QualiTy of Life Evaluation in Patients With ChRonic ObstructIve Pulmonary Disease Who Require Tiotropium as additiOnal treatmeNt.

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous disease usually with a decline lung function and worsening symptoms; hence, both forced expiratory volume in 1 s (FEV1; lung function) and validated patient-reported outcomes (PROs) are used in clinical trials to assess disease severity and response to treatment. The PROs are different in terms of their scope of assessment and in the information that they capture. PRO questionnaires such as the Baseline Dyspnoea Index (BDI), Transition Dyspnoea Index (TDI) and modified Medical Research Council (mMRC) dyspnoea scale are used to assess dyspnoea, whereas the Clinical COPD Questionnaire (CCQ), COPD Assessment Test (CAT) and St George's Respiratory Questionnaire (SGRQ) are commonly used to assess patients' health status . Furthermore, the mMRC scale is unidirectional and minimally responsive to treatment interventions, while the BDI, TDI, CAT, CCQ and SGRQ (approved by the USA Food and Drug Administration) are multidirectional.