Measuring adherence to antiretroviral therapy in a diverse population using a visual analogue scale.
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.
Giordano
Thomas P
TP
Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
Guzman
David
D
Clark
Richard
R
Charlebois
Edwin D
ED
Bangsberg
David R
DR
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
D019380:Anti-HIV Agents