Feasibility of an ingestible sensor-based system for monitoring adherence to tuberculosis therapy

Abstract

Poor adherence to tuberculosis (TB) treatment hinders the individual's recovery and threatens public health. Currently, directly observed therapy (DOT) is the standard of care; however, high sustaining costs limit its availability, creating a need for more practical adherence confirmation methods. Techniques such as video monitoring and devices to time-register the opening of pill bottles are unable to confirm actual medication ingestions. A novel approach developed by Proteus Digital Health, Inc. consists of an ingestible sensor and an on-body wearable sensor; together, they electronically confirm unique ingestions and record the date/time of the ingestion. A feasibility study using an early prototype was conducted in active TB patients to determine the system's accuracy and safety in confirming co-ingestion of TB medications with sensors. Thirty patients completed 10 DOT visits and 1,080 co-ingestion events; the system showed 95.0% (95% CI 93.5-96.2%) positive detection accuracy, defined as the number of detected sensors divided by the number of transmission capable sensors administered. The specificity was 99.7% [95% CI 99.2-99.9%] based on three false signals recorded by receivers. The system's identification accuracy, defined as the number of correctly identified ingestible sensors divided by the number of sensors detected, was 100%. Of 11 adverse events, four were deemed related or possibly related to the device; three mild skin rashes and one complaint of nausea. The system's positive detection accuracy was not affected by the subjects' Body Mass Index (p = 0.7309). Study results suggest the system is capable of correctly identifying ingestible sensors with high accuracy, poses a low risk to users, and may have high patient acceptance. The system has the potential to confirm medication specific treatment compliance on a dose-by-dose basis. When coupled with mobile technology, the system could allow wirelessly observed therapy (WOT) for monitoring TB treatment as a replacement for DOT.

Conflict of interest statement

Competing Interests: Proteus Digital Health which funded the study is also the employer of authors Kit Yee Au-Yeung PhD, Greg Moon M.D. and Lorenzo DiCarlo M.D. A novel RaisinTM is currently under development that electronically confirms medication ingestions using an ingestible event marker (Proteus Digital Health, Inc. Redwood City, CA). There are no further patents, products in development, or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Figures

Figure 1. Overview of the future, fully developed system to support Wirelessly Observed Therapy (WOT).