Risk Assessment Models and Event-Free Survival in Pulmonary Arterial Hypertension

Evidence on the predictive ability of risk assessment models for event-free survival (EFS) in patients with pulmonary arterial hypertension is scarce. We aimed to investigate the relationship between risk status at 6 months after diagnosis (6 M) and EFS, by three risk models: Multicomponent Improvement (MCI), ESC/ERS 4-Strata Risk (4SR), and noninvasive French PH Registry Score (FRS). Data collected in the Swedish PAH Registry 2008-2021 were used. The study population was risk-stratified at 6 M according to each model. Information on PAH-related hospitalization (HOSP) was collected from the National Patient Register. EFS was defined as survival without occurrence of: (1) HOSP; (2) initiation of parenteral prostacyclin therapy or dose increase ≥ 10%; (3) lung transplantation. The association between risk and EFS was evaluated by Kaplan-Meier estimates and Cox proportional models. The analysis included 411 incident patients, median age 66 y [50, 73]. Median survival time was 3.5 y [1.7; 5.4], and cumulative EFS was 55%. In a Cox proportional regression adjusted for age, eGFR, obesity, atrial fibrillation, and systemic hypertension, EFS was higher in patients who: (1) achieved two or three MCI criteria compared to one or no MCI criterion (HR 0.58; CI 0.39-0.84, p = 0.005); (2) were assessed as low, intermediate-low, or intermediate-high compared to high risk (HR 0.16; CI 0.09-0.28, p < 0.001); or (3) fulfilled one, two, or three low-risk FRS criteria, compared to no low-risk criterion (HR 0.29; CI 0.19-0.43, p < 0.001). Performing a risk assessment 6 months after diagnosis effectively predicts the likelihood of EFS in the studied population, highlighting its prognostic value.