| Unadjusted HR (95% CI) | p-value | Adjusted for underlying diagnosis and age HR (95% CI) | p-value | |
| Age per year | 0.99 (0.96–1.02) | 0.40 | NA | |
| Male versus female | 2.82 (0.82–9.63) | 0.10 | 3.04 (0.80–11.5) | 0.10 |
| CTD-PAH versus IPAH/AiPAH | 3.04 (1.02–9.05) | 0.04 | 5.66 (1.67–19.2)# | <0.01 |
| WHO FC pre-admission | 4.39 (2.02–9.53) | <0.01 | 3.58 (1.63–7.88) | <0.01 |
| Charlson index ≥2 | 3.22 (1.36–7.63) | <0.01 | 2.98 (0.11–8.01) | 0.03 |
| Use of inotropes during admission | 2.63 (1.01–6.81) | 0.05 | 2.37 (0.9–6.22) | 0.08 |
| Haematocrit per % | 1.01 (0.94–1.08) | 0.76 | 1.04 (0.96–1.12) | 0.32 |
| Systolic BP ≤100 mmHg upon admission | 1.62 (0.54–4.83) | 0.38 | 1.77 (0.58–5.44) | 0.32 |
| eGFR <60 mL·min−1/1.73 m2 upon admission | 3.58 (1.39–9.25) | <0.01 | 5.93 (1.68–20.9) | <0.01 |
| Na ≤136 mEq·mL−1 upon admission | 2.08 (0.88–4.91) | 0.09 | 1.72 (0.71–4.16) | 0.23 |
| eGFR <60 mL·min−1/1.73 m2 at discharge | 2.75 (1.07–7.1) | 0.04 | 5.84 (1.27–26.7) | 0.02 |
| Na ≤136 mEq·mL−1 at discharge | 0.82 (0.35–1.92) | 0.64 | 0.67 (0.26–1.68) | 0.39 |
HR: hazard ratio; NA: not applicable; CTD: connective tissue disease; PAH: pulmonary arterial hypertension; IPAH: idiopathic PAH; AiPAH: anorexigen-induced PAH; WHO FC: World Health Organization functional class; BP: blood pressure; eGFR: estimated glomerular filtration rate. #: adjusted only for age.