title: Measuring adherence to antiretroviral therapy in a diverse population using a visual analogue scale.
abstract: OBJECTIVE
  To examine the performance of an instrument to assess adherence based on a visual analogue scale, compared to an instrument based on 3-day recall, using unannounced pill counts in the place of residence as the gold standard.
  
  
  METHODS
  We prospectively assessed adherence to antiretroviral therapy in 84 marginally housed indigent HIV-infected patients who were receiving stable antiretroviral therapy in San Francisco, California, with three adherence assessments over no more than 4 months.
  
  
  RESULTS
  Mean adherence using the visual analogue scale, 3-day recall, and unannounced pill count methods were 82.5%, 84.2%, and 75.9%, respectively. The correlation between visual analogue scale and unannounced pill count was high (r = 0.76) and was not statistically different from that between 3-day recall and unannounced pill count (r = 0.71; p =.52). Both methods were also similarly inversely correlated with HIV viral load (r = -0.49 and -0.34, respectively; p =.22 for the difference in the correlations). The visual analogue scale correlation with unannounced pill count was stable over time and remained high in all subpopulations examined.
  
  
  CONCLUSIONS
  A visual analogue scale to assess adherence was performed as well as a more complicated 3-day recall instrument in this diverse population. Given its simplicity, the visual analogue scale adherence instrument will be useful in research and may be useful in routine patient care.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Giordano
authors.forename: David
authors.initials: D
authors.lastname: Guzman
authors.forename: Richard
authors.initials: R
authors.lastname: Clark
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Charlebois
authors.forename: David R
authors.initials: DR
authors.lastname: Bangsberg
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000473:pathology; D006703:Ill-Housed Persons; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012495:San Francisco; D012646:Self Administration / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D017664:Uncompensated Care
chemical_list: D019380:Anti-HIV Agents