Clinical characteristics and survival of pulmonary arterial hypertension with or without interstitial lung disease in systemic sclerosis

Abstract

Objectives: To describe the clinical phenotype and prognosis of people in the Australian Scleroderma (SSc) Cohort Study with pulmonary arterial hypertension (PAH) with or without interstitial lung disease (ILD). Methods: Participants meeting ACR/EULAR criteria for SSc were divided into four mutually exclusive groups: those meeting criteria for PAH (PAH-only), ILD (ILD-only), concurrent PAH and ILD (PAH-ILD) or neither PAH nor ILD (SSc-only). Logistic or linear regression analyses were used for associations between clinical features, health-related quality of life (HRQoL) and physical function. Survival analysis was performed using Kaplan–Meier estimates and Cox-regression modelling. Results: Of 1561 participants, 7% fulfilled criteria for PAH-only, 24% ILD-only, 7% PAH-ILD and 62% SSc-only. People with PAH-ILD were more frequently male, with diffuse skin involvement, higher inflammatory markers, older age of SSc onset and higher frequency of extensive ILD than the cohort overall (p < 0.001). People of Asian race more frequently developed PAH-ILD (p < 0.001). People with PAH-ILD or PAH-only had worse WHO functional class and 6-min-walk-distance than ILD-only (p < 0.001). HRQoL scores were worst in those with PAH-ILD (p < 0.001). Survival was reduced in the PAH-only and PAH-ILD groups (p < 0.01). Multivariable hazard modelling demonstrated the worst prognosis in extensive ILD and PAH (HR = 5.65 95% CI 3.50–9.12 p < 0.01), followed by PAH-only (HR = 4.21 95% CI 2.89–6.13 p < 0.01) and PAH with limited ILD (HR = 2.46 95% CI 1.52–3.99 p < 0.01). Conclusions: The prevalence of concurrent PAH-ILD in the ASCS is 7%, with poorer survival in those patients with PAH-ILD compared to ILD or SSc alone. The presence of PAH confers a poorer overall prognosis than even extensive ILD; however, further data are required to better understand the clinical outcomes of this high-risk patient group.