Abstract
INTRODUCTION: Current risk models for pulmonary arterial hypertension (PAH) omit anemia, although it may aggravate symptoms and haemodynamics. We assessed whether anemia and its subtypes add prognostic value. METHODS: This study included patients with idiopathic (IPAH) or connective tissue disease-associated PAH (CTD-PAH). Anemia was classified per WHO criteria into four subtypes: anemia of chronic disease (ACD), iron deficiency anemia (IDA), ACD/IDA overlap, and multifactorial anemia. Risk stratification followed the ESC 2022 guidelines and was reassessed after 12 months. RESULTS: Among 127 patients (78.7% IPAH, 21.3% CTD-PAH) anemia was present in 22 patients (17.3%), including ACD (31.8%), ACD/IDA overlap (27.3%), and multifactorial anemia (40.9%). Patients with anemia had higher baseline risk strata, worse functional status, elevated NT-proBNP levels (p = 0.002), and shorter six-minute walk distances (p = 0.007). Anemia reduced the odds of clinical improvement by 75% (OR, 0.25; p = 0.02). Over a follow-up of 57.8 months, 64 patients (50%) died. ACD (HR, 2.43; 95% CI, 1.03-5.7; p = 0.04) and ACD/IDA (HR, 2.14; 95% CI, 1.04-4.41; p = 0.04) independently predicted mortality, even after adjustment for age and risk. CONCLUSION: Anemia, particularly ACD and ACD/IDA, independently predicts a lower probability of achieving therapeutic goals within 12 months and is associated with higher long-term mortality, even after adjustment for the ESC/ERS 2022 recommended risk stratification.