Survival and predictors of mortality in systemic sclerosis-associated pulmonary arterial hypertension: outcomes from the pulmonary hypertension assessment and recognition of outcomes in scleroderma registry

Abstract

Objective: To assess cumulative survival rates and identify independent predictors of mortality in patients with incident systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) who had undergone routine screening for PAH at SSc centers in the US.

Methods: The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma registry is a prospective registry of SSc patients at high risk for PAH or with definite pulmonary hypertension diagnosed by right-sided heart catheterization within 6 months of enrollment. Only patients with World Health Organization group I PAH (mean pulmonary artery pressure >25 mm Hg and pulmonary capillary wedge pressure <15 mm Hg without significant interstitial lung disease) were included in these analyses.

Results: In total, 131 SSc patients with incident PAH were followed for a mean ± SD of 2.0 ± 1.4 years. The 1-, 2-, and 3-year cumulative survival rates were 93%, 88%, and 75%, respectively. On multivariate analysis, age >60 years (hazard ratio [HR] 3.0, 95% confidence interval [95% CI] 1.1- 8.4), male sex (HR 3.9, 95% CI 1.1-13.9), functional class (FC) IV status (HR 6.5, 95% CI 1.8 -22.8), and diffusing capacity for carbon monoxide (DLCO) <39% predicted (HR 4.2, 95% CI 1.3-13.8) were significant predictors of mortality.

Conclusion: This is the largest study describing survival in patients with incident SSc-associated PAH followed up at multiple SSc centers in the US who had undergone routine screening for PAH. The survival rates were better than those reported in other recently described SSc-associated PAH cohorts. Severely reduced DLCO and FC IV status at the time of PAH diagnosis portended a poor prognosis in these patients.

Figure 1.

Survival in patients with systemic sclerosis (SSc)–associated pulmonary arterial hypertension (PAH) in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma registry. The 1-, 2-, and 3-year survival rates in the 131 patients with SSc-associated PAH were 93%, 88%, and 75%, respectively (A). New York Heart Association functional class (FC) IV status (B) and diffusing capacity for carbon monoxide (DLco) ≤38.9% predicted (C) were associated with poorer survival.