Development and Validation of aSensor-Integrated Metered Dose Inhalerfor Adherence Assessment

Abstract

Background: Poor adherence to inhaler therapy is a major challenge in the management of asthma and Chronic
obstructive pulmonary disease (COPD). Smart inhalers can objectively track medication use, but the majority of
available devices are costly and less feasible in resource-limited settings. Aim: The aim of the study was to develop
a low-cost sensor-integrated metered dose inhaler (MDI) and evaluate its usefulness in monitoring adherence and
improving disease control in asthma and COPD patients. Methods: The study was conducted in two stages.
First, an MDI with an MQ2 gas sensor was built, including an ESP32 microcontroller, rechargeable battery,
and Bluetooth/Wi-Fi-based data transfer. Second, we performed a prospective single-arm interventional study in
60 adults with asthma or COPD on MDI therapy. Participants were followed for 12 weeks, and adherence was
objectively measured using sensor-recorded data. Disease control was evaluated with American College Testing
(ACT) for asthma and Common admission test (CAT) for COPD at baseline, 4, 8, and 12 weeks. Exacerbations,
satisfaction, and ease of use were also recorded. Results: Good adherence increased from 16.7% at baseline to
60.0% at 12 weeks, and poor adherence decreased from 30.0% to 6.7%. Mean ACT/CAT scores increased from
16.8 ± 4.1 to 23.0 ± 3.1 over 12 weeks (P < 0.001). Adherence was moderately positively correlated with disease
control (r = 0.62; P < 0.001). Of the patients who were followed up, 66.7% had no exacerbations. The device
was well received, with 80.0% of patients reporting satisfaction and 81.7% finding it easy or very easy to use.
Conclusion: The MDI with integrated sensor improved asthma and COPD patients’ medication adherence and
disease control over 12 weeks. Its low cost, objective monitoring, and good usability support its potential use in
routine clinical practice, especially in resource-limited settings.