Pharmacoadherence: A new term for a significant problem

In 2003, the World Health Organization declared nonadherence to medical treatment a major public health concern, particularly among patients with chronic conditions.1 Research has found that adherence to long-term treatment regimens associated with chronic conditions is problematic,2,–6 with nonadherence rates in the longer-term regimens ranging from 20% to 82%.7,–11 Patient adherence to medical treatment regimens has been shown to be directly associated with health outcomes,12 with poor adherence or nonadherence contributing to increased morbidities and mortalities.13 Unfavorable outcomes associated with nonadherence also result in annual health care costs of approximately $100 billion.14 What exactly, though, are we referring to when we discuss the concept of adherence? Adherence refers to the extent to which an individual’s behavior regarding a medical treatment regimen corresponds with the agreed-on recommendations of a health care professional.15 Distinct in meaning from the term “compliance” in the health care lexicon, “adherence” indicates collaboration between the patient and the health care professional,16,–18 whereas “compliance” suggests obedience to the health care professional.16,19,–23