Patch nonwear accounts for more than half of apparent nonadherence in a digital medicine system
- 1Beth Israel Deaconess Medical Center
Abstract
Digital-medicine systems can objectively confirm medication ingestion, but interpretation of a no-detection day depends on whether the wearable receiver was in contact with the body. We analyzed 997 person-days from 20 outpatients prescribed aripiprazole through Abilify MyCite by integrating ingestion records with patch-contact data; 17 participants also contributed smartphone sensing. Of 322 days without a detected ingestion, 53.7% had insufficient patch wear. Counting all no-detection days as nonadherent yielded an apparent nonadherence rate of 32.3%, whereas conditioning on adequate wear yielded 18.1%. Because adherence during patch-off periods is unobserved, the rate is bounded between 14.9% and 32.3%. These findings support a three-state outcome that distinguishes detected ingestion, no ingestion despite adequate wear, and patch-off or indeterminate days. Among 744 patch-worn days, detected ingestion was more likely on days that more closely matched each participants usual activity pattern (odds ratio 1.52, 95% credible interval 1.14-2.03) and when participants spent more time at home around the habitual dose period (1.31, 1.04-1.64). These behavioral associations were exploratory and characterize the context of medication-taking rather than causal effects. Overall, device wear was integral to interpretation of the adherence outcome, and passive behavioral measures were most interpretable after observation status was established.
AUTHOR SUMMARYDigital tools can help researchers measure whether medications are taken in everyday life, but these tools are only useful when we know whether they were actually able to observe the behavior of interest. We studied 20 adults using a digital aripiprazole system in which an ingestible sensor communicates with a wearable patch. We found that more than half of days with no detected ingestion occurred when the patch was not worn long enough for a dose to have been observed. As a result, simply treating every day without a detected signal as medication nonadherence substantially overestimated apparent nonadherence.
We therefore propose distinguishing three types of days: days when an ingestion is detected, days when no ingestion is detected despite adequate patch wear, and days when medication-taking cannot be determined because the patch was not adequately worn. We also explored whether smartphone-derived measures of daily behavior were related to medication-taking. More typical daily activity patterns and being at home around the usual dosing time were associated with detected ingestion, but these findings were exploratory and did not support reliable day-ahead prediction. Our findings highlight the importance of establishing whether digital health data are observable and interpretable before drawing clinical conclusions.
Related
- Digital health and artificial intelligence in paediatric respiratory medicine: what clinicians need to know and what is coming next
- Nativity and US Residence Duration and Colorectal Cancer Screening Nonadherence.
- Common barriers and facilitators to the implementation of digital medicine in chronic respiratory diseases: a systematic review of reviews
- Usability of digital medicine systems in patients with schizophrenia or schizoaffective disorder
- Blood Pressure Reduction in Multiomic Digital Food-as-Medicine: a single-arm cohort study with a regression-to-the-mean-adjusted estimand
BibTeX
@misc{byun2026patch,
title = {{Patch nonwear accounts for more than half of apparent nonadherence in a digital medicine system}},
author = {A. J. S. Byun and D. Chen and H. Notsu and S. Li and V. Lisowski and E. Lane and S. Ryan and J. Torous},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.21.26363541},
url = {https://www.medrxiv.org/content/10.64898/2026.09.21.26363541v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Patch nonwear accounts for more than half of apparent nonadherence in a digital medicine system
AU - A. J. S. Byun
AU - D. Chen
AU - H. Notsu
AU - S. Li
AU - V. Lisowski
AU - E. Lane
AU - S. Ryan
AU - J. Torous
PY - 2026
DA - 2026/09/21
PB - medRxiv
DO - 10.64898/2026.09.21.26363541
UR - https://www.medrxiv.org/content/10.64898/2026.09.21.26363541v1
AB - Digital-medicine systems can objectively confirm medication ingestion, but interpretation of a no-detection day depends on whether the wearable receiver was in contact with the body. We analyzed 997 person-days from 20 outpatients prescribed aripiprazole through Abilify MyCite by integrating ingestion records with patch-contact data; 17 participants also contributed smartphone sensing. Of 322 days without a detected ingestion, 53.7% had insufficient patch wear. Counting all no-detection days as nonadherent yielded an apparent nonadherence rate of 32.3%, whereas conditioning on adequate wear yielded 18.1%. Because adherence during patch-off periods is unobserved, the rate is bounded between 14.9% and 32.3%. These findings support a three-state outcome that distinguishes detected ingestion, no ingestion despite adequate wear, and patch-off or indeterminate days. Among 744 patch-worn days, detected ingestion was more likely on days that more closely matched each participants usual activity pattern (odds ratio 1.52, 95% credible interval 1.14-2.03) and when participants spent more time at home around the habitual dose period (1.31, 1.04-1.64). These behavioral associations were exploratory and characterize the context of medication-taking rather than causal effects. Overall, device wear was integral to interpretation of the adherence outcome, and passive behavioral measures were most interpretable after observation status was established. AUTHOR SUMMARYDigital tools can help researchers measure whether medications are taken in everyday life, but these tools are only useful when we know whether they were actually able to observe the behavior of interest. We studied 20 adults using a digital aripiprazole system in which an ingestible sensor communicates with a wearable patch. We found that more than half of days with no detected ingestion occurred when the patch was not worn long enough for a dose to have been observed. As a result, simply treating every day without a detected signal as medication nonadherence substantially overestimated apparent nonadherence. We therefore propose distinguishing three types of days: days when an ingestion is detected, days when no ingestion is detected despite adequate patch wear, and days when medication-taking cannot be determined because the patch was not adequately worn. We also explored whether smartphone-derived measures of daily behavior were related to medication-taking. More typical daily activity patterns and being at home around the usual dosing time were associated with detected ingestion, but these findings were exploratory and did not support reliable day-ahead prediction. Our findings highlight the importance of establishing whether digital health data are observable and interpretable before drawing clinical conclusions.
ER -