title: The efficacy of a computerized assessment of medication adherence in active substance users.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Psychiatry, University of California, San Francisco, CA, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Newville
authors.forename: James L
authors.initials: JL
authors.lastname: Sorensen
mesh_terms: D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D012372:ROC Curve; D012495:San Francisco; D057566:Self Report; D019966:Substance-Related Disorders / Q000453:epidemiology*; D013813:Therapy, Computer-Assisted / Q000379:methods*; D019562:Viral Load
keywords: adherence; antiretroviral therapy; computerized assessment; substance use