Adherence and concordance

Adherence and concordance

Patients make important contributions to rational prescribing decisions. Their beliefs and expectations affect the goals of therapy and help in judging the acceptable benefit/harm balance when selecting treatments. They will often play a key role in monitoring treatment, not least by providing early warning of adverse events. Patients who have been involved in clear communication with prescribers concerning reasons for drug selection, goals, duration of treatment, and potential adverse effects have improved adherence to treatments, more confidence in prescribers, and greater satisfaction with health-care services. Thus, patients should, whenever possible, be fully informed about their medicines.


Medication compliance is the act of taking medication on schedule or taking medication as prescribed, to achieve the desired health benefit i.e. following a healthcare professional's advice. Adherence includes an indication of the tenacity that patients need to achieve in sticking to a therapeutic regimen, and also takes into consideration social and environmental influences. For example, with aging populations, older adults often find themselves with multiple chronic conditions requiring management of multiple medications. This polypharmacy phenomenon is often associated with poor adherence. Or, patients may not fully adhere on grounds of gender, ethnicity, education or beliefs.

Noncompliance/non-adherence have unwanted outcomes for both the patient (unnecessary disease progression and complications, reduced functional abilities and quality of life, more physician visits than required and unneeded medication changes) and the health provider (increased use of expensive, specialized medical resources).


The factors underlying noncompliance are myriad:

  • Complexity of the regimen, which can lead to mistakes in doses, taking either too much or forgetting to take any
  • Failure of the patient to understand the importance of adherence, with treatments perceived as ineffective or unsafe
  • The patient's perception of barriers to adherence e.g. an unwillingness to make lifestyle changes to accommodate a recommended treatment regimen


The AIDES method to improving medication adherence has been devised around evidence-based practices, and consists of a set of strategies which can be used by health professionals to improve care provision. AIDES stands for:

  • Assessment- completion of a comprehensive evaluation of medication(s) being prescribed
  • Individualization of the regimen in collaboration with the patient
  • Documentation- providing printed information suitable for the patient, to improve doctor-patient communication
  • Education- providing accurate and ongoing information tailored to the needs of the patient
  • Supervision- continuing after initiation of the drug regimen



The idea of concordance was introduced, as a less-paternalistic concept to enhance the relationship between the prescriber and their pateint. It implies an agreement about the therapeutic regimen that the patient will follow, made between the prescriber and patient.