Table 7.
Negative binomial regression analysis of relationship between exacerbation rates over the one year follow up period and sputum neutrophil number/ml at baseline.
| Single Dependent | Multiple Dependents | |||||
|---|---|---|---|---|---|---|
| Independent Variables in Model | Incidence Rate Ratio | 95% CI | p-value | Incidence Rate Ratio | 95% CI | p-value |
| Age | 1.00 | (0.98,1.01) | 0.549 | 1.00 | (0.98,1.02) | 0.911 |
| BMI | 1.00 | (0.96,1.03) | 0.815 | 1.00 | (0.97,1.03) | 0.825 |
| Concomitant ICS use | 2.13 | (1.46,3.12) | <0.001 | 1.77 | (1.21,2.58) | 0.003 |
| Current smoking status | 0.90 | (0.67,1.20) | 0.470 | 0.91 | (0.69,1.21) | 0.520 |
| Log sputum neutrophil number/ml | 1.00 | (0.95,1.06) | 0.951 | 0.99 | (0.94,1.04) | 0.724 |
| Pack years | 1.00 | (0.99,1.00) | 0.857 | 1.00 | (0.99,1.01) | 0.974 |
| FEV1 % predicted | 0.98 | (0.97,0.99) | <0.001 | 0.98 | (0.97,0.99) | <0.001 |
| Gender | 1.18 | (0.88,1.57) | 0.268 | 1.46 | (1.08,1.98) | 0.015 |
Other independent variables were included in this analysis as shown. Post-bronchodilator FEV1 was used.