Intervention

The control group receives usual treatment without systematic psychosocial risk screening. Control-arm participants receive standard-of-care pulmonary vasodilator therapy alone, and sotatercept initiation is not allowed. Sotatercept is excluded from the study definition of vasodilator-based PAH therapy. Vasodilator-based PAH therapy includes endothelin-receptor antagonists, phosphodiesterase-5 inhibitors or riociguat, and prostacyclin-class agents. Participants in the sotatercept arm receive subcutaneous sotatercept every 3 weeks alongside stable vasodilator-based PAH therapy. The initial sotatercept dose is 0.3 mg/kg, with escalation to 0.7 mg/kg from visit 2 onward if safety criteria are met. A positive psychosomatic screening prompts the patient to be offered psychosomatic consultation if they are willing. Recommended interventions include improving physical and financial access, ensuring medicine availability and staffing, reducing waiting and language barriers, and building trust through consistent effective care. Educational campaigns should engage local illness explanations and strengthen recognition of severe diarrhoeal symptoms. Interventions for diarrhoeal care-seeking s…