Pulmonary Arterial Hypertension Incidence in Scleroderma Patients Treated with Bosentan for Digital Ulcers: Evidence from the Italian SPRING Registry.

Objective: Bosentan (BOS) is approved for treating pulmonary arterial hypertension (PAH) and preventing digital ulcers (DU) in systemic sclerosis (SSc). Our study aimed to evaluate whether BOS prescribed for DU could reduce the incidence of PAH in a large SSc cohort from the SPRING registry.

Methods: Patients with SSc from the SPRING registry, meeting ACR/EULAR 2013 classification criteria with data on PAH onset, DU status, BOS exposure, and at least a one-year follow-up between 2015 and 2020, and no known PAH at baseline were included. PAH was diagnosed with right heart catheterization during the follow-up, and its incidence rate (IR) was calculated. Kaplan-Meier curves were determined, and multivariate regression identified PAH risk factors.

Results: Among 727 eligible patients with SSc, followed for a median of 2.0 years, 54 (7.4%) developed PAH [IR 3.71 per 100 patients/years]. Patients with DU who were never exposed to BOS had a higher incidence of PAH [IR 4.90 per 100 patients/years] compared to those exposed to BOS, whose rates matched those without DU and who were never exposed to BOS. Risk factors independently associated with PAH development included DU (HR 1.85), age (HR 1.05), modified Rodnan Skin Score (mRSS) >4 (HR 2.07), ILD (HR 2.29), and acetylsalicylic acid treatment (HR 1.78).

Conclusion: In our cohort, DU were confirmed as a leading risk factor for PAH development, and BOS use for DU prevention may reduce this risk. Only patients with DU who were not on BOS had an increased PAH incidence.