High Prevalence of Suboptimal Peak Inspiratory Flow in Hospitalized Patients With COPD: A Real-world Study

For optimal drug delivery, dry powder inhalers (DPIs) depend on the patient's peak inspiratory flow (PIF) and the internal resistance of the device to create turbulent energy and disaggregate the powder. A suboptimal PIF may lead to ineffective drug inhalation into the lungs. Our objective was to report the prevalence of suboptimal PIF in patients with COPD hospitalized for any reason using 1 or more DPIs. In this real-world, observational, single‑site, retrospective study, PIF was measured for each DPI using the In-Check™ DIAL set to match the resistance of the DPI used by each patient. PIFs <60 and <30L/min were considered suboptimal for low to medium-high- and high-resistance DPIs, respectively. At initial hospitalization, the prevalence of suboptimal PIF was 44.6% in 829 patients (mean age, 71.7 years; 56.8% female); 21.2% were measured during admission for a COPD exacerbation. Suboptimal PIF percentages were 61.0% (38.1±9.5L/min [mean±standard deviation (SD)]) across low to medium-high-resistance DPIs and 17.2% (20.7±4.2L/min) for high-resistance DPIs. Overall, 190/829 patients had 1 or more 30-day all-cause readmission with 253 corresponding PIF measurements. For readmissions, suboptimal PIFs were observed in 49.5% (94/190) of patients. Suboptimal PIF percentages were 65.4% (38.4±9.2L/min) for low to medium-high-resistance DPIs and 19.8% (22.4±3.3L/min) for high-resistance DPIs. As the overall prevalence of suboptimal PIFs in hospitalized patients with COPD varied according to the specific internal resistance of the DPI, these findings may have clinical implications for inhaler selection.