Baseline characteristics in placebo and bosentan groups
| Placebo | Bosentan | All | |
| Patients n | 175 | 159 | 334 |
| Sex | |||
| Female | 128 (73.1) | 125 (78.6) | 253 (75.7) |
| Male | 47 (26.9) | 34 (21.4) | 81 (24.3) |
| Age years | |||
| Mean±sd | 54.7±15.7 | 52.9±15.4 | 53.9±15.6 |
| Median (interquartile range) | 56.0 (41.0–68.0) | 55.0 (40.0–65.0) | 55.0 (40.0–66.0) |
| BMI# kg·m−2 | |||
| Mean±sd | 29.1±6.95 | 28.5±6.83 | 28.8±6.9 |
| Median (interquartile range) | 28.2 (24.5–32.8) | 27.5 (23.9–32.2) | 28.0 (24.1–32.8) |
| Geographical region | |||
| USA | 83 (47.4) | 73 (45.9) | 156 (46.7) |
| Europe | 56 (32.0) | 50 (31.4) | 106 (31.7) |
| Brazil | 35 (20.0) | 36 (22.6) | 71 (21.3) |
| Saudi Arabia | 1 (0.6) | 1 (0.3) | |
| Time from PAH diagnosis months | |||
| Mean±sd | 26.2±51.2 | 25.3±47.3 | 25.7±49.4 |
| Median (interquartile range) | 11.4 (6.0–24.9) | 12.2 (6.6–28.4) | 12.1 (6.3–26.0) |
| Aetiology of PAH | |||
| Idiopathic | 114 (65.1) | 99 (62.3) | 213 (63.8) |
| Familial | 2 (1.1) | 3 (1.9) | 5 (1.5) |
| Connective tissue disease | 45 (25.7) | 43 (27.0) | 88 (26.3) |
| Repaired congenital shunts | 11 (6.3) | 9 (5.7) | 20 (6.0) |
| Drugs and toxins | 3 (1.7) | 5 (3.1) | 8 (2.4) |
| 6-min walk distance m | |||
| Mean±sd | 357.6±73.1 | 363.1±78.5 | 360.3±75.7 |
| Median (interquartile range) | 372.0 (305–410) | 385.0 (306–423) | 375.5 (306–416) |
| WHO functional class | |||
| II | 69 (39.4) | 71 (44.7) | 140 (41.9) |
| III | 104 (59.4) | 88 (55.3) | 192 (57.5) |
| IV | 2 (1.1) | 2 (0.6) | |
| NT-proBNP¶ pmol·L−1 | |||
| Mean±sd | 170.1±239.4 | 189.7±384.0 | 179.6±317.2 |
| Median (interquartile range) | 56.6 (21.6–208.5) | 54.3 (19.4–201.0) | 54.9 (19.7–202.6) |
| Baseline sildenafil dose mg | |||
| Mean±sd | 81.1±45.1 | 77.8±48.5 | 79.6±46.7 |
| Median (interquartile range) | 60 (60–75) | 60 (60–60) | 60 (60–60) |
Data are presented as n (%) unless otherwise stated. BMI: body mass index; PAH: pulmonary arterial hypertension; WHO: World Health Organization; NT-proBNP: N-terminal pro-brain natriuretic peptide. #: placebo, n=172; bosentan, n=157. ¶: placebo, n=117; bosentan, n=110.