Prediction of adherence to antiretroviral therapy: a one-year longitudinal study.

The aim of this longitudinal study was to identify the determinants of adherence to antiretroviral therapy (ART) in HIV patients over a period of 12 months. A total of 376 individuals living with HIV treated with ART participated in the study. Data were collected at baseline and at three, six, nine and 12 months. Variables assessed were adherence, attitude, outcome expectancies, self-efficacy, patient satisfaction with the relationship with their physician, provision of social support, optimism, CD4 cell count, viral load and side effects. Predictors of adherence in the Generalized Estimated Equation (GEE) were: high perception of self-efficacy (OR=1.68; 95%CI 1.27-2.22), positive attitude towards taking medication (OR=1.56; 95%CI 1.18-2.06), not living alone (OR=1.47; 95%CI 1.04-2.08) and being a male (OR=2.81; 95%CI 1.47-5.34). Subsequent analysis showed that a positive attitude towards taking medication was associated with a high level of patient satisfaction with their physician, high perceived social support, being optimistic, living with HIV for five years or less and experiencing no side effects. Also, a strong sense of self-efficacy was associated with positive perception of social support, high level of patient satisfaction with their physician and not living alone. These results suggest that interventions aimed at improving adherence to ART should focus on reinforcing self-efficacy and developing a positive attitude towards taking medication.