Peak Inspiratory Flow and Inhaler Prescription Strategies in a Specialized COPD Clinical Program: A Real-World Observational Study

Abstract

BackgroundCOPD inhaler regimens should be appropriate for the patient’s peak inspiratory flow (PIF) and should ideally consist of single or similar device(s). Research QuestionsIn a subspecialized COPD clinic: 1What is the prevalence of patients with suboptimal PIF and with inappropriate device(s) for measured PIF? 2Are there patient-related risk factors associated with suboptimal PIF? 3What is the prevalence of patients with non-single inhaler therapy (SIT)/non-similar devices? 4Does point-of-care PIF affect clinical decision-making? Study Design and MethodsIn this single-center real-world observational study, PIF was measured systematically at every outpatient visit in a subspecialized COPD clinic and point-of-care results were provided to the clinician. Co-primary outcomes were the prevalence of outpatients with suboptimal PIF and with inappropriate devices for measured PIF. Secondary outcomes were patient-related risk factors associated with suboptimal PIF, the prevalence of non-SIT/non-similar devices, the prevalence of regimens consisting of either inappropriate device(s) for measured PIF and/or non-SIT/non-similar devices, and the effect of point-of-care PIF on clinical decision-making. ResultsSuboptimal PIF was identified in 45 of 161 participants (28%) and inappropriate device(s) for measured PIF were identified in 18 (11.2%) participants. Significant associations were observed between suboptimal PIF and age (1.09 [1.04,1.15]), female sex (10.30 [4.45,27.10]), height (0.92 [0.88,0.96]), BMI (0.90 [0.84,0.96]) and FEV1 (0.09 [0.03,0.26]). Following adjustment for age and sex, the association between suboptimal PIF and BMI, but not height, remained significant. Non-SIT and/or non-similar devices were identified in 50 (31.1%) participants. Regimens consisting of either inappropriate device(s) for measured PIF and/or non-SIT/non-similar devices were observed in fifty-nine (36.6%) participants. Inhaler prescription changes were observed in this latter group (3.39 [1.76,6.64]), as well as in patients with suboptimal PIF already on SIT/similar regimens (2.93 [1.07,7.92]). InterpretationSuboptimal PIF and inappropriate devices for measured PIF are highly prevalent in outpatients from a subspecialized COPD clinic. Female sex, reduced FEV1 and low BMI are important, readily identifiable risk factors for suboptimal PIF and point-of-care PIF can inform clinical decision-making.