CTD included Systemic lupus erythematosus（SLE） diagnosed according to the 2019 The European Alliance of Associations for Rheumatology（EULAR） criteria, primary Sjogren's syndrome (pSS) defined according to the 2016 American College of Rheumatology(ACR) criteria, Systemic Sclerosis(SSc) defined according to the 2013 ACR criteria, mixed connective tissue disease (MCTD) defined by Sharp criteria, and Rheumatoid Arthritis(RA) defined according 2010 ACR criteria of two or more CTD at the same time were defined as having overlap syndrome (OS). Patients who had clinical and serological manifestations suggestive of systemic autoimmune diseases but did not fulfil the classification criteria for CTD were defined as having undifferentiated CTD (UCTD). * PAH was diagnosed by right heart catheterization was defined as mean Pulmonary Artery Pressure (mPAP)\>20 Millimeters of mercury（mmHg）, Pulmonary Artery Wedge Pressure（PAWP）≤15mmHg, Pulmonary Vascular Resistance（PVR）\>2 Wood Exclusion Criteria: * significant interstitial lung disease or chronic obstructive pulmonary disease; * left heart disease or congenital heart disease associated with pulmonary hypertension; * chronic thromboembolic pulmonary hypertension; * portal hypertension; * drug or toxin exposure; * HIV infection; * any other diseases known to be associated with PAH; * age\<18 years.