START (Supporting Treatment Adherence Readiness through Training) Improves Both HIV Antiretroviral Adherence and Viral Reduction, and is Cost Effective: Results of a Multi-site Randomized Controlled Trial

The START (Supporting Treatment Adherence Readiness through Training) intervention was examined for its effects on ART adherence and virologic suppression relative to usual care. A sample of 176 clients about to start or restart ART were randomized (83 to START, 93 to usual care) at HIV clinics in the Los Angeles area. Primary outcomes included electronically monitored dose-taking adherence and HIV viral load; primary end points were months 6 and 24, with group differences examined using nonresponse-weighted means or proportions, effect sizes, and significance testing. Item nonresponse was addressed using multiple imputation. 166 (94.3%) participants started ART, of whom 124 (74.7%) were still in care at month 6, and 90 (54.2%) at month 24. In comparison to the usual care control group, the START group had higher dose-taking adherence at month 6 (86.2% vs. 71.6%, d = 0.56, p = 0.01), which was sustained through month 24 (86.0% vs. 61.1%, d =1.01, p < 0.0001). While rates of undetectable viral load did not differ between groups at month 6 or 24, the mean reduction in viral load (log₁₀ copies/mm³) at month 24 was significantly greater in the intervention arm (3.0 vs. 2.7; d = 0.40, p = 0.047). An estimated cost of $132 per person was needed to obtain a 10% increase in dose-taking adherence over 24 months from the intervention. These findings suggest that START is cost effective in producing a medium to large effect on dose-taking adherence that is durable over 24 months, and a modest long-term effect on viral reduction.