Clinical characteristics and survival of pulmonary arterial hypertension associated with three major connective tissue diseases: A cohort study in China

Abstract

Objective: Pulmonary arterial hypertension (PAH) is a major cause of death in connective tissue disease patients. This study investigated the clinical characteristics and survival of CTD-PAH in Chinese patients.

Methods: This cohort study enrolled 190 consecutive PAH patients with systemic lupus erythematosus (SLE), systemic sclerosis (SSc), or primary Sjögren's syndrome (pSS) who visited our referral center between May 2006 and December 2014. Baseline demographics, clinical features, laboratory results, and hemodynamic assessments were analyzed. Cox proportional hazards regression analysis was used to identify independent factors associated with increased risk of mortality.

Results: The PAH patients were more likely to have SLE (58.4%) as the underlying CTD than SSc (26.3%) or pSS (15.3%). Mean age was 37.8±10.4years, and patients with SLE were youngest at the time of PAH diagnosis. The most prevalent autoantibody was anti-U1RNP antibody (55.8%). The three groups did not differ significantly regarding World Health Organization functional class or hemodynamic results. The overall 1-, 3-, and 5-year survival rates were 87.1%, 79.1%, and 62.9%, respectively. The 3-year survival rate of 81.3% for those with SLE-PAH was significantly better than that for patients with SSc-PAH (63.6%, P<0.05). Independent predictors of mortality were 6-minute walk distance (6MWD) ≤380m (HR 3.222, 95% CI 1.485-6.987, P=0.003) and underlying CTD (HR 1.684; 95CI% 1.082-2.622, P=0.021).

Conclusion: Independent predictors of mortality for CTD-PAH were 6MWD <380m and SSc as the underlying CTD. Increased awareness of pSS-PAH is needed because of its worse prognosis compared to SLE-PAH.

Keywords: Primary Sjögren's syndrome; Pulmonary arterial hypertension; Systemic lupus erythematosus; Systemic sclerosis.