Irregular and Ineffective: A Quantitative Observational Study of the Time and Technique of Inhaler Use.

BACKGROUND Cross-sectional observational studies suggest that between 50% and 60% of patients misuse a dry powder inhaler, whereas studies with electronic monitors indicate that patients sometimes overuse/underuse their inhalers. It is not known what impact errors and erratic use have on inhaler adherence. OBJECTIVES The purpose of this study was to longitudinally quantify when and how patients adhered to a twice-daily preventer treatment by using a novel acoustic recording device attached to an inhaler (INhaler Compliance Assessment). METHODS Patients with a history of asthma or chronic obstructive pulmonary disease (n = 123) from primary care and community pharmacies were given an INhaler Compliance Assessment-adapted inhaler for 1 month. Analysis of the audio files provided quantitative information on time and technique of inhaler use. RESULTS Data were available for 103 patients. Twenty-one patients (20%) used their inhaler in the correct manner at the correct interval. There were 5045 audio files with attempted inhalations, of which 1204 had technique errors (24%). Errors included inadequate flow (27%), drug priming without inhalation (19%), exhalation into the inhaler (18%), and multiple inhalations (25%). On average, participants made errors 20% of the time. Of 60 doses expected to be taken in a month per person, on average 49 doses (82%) were attempted and when errors were accounted for, the average number of actual doses taken was 34 doses (57%; P < .01) comparing attempted to actual doses. DISCUSSION These data highlight that ineffective and irregular inhaler use is common and when combined in a single calculation indicate that only 20% of participants used their inhaler correctly and on time.