Serologic, clinical, and prognostic differences are observed among patients with systemic sclerosis (SSc) that is complicated by pulmonary artery hypertension (PAH) only, interstitial lung disease (ILD) only, and PAH plus ILD, according to findings from the Australian Scleroderma Cohort Study (ASCS) published in Arthritis Research & Therapy.

Among individuals with SSc, ILD and PAH are leading causes of death. Although PAH and ILD have been considered independent manifestations of SSc, because of the high prevalence of both disorders in those with SSc, interest is on the rise regarding individuals with SSc who go on to develop concurrent precapillary PAH and ILD.

The researchers sought to describe the clinical phenotype, health-related quality of life, physical function, and prognosis among individuals from the ASCS with PAH with or without ILD. The study comprised participants who fulfilled American College of Rheumatology/European League Against Rheumatism criteria for SSc.

All study participants with SSc were divided into 1 of 4 groups:

  • PAH alone (PAH-only group)
  • ILD alone (ILD-only group)
  • Concurrent PAH and ILD (PAH-ILD group)
  • Neither PAH nor ILD (SSc-only group)

A total of 1561 participants met the study criteria. Overall, 86% (1349 of 1561) of them were female. Further, 74% (1157 of 1561) of individuals had the limited cutaneous subtype of SSc (lcSSc) and 26% (404 of 1561) of participants had the diffuse cutaneous subtype of SSc (dcSSc).

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The percent and number of patients in each of the 4 groups were as follows:

  • PAH-only group: 7.2% (112 of 1561)
  • ILD-only group: 23.8% (372 of 1561)
  • PAH-ILD group: 6.9% (107 of 1561)
  • SSc-only group: 62.1% (970 of 1561)

Results of the study revealed that participants in the PAH-ILD arm were significantly more likely to be male (P =.001) and have dcSSc (P <.001), whereas individuals in the PAH-only arm were significantly more likely to have lcSSc
(P <.001).  

Participants of Asian ethnicity were significantly more likely to be in the ILD-only and the PAH-ILD groups (P <.001). Additionally, those in the PAH-only and the PAH-ILD arms were older at onset of SSc (P <.001). A longer SSc duration at study recruitment was observed in the PAH-only arm (P =.017).

Patients in the PAH-ILD and PAH-only groups exhibited significantly worse World Health Organization functional class and 6-minute walk distance compared with those in the ILD-only group (P <.001). Moreover, health-related quality of life scores were the worst among participants in the PAH-ILD arm (P <.001).

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Significantly worse survival was reported in participants with PAH and ILD than in those with SSc only (P <.001). In addition, the prognosis of participants with PAH (ie, those in the PAH-only and the PAH-ILD arms) was significantly worse compared with that of individuals in the ILD-only and SSc-only groups (P <.001).  

Per multivariable analysis of all-cause mortality, the worse prognosis was reported in those with extensive ILD and PAH (hazard ratio [HR], 5.68; 95% CI, 3.51-9.17; P <.001), followed by those with PAH alone (HR, 4.30; 95% CI, 2.95-6.27; P <.001) and those with PAH with limited ILD (HR, 2.60; 95% CI, 1.59-4.24; P <.001).

“Further data are required to better understand these high-risk groups and determine optimal treatment,” the researchers concluded.


Fairley JL, Hansen D, Ross L, et al; Australia Scleroderma Interest Group. Clinical characteristics and survival of pulmonary arterial hypertension with or without interstitial lung disease in systemic sclerosis. Arthritis Res Ther. Published online May 12, 2023. doi:10.1186/s13075-023-03059-x