Prevalence, Incidence of PAH in SSc Steady Over Time, Report Says

The authors said this study included more up-to-date definitions of diagnosing pulmonary arterial hypertension (PAH), which is an increasing factor in deaths from systemic sclerosis (SSc).

A recent systematic review and meta-analysis examined the prevalence and incidence of pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc).

PAH and interstitial lung disease have become an increasing factor in deaths among patients with SSc as other mortality causes, such as from scleroderma renal crisis, have dropped. The authors said some studies have attempted to pinpoint the prevalence and incidence of PAH but those studies were based on echocardiographic findings, which they said does not represent the gold standard for a PAH diagnosis.

In this study, the authors said they applied newer recommendations for diagnosing PAH, and as a result, they said their results show the “largest and most accurate metanalysis focused on the prevalence and incidence of SSc-related PAH.

The study, published in Autoimmunity Reviews, examined databases from June 1962 to May 2019. The researchers wrote that the criteria for a PAH diagnosis were mean pulmonary arterial pressure >25 mm Hg plus pulmonary capillary wedge pressure <15 mm Hg.

When available and reported in previous studies, they also included data on pulmonary vascular resistance >3 WU, which is now part of the current definition of PAH.

The first pass found 2115 articles; of those, 1972 articles were not included. Of the 143 articles selected for full-text review, 24 were eventually selected for the global prevalence meta-analysis and 15 were selected for the incidence meta-analysis.

The global prevalence review contained data on 9804 patients with SSc. The overall PAH prevalence was determined to be 6.4% (95% CI, 5%-8.3%).

The study also examined the prevalence of PAH in limited cutaneous systemic sclerosis (lcSSc), with 14 studies containing data on 4987 patients. The PAH prevalence found in lcSSc was 7.7% (95% CI, 5.3%-11.1%).

Twelve studies were included in the PAH prevalence study for diffuse cutaneous systemic sclerosis (dcSSc), with data on 1790 dcSSc patients. The PAH prevalence found in dcSSc was 6.3% (95% CI, 4.5%-8.9%).

Fifteen studies, involving data from 5926 patients with SSc, looked at the PAH incidence of an entire SSc cohort. The overall PAH incidence was 18.2 cases per 1000 person-years (95% CI, 12-27.4).

Looking again only at lcSSc, 8 studies with data on 2721 patients were reviewed for PAH incidence, which was determined to be 20.4 cases per 1000 person-years (95% CI, 10.1-41.1).

And 7 studies, with 942 patients with dcSSc, were analyzed for PAH incidence, showing an overall PAH incidence in dcSSc of 16.6 cases per 1000 person-years (95% CI, 8.5-32.1).

Overall prevalence and incidence in PAH was stable over time, the researchers reported, but they also found a trend towards declining PAH prevalence and incidence in patients with lcSSc and increasing PAH prevalence and incidence rate in dcSSc.


Rubio-Rivas M, Homs NA, Cuartero D, Corbella X. The prevalence and incidence rate of pulmonary arterial hypertension in systemic sclerosis: systematic review and meta-analysis. Autoimmun Rev. 2021;20(1):102713. doi:10.1016/j.autrev.2020.102713