Health care education, delivery, and quality
Adherence logger for a dry powder inhaler: A new device for medical adherence research

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Background

Adherence to inhaled steroid regimens is frequently poor. Finding ways to improve adherence depends on the ability to measure time and date of inhaler use reliably and to detect deliberate dose dumping. There is no such monitor for the popular new dry powder inhalers.

Objective

To develop and test an electronic monitor for a dry powder inhaler that will provide information on the time and date of use.

Methods

An electronic adherence monitor for the Advair Diskus dry powder inhaler was developed and tested. In this device, inhaler use is determined by detecting and recording the motion of the drug delivery lever in the inhaler with a magnetic sensor. An additional electronic interface and software were also developed to allow the adherence data to be uploaded to a computer for display and analysis.

Results

System and reliability tests involving multiple-day and repeated-use tests of the adherence monitor demonstrate the overall performance and reliability of the device, and specifically its ability to record the time and date of dose delivery. In the repeated-use test, 300 successive actuations of the dose delivery lever were correctly sensed and recorded without error.

Conclusion

The simple-to-use, low-cost, reusable adherence monitor accurately records time and date of inhaler use and thus allows clinical monitoring and adherence studies in patients using the Advair Diskus dry powder inhaler. The same technology should be adaptable to other dry powder inhalers, including the Pulmicort Tubuhaler and the Symbicort Tubuhaler.

Section snippets

Methods

Described here is an electronic monitor to record the use of the Advair Diskus DPI (GlaxoSmithKline, Brentford, Middlesex, United Kingdom), currently the most widely used DPI. Advair, a combination ICS (fluticasone propionate) and long-acting bronchodilator (salmeterol xinafoate), is delivered through a disk-shaped inhaler, the Diskus, containing 60 doses. Drug delivery requires 3 operations: “open” (the case), “click” (the lever that advances a dose of dry powder into the mouthpiece), and

Results

Two initial verification tests were performed to demonstrate the operation of the DAL system. The first verification was designed to demonstrate the overall operation of the entire system, including the data collection module, the interface module, and the software. The second verification was designed to demonstrate the reliability of the lever sensing system.

Design constraints

The DAL described here satisfies several important design constraints, including the need for (1) extremely small size; (2) noninterfering operation, so that the patient operates the Diskus in a normal fashion; (3) external attachment, so that the DAL can be attached without disassembling the Diskus and possibly interfering with drug delivery; (4) extended battery life; (5) simplicity, to promote reliability; and (6) low cost, to make large-scale clinical studies using the DAL feasible.

Performance

In the

Conclusion

We have developed a device to record the use of the Advair Diskus DPI, a technology that should be adaptable to other DPIs. This device should enable researchers and clinicians to monitor adherence to this new formulation of an important asthma medication in the same way that adherence monitors have been used previously with metered-dose inhalers.

References (12)

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Supported by the University Research Foundation and the National Heart, Lung and Blood Institute (HL04337-01; Dr Apter).

Disclosure of potential conflict of interest: The authors have no financial relationship with any company concerning the work described in this manuscript, nor any other conflict of interest.

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Copyright © 2004 American Academy of Allergy, Asthma and Immunology. Published by Mosby, Inc. All rights reserved.