AEGiS-15IAC: Measuring adherence to antiretroviral therapy in a diverse population using a visual analogue scale (VAS).

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Measuring adherence to antiretroviral therapy in a diverse population using a visual analogue scale (VAS).

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. WeOrB1322)

Giordano TP, Guzman D, Clark R, Charlebois ED, Bangsberg DR
Baylor College of Medicine and the Houston VA Medical Center, Houston, TX, United States

BACKGROUND: Current methods of quantitatively assessing adherence to combination antiretroviral therapy (ART) are too cumbersome for clinical use. We examined the performance of a simple adherence tool based on a visual analogue scale (VAS), compared to one based on 3-day recall (3DR), using unannounced pill counts (UPC) in the place of residence as the gold standard, in a diverse population of subjects.

METHODS: We analyzed data from a prospective observational study of marginally housed indigent HIV-infected subjects receiving stable ART in San Francisco, CA. To be included in the analysis, subjects had to have 3 adherence assessments over no more than a 4-month period using all 3 methods of assessment. Pearson correlation coefficients were calculated, using UPC as the gold standard.

RESULTS: Complete data were available for 84 subjects. They were mostly male (83%), non-white (58%), and had a history of injection drug use (IDU; 64%). Mean adherence using the VAS, 3DR, and UPC was 82.5, 84.2, and 75.9%, respectively. The correlation between VAS and UPC was high (r=0.76), as was the correlation between 3DR and UPC (r=0.71; P=0.52 for the difference between the correlations). Both methods also correlated inversely with log HIV VL (r = -0.49 and -0.34, respectively; P=0.22 for the difference between the correlations). The VAS correlation with UPC was stable over time (r=0.57 and 0.73 at time 1 and time 3), and remained in African Americans (r=0.77), in subjects with less than 75% adherence (r=0.54), no more than a high school education (r=0.72), active IDU (r = 0.66), active alcohol use (r=0.90), active crack cocaine use (r=0.87), and in subjects on PI (r=0.80) or NNRTI (r=0.63).

CONCLUSIONS: A simple VAS tool to assess adherence performed as well as a more complicated 3DR tool in this diverse population. Adopting the VAS instrument may save the time of both researchers and subjects and will simplify data analysis. It is also brief enough that it could be self-administered and become an integral part of routine clinical practice, even in resource-poor settings.

Keywords: AEGIS, Anti-HIV Agents, Antiretroviral Therapy, Highly Active, HIV Infections, Pain Measurement, HIV Protease Inhibitors, Weights and Measures, HIV-1, Self Administration, Population, HIV, Prospective Studies, Acquired Immunodeficiency Syndrome, Substance-Related Disorders, HIV Seropositivity, Drug Therapy, Combination, San Francisco, Male, therapy, utilization, drug therapy

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WeOrB1322