Abstract Background: Pulmonary arterial hypertension (PAH) is a chronic disease with high morbidity and mortality. The diagnosis of PAH is mainly made based on echocardiographic parameters and natriuretic peptide levels. However, given the low incidence of PAH worldwide, the diagnosis of PAH can be challenging. Objectives: To evaluate the relationship between systemic immune-inflammation (SII) index and PAH. Methods: This was a retrospective, cross-sectional study of 110 patients (43 PAH patients and 67 controls). The SII index was compared between the […]