Factors affecting adherence to antiretroviral therapy.

In both clinical trials and clinical practice, nonadherence to medications is widespread among patients with chronic diseases. The shift to combination therapies for treating human immunodeficiency virus (HIV)-infected individuals has increased adherence challenges for both patients and health-care providers. Estimates of average rates of nonadherence to antiretroviral therapy range from 50% to 70%. Adherence rates of <80% are associated with detectable viremia in a majority of patients. The principal factors associated with nonadherence appear to be patient-related, including substance and alcohol abuse. However, other factors may also contribute, such as inconvenient dosing frequency, dietary restrictions, pill burden, and side effects; patient-health-care provider relationships; and the system of care. We discuss the major reasons reported by HIV-infected individuals for not taking their medications. Improving adherence probably requires clarifying the treatment regimen and tailoring it to patient lifestyles.