Prevalence and predictors of suboptimal peak inspiratory flow rate in COPD patients.

The aim of this study was to determine prevalence and possible clinical predictors of suboptimal peak inspiratory flow rate (PIFR) with different dry powder inhalers. PIFR was measured across all resistance ranges of In-Check Dial® in 180 chronic obstructive pulmonary disease (COPD) subjects before hospital discharge. COPD subjects were defined as suboptimal if measured PIFR was suboptimal with any resistance representative of specific inhalers (R1-R5). Demographics and clinical data were collected, including COPD Assessment Test (CAT) and modified Medical Research Council (mMRC) scores, Global Initiative for Obstructive Lung Disease (GOLD) stage spirometry by Spirodoc® and peak flow meter measurements with portable peak inspiratory and expiratory flow meters. All were correlated with In-Check Dial PIFRs. Suboptimal PIFR was 44.44% prevalent in COPD subjects. 55% of the suboptimal cohort was female which represent 57.14% of the total female population in the study. The distribution of suboptimal PIFR included 43.75% with R1, 67.5% with R2, 100% with R3, 13.75% with R4, and 21.25% with R5. In the suboptimal cohort, CAT score was significantly higher and spirometry demonstrated significantly lower lung function results compared to the optimal cohort (p < 0.05). The only parameter to show strong and moderate correlation with In-Check Dial PIFRs was PIFR measured by peak flow meter (p < 0.001). Suboptimal PIFR is common among COPD subjects at hospital discharge. Female gender and peak flow meter PIFR was the only predictor of suboptimal PIFR. Inhaler therapy for COPD patients must be personalized based on simple routine measurement of In-Check Dial PIFRs or peak flow meter PIFR to optimize clinical benefits .