Background: Effectiveness of maintenance therapy for COPD with Dry Powder Inhalers (DPIs) requires an optimal Peak Inspiratory Flow Rate (PIFR), a proper inhalation technique and adequate medication adherence from patients. Recent studies have suggested that patients with reduced peak inspiratory flow may have worse COPD-related symptom burden and increased risk of COPD-related hospitalizations. However, in primary care, little is known about how many COPD patients have suboptimal PIFR. Furthermore, there is a paucity of knowledge concerning the associations of PIFR, inhalation technique and medication adherence with the effectiveness of maintenance therapy.

Objective: To examine associations of PIFR, inhalation technique, and medication adherence with health status and disease, exacerbations, and healthcare resource utilization in patients with COPD receiving maintenance treatment with dry powder inhalers.

Study design: Cross-sectional observational study in five European countries*.

Study population: COPD patients aged 40 years or older who have received COPD maintenance therapy through DPIs in the past 3 months or longer.

Main study parameters: Health status as measured with the Clinical COPD Questionnaire (CCQ), COPD Assessment Test (CAT), number of exacerbations, an assessment of PIFR, inhalation technique errors, medication adherence, healthcare resource utilization (HCRU), medication use and demographic and clinical covariates.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: No significant burden from participating is expected. Risk of participating is deemed negligible. In addition, patients may benefit from participating. Specifically, patients who manifest inhalation errors, will receive a tailored inhalation instruction to remediate their inhalation errors. The impact of this instruction will not be evaluated in any way, therefore it should not be seen as an intervention.

* If the preplanned number of patients cannot be included also because of national outbreaks of SARS-COV-2 resulting in travel restrictions, participation will be sought from researchers from three other European countries

Inclusion Criteria:

• A clinical diagnosis of COPD;
• Age ≥ 40;
• Use of maintenance therapy through a DPI in the last 3 months or longer
• Sufficient investigator-assessed decision-making capacity to provide informed consent (patients will not be invited if they have acute psychotic disorders, severe pervasive developmental disorders / severe intellectual disability or advanced neurodegenerative disease)

Exclusion Criteria:

• An exacerbation in the past 6 weeks (as this requires a patient to recover)
• Life threatening disease and life expectancy < 6 months (as inclusion of these patients is unethical)
• Participation in a randomized clinical trial on COPD medication

COPD patients aged forty years and older and who are treated with DPIs as a maintenance therapy