Clinical Characteristics of Primary and Overlap Sjögren's Syndrome-Associated Pulmonary Arterial Hypertension: A Multicenter Retrospective Study

Objective: To explore the clinical characteristics and risk factors for adverse outcomes in patients with Sjögren's Syndrome-associated pulmonary arterial hypertension (SS-PAH).

Methods: A retrospective analysis was conducted on SS-PAH patients diagnosed by right heart catheterization (RHC) between March 2013 and March 2024 across four Chinese medical centers. Patients were categorized into primary SS-PAH (pSS-PAH) and overlap SS-PAH, based on the presence of additional autoimmune diseases. We compared clinical and demographic data, echocardiographic and hemodynamic parameters, treatment strategies, and event-free survival between the groups. Statistical analyses included t-tests, Wilcoxon rank-sum tests, χ2 tests, Fisher's exact tests, and Kaplan-Meier survival analysis.

Results: Overlap SS-PAH was most commonly associated with systemic lupus erythematosus (SLE). Compared with pSS-PAH, overlap SS-PAH patients had a lower proportion of WHO functional class III-IV, lower pulmonary vascular resistance (PVR), and higher cardiac index (CI). They also showed higher treatment success rates and better event-free survival. However, overlap SS-PAH patients with primary biliary cholangitis (PBC) or autoimmune hepatitis (AIH) had significantly lower 1-year event-free survival rates, older age, and elevated alkaline phosphatase (ALP) levels.

Conclusion: Overlap SS-PAH generally has a better prognosis than pSS-PAH, with improved exercise capacity and milder hemodynamic abnormalities. However, overlap with PBC/AIH is associated with a poorer prognosis. These findings highlight the heterogeneity of SS-PAH and the need for tailored treatment based on underlying autoimmune conditions.

Clinical trial registration: NCT05980728, https://clinicaltrials.gov.