Inhaler adherence by new electronic technology (INCA) satisfactory in only 20% of patients

Published Online: September 1, 2016

Electronic monitors have become the gold standard for measuring adherence and several devices have been developed to assess inhaler use. These monitors give insight into the implementation phase of adherence; however, at present none assess technique of inhaler use in conjunction with time of use. To address this limitation, the Inhaler Compliance Assessment (INCA) device, an electronic adherence monitoring tool, was developed. This certified device records audio associated with an inhaler being used.  Analysis of this acoustic data allows for identification of the critical steps in correct inhaler use, including if the inhaler is opened, if the lever is moved (drug priming) and if there is an adequate inhalation.

In this study, “Irregular and ineffective: A quantitative observational study of the time and technique of inhaler use”, published in The Journal of Allergy and Clinical Immunology: In Practice, Sulaiman and colleagues used the INCA device to measure inhaler adherence in a cohort of respiratory patients recruited from general practices and community pharmacies within the Republic of Ireland. For this study, patients had a known respiratory diagnosis and were already prescribed salmeterol/fluticasone Diskus inhaler twice-daily. Once consented, patients were given a new 60-dose adapted Diskus inhaler with the INCA device attached. Patients were asked to use their inhaler as they normally would for one month.  After one month the INCA device was collected and analysis of the acoustic files was performed by two trained reviewers. Audio analysis allowed for accurate identification of inhaler technique over time. The primary endpoint of this study was to identify rates of inhaler adherence, with regards to time of use and technique of use, in a cohort of respiratory patients.

Over the one month study period the authors examined inhaler adherence in 103 patients with a diagnosis of either asthma or Chronic Obstructive Pulmonary Disease (COPD). Overall, there were 1135 missed doses, leading to an average “Attempted” adherence of 70%. The most common inhaler errors, identified by acoustic analysis of files recorded to the INCA device, were poor inspiratory effort (27%), multiple inhalations (25%), drug priming without an inhalation (19%) and exhalation into the device after drug priming but before inhalation (18%). The authors combined missed doses, technique errors and extended interval between doses (all errors in inhaler use) to calculate adherence as ‘Actual’ Adherence.  This was thought to reflect actual drug delivery when all these components of inhaler adherence are considered. In this patient cohort, combining these components of adherence led to an average ‘Actual’ Adherence of 47%, significantly lower than that recorded by the dose counter, 88%. Only 20 % of patients exhibited a “good” Actual adherence rate of at least 80%. Interestingly, the authors also identified four groups of inhaler users. One group of patients started with good adherence and ended with poor adherence, possibly related to being recruited into a clinical study. Another group had poor adherence throughout while another set of patients had good adherence throughout. Finally, one group of patients started with poor adherence and ended with good adherence, without any intervention. This highlights the large variation in inhaler adherence when measured longitudinally.

In this paper, with a novel electronic adherence monitor, the authors were able to combine missed doses, interval between doses and technique of inhaler use into a composite adherence score. The results extend prior findings regarding the high prevalence of poor inhaler adherence in patients with respiratory disease to include quality of use and identify specific targets for intervention.   

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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