The WHO defines adherence as the extent to which a person’s behavior – taking medication, following a diet, and/or executing lifestyle changes – corresponds with agreed recommendations from a health care provider.1 Beyond that definition, adherence can be understood in three categories:2
- Initiation – occurs when the patient takes the first dose of a prescribed medication
- Execution – is the extent to which a patient’s actual dosing corresponds to the prescribed dosing regimen, from initiation until the last dose
- Discontinuation – occurs when the patient stops taking the prescribed medication for whatever reason(s)
Researchers have used the terms compliance and persistence amongst others in the past, but the term adherence is now widely accepted.3
- "What Is Adherence?". Adherence to Long-Term Therapies - Evidence for Action. WHO, 2003. Web. 1 Aug. 2012.
- Ascertaining Barriers for Compliance: Policies for Safe, Effective and Cost-effective Use of Medicines in Europe. Vol. 7.1: ABC Project, 2012. Print.
- Vrijens, B. A New Taxonomy for Describing and Defining Adherence to Medications. Br J Clin Pharmacol 73.5 (2012): 691-705.