Table 3– Univariate Cox proportional hazards analysis
HR (95% CI)p-value
Age at diagnosis (per decade increase)1.43 (1.11–1.86)<0.005
Sex
 Female0.61 (0.32–1.19)0.14
 Male (reference)
Lung function at baseline
 FEV1 (per 10% pred increase)1.09 (0.91–1.31)0.36
 FVC (per 10% pred increase)1.07 (0.91–1.26)0.42
DL,CO (per 10% pred increase)0.75 (0.63–0.90)<0.005
WHO FC at baseline
 I/II0.60 (0.18–2.02)0.41
 III0.63 (0.24–1.67)0.34
 IV (reference)
WHO FC on treatment
 I/II0.13 (0.04–0.43)<0.001
 III0.28 (0.09–0.89)<0.05
 IV (reference)
Aetiology
 CTDPH1.63 (0.87–3.06)0.12
 IPAH (reference)
Haemodynamics at baseline
ra (per 5 mmHg increase)1.19 (0.90–1.58)0.21
pa (per 5 mmHg increase)1.01 (0.91–1.12)0.81
 CI (per 1 L·min−1·m−2 increase)0.83 (0.49–1.39)0.47
 PVR (per 1 Wood unit increase)1.01 (0.96–1.06)0.68
SV,O2 (per 5% increase)0.93 (0.73–1.19)0.56
6MWD at baseline#
 Absolute 6MWD (per 50 m increase)0.78 (0.67–0.95)<0.005
 6MWD % pred (per 10% increase)
  Enright 110.83 (0.69–0.99)<0.05
  Troosters 130.77 (0.62–0.96)<0.05
  Gibbons 120.74 (0.61–0.90)<0.005
  Chetta 100.79 (0.66–0.94)<0.01
6MWD on treatment
 Absolute 6MWD (per 50 m increase)0.74 (0.64–0.90)<0.005
 6MWD % pred (per 10% increase)
  Enright 110.75 (0.61–0.93)<0.01
  Troosters 130.68 (0.53–0.89)<0.005
  Gibbons 120.67 (0.53–0.85)<0.005
  Chetta 100.72 (0.59–0.88)<0.005
  • HR: hazard ratio; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; DL,CO: diffusing capacity of the lung for carbon monoxide; WHO FC: World Health Organization functional class; CTDPH: connective tissue disease-associated pulmonary hypertension; IPAH: idiopathic pulmonary arterial hypertension; ra: mean right atrial pressure; pa: mean pulmonary artery pressure; CI: cardiac index; PVR: pulmonary vascular resistance; SV,O2; mixed venous saturation; 6MWD: 6-min walk distance. #: n = 130; : n = 110.