Prevalence and factors associated with suboptimal peak inspiratory flow rates in COPD

Sohini Ghosh,1 Roy A Pleasants,2 Jill A Ohar,3 James F Donohue,1 M Bradley Drummond1 1Division of Pulmonary Diseases and Critical Medicine, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 2Durham VA Medical Center, Durham, NC, USA; 3Department of Medicine, Section of Pulmonary, Critical Care, Allergy, and Immunology, School of Medicine, Wake Forest University, Winston-Salem, NC, USA Purpose: Adequate peak inspiratory flow rate (PIFR) is required for drug dispersion with dry powder inhalers (DPIs). Prevalence of PIFR discordance (suboptimal PIFR with prescribed inhalers) and factors influencing device-specific PIFR are unclear in COPD. The objective of this study was to determine the prevalence of PIFR discordance and associated clinical factors in a stable COPD population. Patients and methods: An observational, single-center, cohort study was conducted including 66 outpatients with COPD. PIFR was measured using the In-Check™ Dial with applied resistance of prescribed inhalers. Participants were defined as discordant if measured PIFR was <30 L/min and <60 L/min for high and low–medium resistance devices, respectively, using an inspiratory effort the participant normally used with their prescribed DPI.Results: The median age of the COPD participants was 69.4 years, 92% were white and 47% were female. A total of 48% were using low–medium resistance DPIs (Diskus®/Ellipta®) and 76% used high-resistance DPI (Handihaler®). A total of 40% of COPD participants were discordant to prescribed inhalers. Female gender was the only factor consistently associated with lower PIFR. Shorter height was associated with reduced PIFR for low–medium resistance (r=0.44; P=0.01), but not high resistance (r=0.20; P=0.16). There was no correlation between PIFR by In-Check™ dial and PIFR measured by standard spirometer.Conclusion: PIFR is reduced in stable COPD pat