| Variable | No exacerbations | ≥1 exacerbation | Total |
| Subjects n | 436 | 415 | 851 |
| Follow-up time yrs | 4.5 (1.6–9.1) | 8.2 (3.8–9.9) | 6.7 (2.4–9.7) |
| Female | 176 (40.4) | 205 (49.4) | 381 (44.8) |
| Age yrs | 19.6 (9.6–31.1) | 16.0 (8.5–25.9) | 18.0 (8.7–28.5) |
| Age at diagnosis yrs | |||
| <1 | 209 (47.9) | 247 (60.0) | 456 (53.6) |
| <12 | 135 (31.0) | 123 (29.6) | 258 (30.3) |
| ≤18 | 22 (5.1) | 21 (5.1) | 43 (5.1) |
| >18 | 69 (15.8) | 23 (5.5) | 92 (10.8) |
| Unknown | 1 (0.2) | 1 (0.2) | 2 (0.2) |
| Genotype | |||
| Homozygous ΔF508 | 160 (36.7) | 189 (45.5) | 349 (41.0) |
| Heterozygous ΔF508 | 159 (36.5) | 137 (33.0) | 296 (34.8) |
| Other/other | 40 (9.2) | 43 (10.4) | 83 (9.8) |
| Unknown | 77 (17.6) | 46 (11.1) | 123 (14.4) |
| Pancreatic insufficiency | 324 (74.3) | 361 (87.0) | 685 (80.5) |
| Body mass index | |||
| Underweight | 23 (5.3) | 30 (7.2) | 53 (6.2) |
| Normal weight | 321 (73.6) | 346 (83.4) | 667 (78.4) |
| Overweight | 92 (21.1) | 39 (9.4) | 131 (15.4) |
| Cystic fibrosis-related diabetes mellitus | 30 (6.9) | 38 (9.1) | 68 (8.0) |
| Pseudomonas aeruginosa infection | 197 (45.2) | 270 (65.1) | 467 (54.9) |
| Burkholderia cepacia complex infection | 62 (14.2) | 71 (17.1) | 133 (15.6) |
| Allergic bronchopulmonary aspergillosis | 0 (0) | 46 (11.1) | 46 (5.4) |
| Lung Function | |||
| Average number of pulmonary function tests per yr per subject | 1 (1–2) | 2 (1–3) | 1 (1–2) |
| Baseline FEV1 % pred | 74.8±26.7 | 64.0±24.5 | 69.5±26.2 |
| Baseline FEV1 z score | -2.1±2.3 | -3.0±2.1 | -2.5±2.0 |
Data are presented as median (interquartile range), n (%) or mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; % pred: % predicted.