Objective: To investigate the clinical characteristics and prognostic risk factors of patients with connective tissue disorders associated pulmonary arterial hypertension (CTD-PAH). Methods: In this study

81 patients with CTD-PAH admitted to the Department of Rheumatology and Immunology and the Department of Dermatology in the First Affiliated Hospital of Hebei North University from January 2011 to December 2018 were selected as the research objects

among which

there were 36 cases of systemic lupus erythematosus associated pulmonary arterial hypertension (SLE-PAH)

24 cases of systemic sclerosis associated pulmonary arterial hypertension (SSc-PAH)

and 21 cases of primary Sj?gren syndrome associated pulmonary arterial hypertension (pSS-PAH). Baseline demographic data

clinical features

transthoracic echocardiography related parameters and laboratory findings of these 81 CTD-PAH patients were collected and analyzed. Univariate and multivariate Cox regression models were used to analyze the related risk factors for survival and prognosis in patients with CTD-PAH. Results: The mean age of 81 CTD-PAH patients was (38.54±9.76) years old

57 cases (70.4%) with Raynaud’s phenomenon

and 77 cases (95.1%) of females. SLE-PAH was the most common type of CTD-PAH (44.4%)

followed by SSc-PAH (29.6%) and pSS-PAH (25.9%). Autoantibodies were mainly anti-U1 ribonucleoprotein (U1RNP) (56.8%). The onset age of SLE-PAH patients was significantly earlier than that of pSS-PAH and SSc-PAH patients (P<0.05). All the 81 patients with CTD-PAH were followed up

and no one was lost. The overall 1-

3-and 5-year survival rates were 86.2%

77.9% and 65.7%

respectively. The 1-

3-and 5-year overall survival rates of SLE-PAH patients were 94.4%

88.5% and 78.5%

those of SSc-PAH patients were 74.1%

63.9% and 47.3% respectively

and those of pSS-PAH patients were 85.7%

74.6% and 62.6% respectively. Univariate Cox analysis showed: CTD type

cardiac index (CI) <2.0 L/ (mL·m2)

combined with mild interstitial lung disease (ILD)

6-minute walking distance (6MWD) <440 m

red blood cell distribution width-coefficient of variation (RDW-CV) >15.0%

combined with hyperuricemia (HUA)

World Health Organization (WHO) cardiac function classification ofⅢtoⅣ

combined with Raynaud’s phenomenon

N-terminal pro-B-type natriuretic peptide (NT-proBNP) >1 400 ng/L and endothelin-1 (ET-1) >0.55 ng/L were related factors affecting survival and prognosis of patients with CTD-PAH (P<0.05). After adjusting for age

right atrial pressure (RAP) and mean pulmonary artery pressure (mPAP)

multivariate Cox analysis showed that the mortality in SSc-PAH patients was 3.728 times higher than that in SLE-PAH patients (P<0.05)

that of 6 MWD<440 m CTD-PAH patients was 5.629 times than that of 6MWD≥440 m patients (P<0.05)

that of RDW-CV>15.0% CTD-PAH patients was 2.785 times than that of RDW-CV≤15% patients (P<0.05)

that of patients combined with HUA was 3.978 times higher than that of non-HUA patients (P<0.05)

that of the CTD-PAH patients with ET-1 concentration>0.55 ng/L was 3.186 times higher than that of CTD-PAH patients with ET-1 concentration≤0.55 ng/L (P<0.05). Conclusion: The majority of CTD-PAH patients are female

and the main clinical manifestations are combination of Raynaud’s phenomenon

and more than half of the patients with present anti-U1RNP antibody. SLE-PAH is the most common type of CTD-PAH and SSc-PAH has the worst prognosis. CTD type

6 MWD<440 m

RDW-CV>15.0%

combined HUA and serum ET-1 level>0.55 ng/L are independent risk factors for poor prognosis in patients with CTD-PAH. Early identification of CTD-PAH patients with poor prognosis

early intervention and active and effective follow-up are helpful to improve the long-term prognosis of patients.