Cox proportional hazards model of time to first exacerbation
| Patient characteristic | Hazard ratio (95% CI) | p value |
|---|---|---|
| FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; BMI, body mass index. | ||
| Age | 0.98 (0.96 to 0.998) | 0.03 |
| Female sex | 1.45 (1.07 to 1.95) | 0.02 |
| BMI (kg/m2) | 0.99 (0.95 to 1.05) | 0.94 |
| Lung function | ||
| FEV1 (% predicted) | 0.98 (0.97 to 0.995) | 0.006 |
| FVC (% predicted) | 1.01 (0.995 to 1.02) | 0.23 |
| CF related diabetes mellitus | 0.79 (0.56 to 1.11) | 0.17 |
| Courses of IV antibiotics for pulmonary exacerbation in past 24 months | ||
| 0 | – | – |
| 1 | 1.51 (1.03 to 2.21) | 0.03 |
| 2–3 | 1.64 (1.07 to 2.52) | 0.02 |
| >3 | 3.16 (1.93 to 5.17) | <0.0001 |
| <0.0001 (trend) | ||
| Bacteria in sputum at enrolment | ||
| Burkholderia cepacia complex (BC) | 0.39 (0.24 to 0.64) | 0.0002 |
| Pseudomonas aeruginosa (PA) | 0.68 (0.43 to 1.08) | 0.1 |
| Both BC and PA | 0.29 (0.14 to 0.59) | 0.0008 |
| Other | – | – |
| New bacterial species acquired in sputum during study | 1.03 (0.82 to 1.28) | 0.82 |
| Medications used chronically | ||
| Inhaled corticosteroid | 1.13 (0.86 to 1.48) | 0.39 |
| DNase | 1.28 (0.92 to 1.78) | 0.14 |
| Inhaled antibiotics | 0.92 (0.69 to 1.21) | 0.54 |
| Oral antibiotics | ||
| None | – | – |
| Azithromycin | 1.04 (0.70 to 1.55) | 0.83 |
| Other | 0.89 (0.58 to 1.37) | 0.61 |