Prospective Evaluation of Exacerbations Associated with Suboptimal Peak Inspiratory Flow Among Stable Outpatients with COPD

Abstract

Purpose A suboptimal peak inspiratory flow (PIF) against a dry powder inhaler (DPI) may result in ineffective inhalation of medications, which may affect outcomes. The primary objective of this study was to examine the association between PIF status and COPD exacerbations among outpatients with moderate to very severe COPD. Patients and Methods This was a prospective, observational study of patients from 7 US outpatient centers. PIF was measured using an inspiratory flow meter (In-Check™ DIAL G16) set to medium low resistance. Patients were classified by suboptimal (<60 L/min) or optimal PIF (≥60 L/min). The primary outcome was the proportion of patients with moderate/severe COPD exacerbations collected by medical record review over 12 months. Secondary outcomes were time to first exacerbation and mortality. Results Of 474 patients screened, 38.8% had suboptimal PIF, and 71 patients with optimal PIF were excluded from the study. The enrolled sample included 184 and 219 patients with suboptimal and optimal PIF, respectively. Suboptimal PIF was associated with shorter stature (66.6±4.1 vs 67.8±3.8 inches, P = 0.002), female sex (45.1 vs 34.7%, P = 0.033), Black race (27.2 vs 11.0%, P < 0.001), and greater symptom burden (CAT: 22.3±7.7 vs 19.0±7.0, P < 0.001; mMRC: 2.0±1.1 vs 1.7±1.1, P = 0.003). The proportion of patients with COPD exacerbations at 12 months was not significantly different (29.3 vs 27.9%, P = 0.751). Suboptimal PIF was associated with shorter time to first COPD exacerbation (3.8±2.7 vs 4.9±3.0 months, P = 0.048). The mortality rate at 12 months was higher in the suboptimal cohort but not significantly different (6.5 vs 2.8%, P = 0.073). Conclusion Over one-third of outpatients with stable moderate to very severe COPD had a suboptimal PIF against a medium low resistance DPI. The phenotype of suboptimal PIF was short stature, female, and Black. Suboptimal PIF status was associated with shorter time to moderate/severe COPD exacerbations compared with optimal PIF.

Clinical Burden of Chronic Obstructive Pulmonary Disease in Patients with Suboptimal Peak Inspiratory Flow

“…SGRQ and CAT provide a comprehensive assessment of the COPD-specifc health status of patients [1]; therefore, a signifcant diference between CAT scores in participants with sPIF and those with oPIF suggests that suboptimal PIF may be generally associated with poor health status. A signifcant association between sPIF and high levels of dyspnea and poor COPD-related health status was also recently demonstrated in outpatients with stable moderateto-very severe COPD and sPIF [36].…”

Utility of peak inspiratory flow measurement for dry powder inhaler use in chronic obstructive pulmonary disease

“…A prospective, observational study by Mahler et al [7 ▪▪ ] of patients from seven US outpatient centers, measured PIF using the In-Check DIAL G16 inspiratory flow meter set to medium low resistance. Patients were classified by suboptimal (<60 l/min) or optimal PIF (≥60 l/min).…”

Personalizing Selection of Inhaled Delivery Systems in Chronic Obstructive Pulmonary Disease

“…For clinical applications, an optimal PIFr ⩾60 L/min has been proposed for DPIs with low to medium-high resistance and ⩾30 L/min for high-resistance DPIs ( 40 , 42 , 43 ). Patients with suboptimal PIFr may be unable to completely inhale the powder medication out of the DPI, thereby leading to reduced delivery of the fine-particle dose to the lower respiratory tract, adversely affecting outcomes ( 44 – 46 ).…”

“…Moreover, patients with suboptimal PIFr have greater symptom burden (as measured using the mMRC scale [ P = 0.003] and the COPD Assessment Test [ P < 0.01]) and a shorter time to first exacerbation compared with patients with optimal PIFr ( P = 0.048) ( 46 ). In addition, in a cross-sectional, multicountry study of 1,434 patients with COPD using DPIs for maintenance therapy, Leving and colleagues ( 30 ) showed that patients with suboptimal PIFr had higher medication costs compared with those with optimal PIFr (cost ratio, 1.07 [95% CI, 1.01–1.14]).…”