NPPB and pulmonary arterial hypertension: When using an average value of the four ESC/ERS risk parameters (6MWD, WHO-FC, NT-proBNP, RA area) to divide patients into three risk groups, Kaplan-Meier analysis showed significantly different survival (p = 0.001) and TTCW (p = 0.013) among PAH patients without comorbidities, but not among PAH with comorbidities (p = 0.293 and p = 0.926, respectively; Fig. 2).