Comparison of digital vs. mechanical peak flow meters in a real-world setting (ID 567)
University of Oxford
Funding: This was an unfunded third year medical student project, but minor costs were covered by internal University of Oxford funding.
HFA, PJT, and GNH receive funding from the NIHR HealthTech Research Centre in Community Healthcare at Oxford Health NHS Foundation Trust. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.
Abstract
Aim:Peak flow meters (PFMs) record peak expiratory flow rate (PEF) and can be used at home as part of asthma diagnosis or monitoring. A digital PFM (Smart Peak Flow) is now available for purchase (£48.49, Amazon.co.uk, June 2024) which uses an app to record results and allows data sharing with health professionals. However its accuracy compared to traditional mechanical PFMs has not been tested outside of controlled laboratory settings. Clinicians need confidence in relative accuracy to be able to support patients wishing to purchase the device, as well as to inform potential NHS uptake.
We aimed to compare measurement accuracy and repeatability of digital and mechanical PFMs, and acceptability of the digital PFM, in real-life participants.
Methods:
The main study was a single timepoint assessment of adult participants, with and without asthma. Mechanical and digital PFMs were attached in series and participants performed nine successive measurements.
Additionally, some participants with asthma performed two weeks of home monitoring, followed by a mixed methods survey about their experiences.
Results:
Paired PEF data was available for 91 participants, providing 819 paired PEF measurements. PEF measured 27.2 (95% CI 26.3 to 28.2) L/min higher on the digital PFM (p<0.001). Agreement and differences were consistent throughout the PEF range (see Bland-Altman plot, Figure). Repeatability was similar between mechanical and digital PFMs (within-person co-efficient of variation p=0.36).
The monitoring sub-study (n=9) found some technical challenges with the digital PFM including lighting and ‘time-out’ issues but users became more adept at successfully recording measurements with time.
Conclusion:
The measurement discrepancy found between devices is unlikely to be clinically significant, especially with repeated use of the same device as recommended in guidelines. Patients wishing to purchase this device could be supported by their clinician. Further studies assessing clinical and cost-effectiveness are needed before wider NHS implementation.
Conflicts of interest: Smart Respiratory Products Ltd provided Smart Peak Flow digital PFMs free of charge for the study, but had no role in the analysis or interpretation of data. They do not provide any funding or support to any of the co-authors.
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