OBJECTIVES : To be perfectly adherent to medication, patients need to follow the prescribers’ instructions and take the correct doses of medication at the correct time. This study examined the sociodemographic, behavioral, and clinical characteristics associated with 100% ART adherence among people living with HIV (PLWH) receiving medical care in Houston/Harris County, Texas.

METHODS : Data used for this study (n=1,073; weighted n=10,274) were obtained from the Houston Medical Monitoring Project survey conducted among PLWH in Houston/Harris County, Texas between 2009 and 2014. The combined ART adherence was defined as 100% adherence to medication dose, schedule, and instruction. The number of years since initial HIV diagnosis was classified as <5, 5-10 and >10 years. The Rao-Scott chi-square test and multivariable logistic models were used to determine the predictors of 100% ART adherence to medication dose, schedule, and instruction.

RESULTS : Overall, 54.4% of the PLWH were adherent to 100% medication dose, schedule, and instruction, with significant (p=0.022) variation noted across years since HIV diagnosis. PLWH who were diagnosed with HIV less than 5 years and between 5 and 10 years were approximately two times (aOR = 1.71, 95% CI = 1.13–2.57; aOR = 1.69, 95% CI = 1.10–2.59; respectively) more likely to be adherent to all medication requirements compared to those diagnosed for more than 10 years. Among PLWH who were diagnosed with HIV for less than 5 years, significant predictors of all adherence were incarceration (aOR = 4.51, 95% CI = 1.27–16.05), confidence taking all or most medication as directed (aOR = 5.28, 95% CI = 1.29–21.67), and prior HPV vaccination (aOR = 3.23, 95% CI = 1.03–10.08).

CONCLUSIONS : Predictors of ART adherence varied significantly by years since HIV diagnosis. Intervention programs to enhance optimal ART adherence should consider the predictors identified in this study.