ObjectiveIncorrect inhaler use and poor treatment adherence have a negative impact on COPD outcomes. This multi-centre, single arm, non-interventional, phase IV study investigated whether inhalation technique, treatment adherence and patient outcomes change in patients who evolve from dual therapy or multiple inhaler triple therapy to single inhaler extrafine triple therapy (beclomethasone dipropionate (BDP, 87 μg), formoterol fumarate (FF, 5 μg) and glycopyrronium (G, 9 μg)) in combination with inhalation technique training. MethodsA total of 126 COPD patients were included in the per protocol set. Inhalation technique and treatment adherence were assessed at baseline and at two visits at approximately 3 and 6 months of treatment with extrafine BDP/FF/G. In addition, lung function, symptom score, patient satisfaction and exacerbations (exploratory) were followed up. ResultsBefore switching to single inhaler extrafine BDP/FF/G (baseline), any device errors and critical errors were detected for 28.8% and 9.6% of patients, respectively. After switching to BDP/FF/G, the percentage of patients with any device errors decreased to 14.0% (visit 2) and 16.3% (visit 3), without critical errors at the two follow-up visits. Treatment adherence increased from 67.5% at baseline to 75.8% (visit 2) and 80% (visit 3). In addition, lung function, symptom and patient satisfaction scores improved, whilst exacerbation rates substantially decreased. ConclusionsThis observational study demonstrates that in eligible COPD patients in a real-life setting, the switch from dual therapy or multiple inhaler triple therapy to single inhaler extrafine BDP/FF/G in combination with inhalation technique training is associated with improved inhalation technique and adherence.