Preliminary baseline characteristics
| COUGH-1 | COUGH-2 | |
| Subjects in population n | 730 | 1314 |
| Sex n (%) | ||
| Male | 188 (25.8) | 339 (25.1) |
| Female | 542 (74.2) | 984 (74.9) |
| Age years | ||
| <65 n (%) | 446 (61.1) | 881 (67.0) |
| ≥65 n (%) | 284 (38.9) | 433 (33.0) |
| Mean | 59.0 | 58.1 |
| sd | 12.6 | 12.1 |
| Median | 61.0 | 60.0 |
| Range | 19–89 | 19–88 |
| Race n (%) | ||
| American Indian or Alaska Native | 21 (2.9) | 73 (5.6) |
| Asian | 104 (14.2) | 44 (3.3) |
| Black or African American | 11 (1.5) | 28 (2.1) |
| Multiple | 24 (3.3) | 103 (7.8) |
| White | 570 (78.1) | 1057 (80.4) |
| Body mass index kg·m-2 | ||
| Subjects with data | 730 | 1309 |
| Mean | 28.24 | 28.78 |
| sd | 5.75 | 5.84 |
| Median | 27.60 | 27.86 |
| Range | 16–54 | 13–56 |
| Duration of chronic cough years | ||
| Subjects with data | 730 | 1288 |
| Mean | 11.54 | 11.06 |
| sd | 9.45 | 9.84 |
| Median | 9.00 | 8.00 |
| Range | 2–59 | 1–75 |
| Region n (%) | ||
| Asia Pacific | 103 (14.1) | 81 (6.2) |
| Europe | 365 (50.0) | 714 (54.3) |
| North America | 167 (22.9) | 298 (22.4) |
| Others | 95 (13.0) | 224 (17.0) |
| Primary diagnosis n (%) | ||
| Refractory chronic cough | 430 (58.9) | 851 (64.8) |
| Unexplained chronic cough | 300 (41.1) | 459 (34.9) |
| Missing | 0 | 4 (0.3) |
| Most common comorbid conditions n (%) | ||
| Asthma | 312 (42.7) | 532 (40.5) |
| Allergic rhinitis | 145 (19.9) | 191 (14.5) |
| Gastroesophageal reflux disease | 294 (40.3) | 530 (40.3) |