Antiretroviral therapy: factors associated with adherence.

Clinical effectiveness of the new highly active antiretroviral therapies depends in large part on patients' ability to adhere to demanding medication regimens because the suboptimal drug levels associated with nonadherence are, in turn, associated with the development of antiretroviral resistance. However, definitions of adherence are inconsistent, and the concept is difficult to measure. Adherence to medical and health regimens is the outcome of a dynamic process of human behavior and interaction. Factors influencing this process include characteristics of the regimen, the provider, the patient, and society.