Adherence logger for a dry powder inhaler: A new device for medical adherence research

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.