Mean rate of COPD exacerbations requiring rescue medication of 3 or more puffs/day on at least 2 consecutive days (=mild COPD exacerbations), or requiring oral or parenteral glucocorticosteroids (=moderate COPD exacerbations), or requiring hospitalization, or leading to death (=severe COPD exacerbations), per patient per year.

A COPD exacerbation is an event in the natural course of the disease characterized by a change in the patient's baseline dyspnea, cough and/or sputum beyond day-to-day variability sufficient to warrant a change in management [ATS / ERS 2005].

The TDI is a recognized questionnaire to measure dyspnea in an out patient COPD population. At baseline, 3 components of dyspnea, each graded with 4 questions, were asked:

• Functional Impairment
• Magnitude of Task
• Magnitude of Effort

At each of the post-randomization visits questions from the TDI were asked related to 3 components:

Change in

• Functional Impairment
• Magnitude of Task
• Magnitude of Effort

Each question in the TDI is graded from -3 (major deterioration) to +3 (major improvement). This results in a TDI Focal Score ranging from -9 to +9.

Mean change from baseline during the treatment period in SOBQ. This is a 24-item measure that assesses self-reported shortness of breath while performing a variety of activities of daily living.

The questions were administered at visits V0, V2, V3, V4, V5, V6 and Vend to assess the perceived shortness of breath of the patient.

For each activity listed in the questionnaire the patient should rate his/her breathlessness on a scale between zero and five, where zero is "not at all breathless" and five is "maximally breathless or too breathless to do the activity".