Table 1.

Characteristics of the study participants^*

	CTD-associated PAH			Idiopathic PAH (n = 1,654)	P, all CTD-associated PAH vs. idiopathic PAH
	All (n = 716)	SSc-associated PAH (n = 407)	Non–SSc-associated PAH (n = 309)
Age, years	53 ± 14	59 ± 11	45 ± 14	46 ± 15	<0.001
Female sex, %	89	88	90	73	<0.001
Race, %					0.39
White	71	88	49	73
Black	5	4	6	4
Other	25	8	45	23
Body mass index, kg/m2	26 ± 6	27 ± 6	26 ± 6	28 ± 7	<0.001
WHO functional class, %					0.18
I–II	47	37	59	44
III–IV	53	63	41	56
Baseline hemodynamics
Right atrial pressure, mm Hg	8.0 ± 5.0	8.3 ± 4.9	7.7 ± 5.0	9.6 ± 5.8	<0.001
Mean pulmonary arterial pressure, mm Hg	46 ± 12	45 ± 13	48 ± 12	56 ± 16	<0.001
Cardiac index, liters/minute/m2	2.5 ± 0.8	2.5 ± 0.8	2.5 ± 0.8	2.3 ± 0.8	<0.001
Pulmonary capillary wedge pressure, mm Hg	9 ± 4	10 ± 3	9 ± 3	9 ± 4	0.70
Pulmonary vascular resistance, Wood units	10.2 ± 6.2	9.6 ± 6.4	10.9 ± 5.9	13.3 ± 7.8	<0.001
Baseline 6-minute walk distance, meters	336 ± 93	322 ± 92	353 ± 91	347 ± 89	<0.001
Drug class, %					0.021
Endothelin receptor antagonists	71	72	69	67
Phosphodiesterase 5 inhibitors	12	13	11	13
Prostacyclin analogs	17	16	20	22

^*Except where indicated otherwise, values are the mean ± SD.

CTD-associated PAH = connective tissue disease–associated pulmonary arterial hypertension; SSc = systemic sclerosis; WHO = World Health Organization.