Table 2 Hazard ratios of determinants of developing a next exacerbation after oral corticosteroids with antibiotics—compared with oral corticosteroids only—treatment in a multivariable Cox model
HR of new exacerbation99% CI for hazard ratio
Antibiotics added to treatment with oral corticosteroids
    0–3 months following treatment0.620.600.65
    3–6 months following treatment0.680.650.73
    6–12 months following treatment1.030.961.12
    >12 months following treatment1.311.181.45
Exposure to antibiotics after previous exacerbation0.820.780.87
Female sex0.950.911.00
Inhaled corticosteroids as maintenance medication0.910.840.98
Co-medication cardiovascular1.161.101.23
Co-medication for diabetes1.050.981.12
Hospitalisation* for COPD†1.451.351.57
Hospitalisation for pneumonia1.191.051.34
  • The variables “age” and “number of respiratory drugs dispensings in 2003” were included in the Cox model, but were not fitted linearly, and therefore HR are not presented.

  • *Once or more in previous 2 years. †Diagnosis: chronic bronchitis, emphysema or COPD.

  • COPD, chronic obstructive pulmonary disease; HR, hazard ratio.