Suboptimal Peak Inspiratory Flow and Critical Inhalation Errors are Associated with Higher COPD-Related Healthcare Costs

Purpose: To assess the relationship between suboptimal Peak Inspiratory Flow (sPIF), inhalation technique errors, and non-adherence, with Healthcare Resource Utilisation (HCRU) in Chronic Obstructive Pulmonary Disease (COPD) patients receiving maintenance therapy via a Dry Powder Inhaler (DPI).Patients and methods: The cross-sectional, multi-country PIFotal study included 1434 COPD patients (>= 40 years) using a DPI for maintenance therapy. PIF was measured with the In-Check DIAL G16, and sPIF was defined as a typical PIF lower than required for the device. Inhalation technique was assessed by standardised evaluation of video recordings and grouped into 10 steps. Patients completed the "Test of Adherence to Inhalers" questionnaire. HCRU was operationalised as COPD-related costs for primary healthcare, secondary healthcare, medication, and total COPD-related costs in a 1-year period.Results: Participants with sPIF had higher medication costs compared with those with optimal PIF (cost ratio [CR]: 1.07, 95% CI [1.01, 1.14]). Multiple inhalation technique errors were associated with increased HCRU. Specifically, "insufficient inspiratory effort" with higher secondary healthcare costs (CR: 2.20, 95% CI [1.37, 3.54]) and higher total COPD-related costs (CR: 1.16, 95% CI 1.03- 1.31). "no breath-hold following the inhalation manoeuvre (<6 s)" with higher medication costs (CR: 1.08, 95% CI [1.02, 1.15]) and total COPD-related costs (CR 1.17, 95% CI [1.07, 1.28]), and "not breathing out calmly after inhalation" with higher medication costs (CR: 1.19, 95% CI [1.04, 1.37]). Non-adherence was not significantly associated with HCRU.Conclusion: sPIF and inhalation technique errors were associated with higher COPD-related healthcare utilisation and costs in COPD patients on DPI maintenance therapy.