Evaluating Measures of Pre-ART Adherence Readiness Through Associations with ART Adherence in the Early Months of Treatment

Determining a patient's readiness to adhere well prior to the start of ART provides an opportunity to address adherence barriers before poor pill taking habits form, and ultimately improve clinical outcomes and resource utilization. Three methods of measuring adherence readiness and their comparative utility in predicting early ART adherence were examined in a sample of 176 patients preparing to start ART. Data were analyzed data from a randomized controlled trial of a cognitive-behavioral adherence intervention. Three measures of pre-ART adherence readiness (provider estimate, 1 week vitamin practice trials, and self-report [HIV Medication Readiness Scale; Transtheoretical Stages of Change item (TSOC)] were examined in association with measures of (1) ART initiation, (2) ART retention, (3) mean electronic dose-taking adherence, and (4) achievement of optimal (85+ % dose-taking) adherence, over the first 3 months of ART. Of the 176 patients, 166 (94.3%) started ART; 124 (74.7% of those who started ART; 70.5% of whole sample) completed the first 3 months of ART. Among the 124 still on ART at month 3, mean dose-taking adherence was 79.3%, and 62 (35.2% of whole sample) achieved optimal adherence. The provider estimate was the only readiness measure significantly associated with each of the four measures of early ART adherence, and it had the highest concordance statistics (71% PPV and 62.3% NPV) with optimal early ART adherence. Practice trial adherence was only associated with ART initiation and retention. Dose-taking adherence over 3 months was significantly correlated with the provider estimate and the two self-reports. Each method of early treatment adherence has its own utility, but the provider estimate had the best overall performance in predicting early ART adherence.