Purpose: To compare the performance of self-report instruments assessing adherence to antiretroviral therapy (ART) in patients starting ART for the first time and in a predominately Hispanic population.
Methods: Of 184 patients in a prospective observational cohort study of newly diagnosed, minority patients of low socioeconomic status, 54 were given Medication Event Monitoring System (MEMS) caps for their boosted protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI). They completed a 4-week recall visual analogue scale (VAS), the Adult AIDS Clinical Trial Group (AACTG) 4-day recall instrument, and a 1-month recall qualitative single-item measure every 3 months for up to 18 months in English or Spanish. Electronic pharmacy records recorded refill dates. Spearman correlation coefficients were calculated to compare self-report measures with MEMS data and pharmacy data.
Results: Of 46 patients with MEMS data, mean adherence was 84.7% (SD 35.6) by MEMS, 84.5% (SD 15.1) by pharmacy, 95.4% (SD 11.9) by VAS, 95.8% (SD 17.2) by AACTG, and 87.6% (SD 28.2) by qualitative single item. The correlation coefficient (CC) of VAS with MEMS was 0.37 (P < .01), and with pharmacy it was 0.34 (P < .01). The CC of the AACTG with MEMS was 0.32 (P < .01), and with pharmacy it was 0.28 (P < .01). The qualitative single item had a CC with MEMS of 0.24 (P < .01) and with pharmacy of 0.32 (P < .01). Spanish-speaking patients' VAS adherence had a CC of 0.40 (P < .01) with MEMS.
Conclusions: The VAS, AACTG, and qualitative single-item measures correlated significantly with MEMS and pharmacy data. Our data support self-administration of the VAS, even in Span-ish speakers.