Related Experiment Video
Updated: May 11, 2026

Digital Home-Monitoring of Patients after Kidney Transplantation: The MACCS Platform
Published on: April 12, 2021
The efficacy of a computerized assessment of medication adherence in active substance users
Howard Newville1, James L Sorensen
1Department of Psychiatry, University of California, San Francisco, CA, USA.
Background:
Self-reports of medication adherence are subject to recall errors and social desirability bias. The visual analogue scale (VAS) is a brief measure and minimally burdensome. Its accuracy among substance users needs confirmation.
Methods:
We administered the VAS on an audio computer-assisted self-interview (ACASI) to 102 HIV-positive active substance users. Viral load (VL) was obtained via chart review. Cohen κ assessed the overall agreement between VL suppression and adherence, and a receiver-operator characteristic (ROC) curve assessed the diagnostic performance.
Results:
The VAS estimates of adherence correlated with VL. Various cutoffs for adherence were associated with VL suppression, demonstrating fair to moderate agreement through κ. Area under the curve (AUC) demonstrated that the ACASI-administered VAS strongly predicted VL suppression (AUC = 0.79).
Discussion:
The VAS administered by ACASI is viable for measuring highly active antiretroviral therapy (HAART) adherence among substance users. Its benefits as a screening instrument may make it useful for both clinical and research purposes.
Related Concept Videos
Measurement of Bioavailability: Pharmacodynamic Methods
Drug Therapy
Antianxiety Medications
Therapeutic Drug Monitoring: Affecting Factors
Modified-Release Drug Delivery Systems: Bioavailability
Bioavailability Study Design: Healthy Subjects Versus Patients
Therapeutic Drug Monitoring: Drug Analysis Methods