Study outcomes and definitions

  •  1) Time to first exacerbation

  •   Respiratory-related hospital attendance/admission AND/OR

  •   Respiratory-related emergency room attendance AND/OR

  •   Prescription of acute OCS course AND/OR

  •   Antibiotics prescribed with evidence of lower respiratory consultation on the same day

  •  2) Time to first acute respiratory event

  •   Respiratory-related consultation, not for annual monitoring review

  •  3) Time to treatment failure

  •   Prescription of additional chronic therapy (theophylline or other methylxanthines); maintenance OCS; PDE4 inhibitor; macrolides (e.g. azithromycin, erythromycin); mucolytics (e.g. carbocysteine, N-acetylcysteine); LTRA (nedocromil) AND/OR

  •   An exacerbation (as defined above)

  •  4) Time to first acute OCS course

  •  5) Time to first antibiotics prescription with evidence of lower respiratory consultation, to avoid misclassification of antibiotics being prescribed for another reason [18]

  •  Number of occurrences in the first 1-year outcome period of:

  •    6) Exacerbations

  •    7) Acute OCS courses

  •    8) Antibiotic prescriptions with evidence of lower respiratory consultation

  •    9) Acute respiratory events

  •  10) mMRC score within 18 months after index date; ≥2 versus <2

  •  11) Time to first pneumonia diagnosis

  •     Chest radiography AND/OR

  •     Diagnostic code

OCS: oral corticosteroid; PDE: phosphodiesterase; LTRA: leukotriene receptor antagonist; mMRC: modified Medical Research Council dyspnoea scale.