Evaluation of multiple measures of antiretroviral adherence in the Eastern European country of Georgia

INTRODUCTION: There is little information on adherence to antiretroviral therapy (ART) in the Eastern European region. This prospective study evaluated multiple measures of adherence and their association with viral suppression among HIV patients in Georgia. METHODS: A prospective cohort study enrolled 100 consecutive antiretroviral-naïve adult (age ≥18 years) patients, who were followed for three months. Adherence was assessed by medication refill and three self-report measures (an AIDS Clinical Trial Group [ACTG] tool for four-day adherence, a visual analogue scale [VAS] and a rating task for 30-day adherence). The VAS represented a line anchored by 0 and 100% corresponding to the percentage of prescribed doses taken. The rating task asked patients to rate their ability to take all medications as prescribed, with responses categorized into six levels of adherence: very poor (0%), poor (20%), fair (40%), good (60%), very good (80%) and excellent (100%). Patients with adherence of ≥95% by medication refill, ACTG and VAS, and ≥80% by rating task, were defined as adherent. RESULTS: Of 100 patients enrolled, eight had missing data and were excluded from analysis. Among the remaining 92 patients, the median age was 39 years, and 70% were men. Major modes of HIV acquisition were injection drug use (IDU; 47.3%) and heterosexual contact (44.1%). The proportions of adherent patients were as follows: 68% by medication refill, 90% by ACTG questionnaire, 38% by VAS and 42% by rating task. On average, four months after commencing ART, 52 (56.5%) patients had a viral load <400 copies/ml and 26 (28.3%) patients had a viral load <50 copies/ml. Of 43 persons with a history of IDU, 22 (51.2%) reached a viral load of <400 copies/ml. In multivariate analysis, only refill adherence was a statistically significant predictor of viral suppression of <400 copies/ml: the risk ratio was 1.7 (95% CI: 1.1–2.8). Refill adherence, VAS and rating task were associated with viral suppression of <50 copies/ml. Non-IDUs were twice as likely to achieve viral load <50 copies/ml compared to IDUs. Refill adherence had the largest area under the receiver-operating characteristic curve for predicting viral suppression. CONCLUSIONS: Medication refill adherence was the strongest predictor of viral suppression. IDUs can achieve optimal virologic outcomes, but may require additional adherence support.