Consider PIF and inhaler technique when choosing COPD treatment

A study assessing the effectiveness of dry powder inhalers in maintenance treatment of COPD has found almost one in three participants did not generate the optimal peak inspiratory flow required for their breath-actuated device to work effectively.

The PIFotal study found a patient’s inability to achieve peak inspiratory flow (PIF) was also associated with worse health outcomes, sparking a call for healthcare professionals to assess and review the best treatment and inhaler type for each patient.

One of the study’s authors, Professor Sinthia Bosnic-Anticevich, of Sydney University, said the study confirmed inhaler use was challenging for a proportion of patients and had a significant impact on health outcomes.

“We’ve always known that the breathing manoeuvre is very important, be it dry powder inhalers (DPI), or metered dose inhalers (pMDI) or soft mist inhalers (SMI),” she said.

“The patient has to be able to inhale correctly or sufficiently, that is, while coordinating actuating their device is important for the pMDI and SMI. We’ve noticed over many years that this breathing manoeuvre can be challenging for DPIs if the patient cannot generate enough effort to inhale sufficiently.

“With this study we were able to focus on DPIs specifically and have not just the visual assessment, which is somewhat subjective, but an objective measure of inhalation effort, that is peak inspiratory flow.”

Published in Nature Primary Care Respiratory Medicine the multicentre study of 1434 COPD patients in Australia and several EU countries aimed to replicate real-world settings in its assessment of the medication use. It found patients made multiple errors in technique when using their dry-powder inhalers, from not achieving optimal inhalation to not exhaling completely before use, or not sealing the mouthpiece with their lips and teeth. Different DPIs required different PIF.

Almost one in three patients in the study (29%) did not generate the optimal PIF for their own DPI device, it found.

More than one in ten patients (13%) were unable to produce a sufficient PIF, indicating healthcare professionals should consider selecting different inhalers with lower internal resistance or inhalers with zero internal resistance such as pMDIs or SMIs, the authors said.

A suboptimal PIF (sPIF) was associated with worse health status, the study found, but no significant relation was seen with moderate and severe exacerbations compared with participants with optimal PIF.

Furthermore, 16% of patients were able to generate an optimal PIF but failed to do so, suggesting “that there is potential for interventions targeting PIF such as by improving inhalation technique.”

Professor Bosnic-Anticevich, Head of the Quality Use of Respiratory Medicines Group at the Woolcock Institute of Medical Research, said while they had been promoting correct inhaler technique “for decades”, it was sometimes lost in the overall condition management.

“The reality is that [inhaler technique] does get lost, but the study does show, once again, that if a patient isn’t actually able to use their inhalers then they will have poorer outcomes. What this study shows it that device selection, independent of drug class, is critical” she said.

“Greater knowledge by the healthcare professionals of the different inhalers, and their patients’ own ability to use a particular inhaler, is important. Following up and checking that a patient is managing okay on an inhaler is also critically important. It all starts off with there being an awareness from the prescriber.”

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