Analyses of the effect of inhaled corticosteroid(ICS) use compared with bronchodilators on the rate of exacerbation over different follow-up periods using the Canadian Optimal Therapy of COPD Trial data
| Subjects n | Rate of exacerbation yr−1 | Rate ratio (95% CI) | ||
| ICS | Bronchodilators | |||
| Follow-up period | ||||
| Entire observation period | 449 | 1.39 | 1.67 | 0.83 (0.66–1.04) |
| Until discontinuation only | 449 | 1.30 | 1.69 | 0.78 (0.61–0.99) |
| After discontinuation | 137 | 2.02 | 1.64 | 1.23 (0.78–1.95) |
CI: confidence interval.