Table 1.

Baseline characteristics of subjects by sex

	Male		Female
	n	Value	n	Value
Characteristic, mean (minimum, maximum)
Age, yearsa	88	57 (19, 90)	317	53 (14, 86)
Weight, kgb	88	82 (50, 155)	317	73 (40, 129)
Baseline 6MWD, m	88	337 (168, 450)	316	346 (150, 463)
Race
White	72	82.8	254	80.4
African American or black	5	5.7	29	9.2
Asian	10	11.5	24	7.6
American Indian or Alaska Native	0	0	5	1.6
Pacific Islander	0	0	2	0.6
Other	0	0	2	0.6
PAH etiologyb
Idiopathic/familial	68	77.3	179	56.5
Collagen vascular disease	9	10.2	86	27.1
Anorexigen use	2	2.3	14	4.4
Associated with an atrial septal defect	2	2.3	30	9.5
Surgical repair of VSD or PDA ≥1 year	7	8	8	2.5
Concomitant use of bosentan	41	46.6	175	55.2
Treatment dose
Placebo	17	19.3	65	20.5
Tadalafil 2.5 mg	18	20.5	64	20.2
Tadalafil 10 mg	13	14.8	67	21.1
Tadalafil 20 mg	20	22.7	62	19.6
Tadalafil 40 mg	20	22.7	59	18.6
WHO functional class
1	1	1.1	3	0.9
2	25	28.4	105	33.1
3	60	68.2	204	64.4
4	2	2.3	5	1.6

^NoteExcept where otherwise noted, data are no. (%) of patients. 6MWD: 6-minute walk distance; PAH: pulmonary arterial hypertension; VSD: ventricular septal defect; PDA: patent ductus arteriosus; WHO: World Health Organization.

^aP = 0.01.

^bP = 0.0001.