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.

With the availability of numerous PROs, it is important to understand which provide a better evaluation of patients' health status and demonstrate responses to treatment. Even when PROs evaluate the same parameter, e.g. dyspnoea, they may not always capture a uniform response. Hence, it would be useful to examine if the PROs correlate with each other and whether any specific PROs better reflect treatment benefit (as expressed by minimal clinically important differences (MCIDs)) than the others. Furthermore, understanding the relationship between the PROs and lung function (FEV1) may provide insights into whether a change in lung function translates to a change perceptible by the patients (assessed through PROs).

Tiotropium is a potent, long-acting, selective anticholinergic bronchodilator. Treatment with tiotropium produces sustained improvements in lung function, particularly FEV1 (peak, trough, average, and area under the curve) compared with either placebo or ipratropium in patients with moderate to severe COPD. Preliminary evidence suggests that treatment with tiotropium may slow the rate of decline in FEV1, but this finding awaits confirmation. Tiotropium reduces lung hyperinflation, with associated improvements in exercise capacity. Tiotropium, compared with either placebo or ipratropium, improves a variety of patient-centered outcomes, including subjective dyspnea ratings and Health Related Quality of Life (HRQL) scores. Tiotropium reduces the frequency of COPD exacerbations and of hospitalizations due to exacerbations, but has not been shown to reduce all-cause mortality. Compared with the long-acting bronchodilators, tiotropium provides incrementally better bronchodilation, but it is not clearly superior in terms of patient-centered outcomes. Tiotropium has a good safety profile; however patients with severe cardiac disease, bladder outlet obstruction, or narrow angle glaucoma were excluded from all studies.

Inclusion Criteria:

1. Adult patients (≥40 years old) with a diagnosis of Chronic Respiratory Pulmonary Disease (COPD).
2. Patients who were treated with Inhaled Corticosteroid (ICS)/LABA, LABA/LAMA with a LABA or ICS/LABA or were not receiving long-acting bronchodilators (LABA or LAMA) for COPD and required addition of tiotropium from 1 to 7 days before the start of the study.
3. Patients who are able to provide informed consent and follow study procedures and requirements.

Exclusion Criteria:

1. According to the contraindications of the product's Summary of Product Characteristics.
2. Patients receiving LAMA monotherapy prior to study entry.

Adult patients patients (≥40 years old) with a diagnosis of Chronic Respiratory Pulmonary Disease (COPD) who were treated with ICS/LABA, LABA/LAMA with a LABA or ICS/LABA or were not receiving long-acting bronchodilators (LABA or LAMA) for COPD and required addition of tiotropium from 1 to 7 days before the start of the study.