Correct use of medicine is a crucial factor in effective patient self-care and hence positive outcomes in any chronic disease. Different concepts have evolved from the notion of correct use of medicine, such as compliance, adherence and concordance.

Compliance is defined as “the extent to which the patient follows the health professionals’ advice and takes the treatment”. This concept is being replaced by the term ‘adherence’, as compliance may imply a submissive, uninvolved patient in a paternalistic setting.

Adherence is defined as “…the extent to which a person’s behaviour – taking medication, following a diet, and/or executing lifestyle changes – corresponds with agreed recommendations from a healthcare provider”.

Concordance is a new concept which has evolved and is defined as “agreement between the patient and healthcare professional, reached after negotiation that respects the beliefs and wishes of the patient in determining whether, when and how their medicine is taken, and (in which) the privacy of the patient’s decision (is recognised)”.

For the purposes of this article, the term ‘adherence’ will be used to discuss contributing factors and influences in medicine-taking behaviour, consequences of poor adherence, and strategies to improve medicine adherence, thereby demonstrating the shift towards the concept of concordance.

The literature shows that adherence is a complicated notion, the culmination of the interaction of a variety of aspects such as the features of the condition, social background, access, and patient beliefs and characteristics. Factors that can influence adherence to medicines include gender, age, ethnicity, education, social support, marital status, mood impairment or cognition, number of prescribing doctors, and visiting more than one pharmacy; and it has been found that patients with a higher income and lower medicine expenses tend to be more adherent.

There are several reasons cited for patients not adhering, such as;

  • Forgetting to take the medicine
  • Affordability
  • Concern about safety or effectiveness
  • Fear of or experiencing adverse effects
  • Confusion over the directions
  • No longer feeling unwell or not feeling any different
  • Feeling that they cannot manage with the number of medicines they should take
    and how to coordinate them
  • Having dexterity challenges, or
  • Simply being too unwell.

Adherence to medicines is a variable aspect of treatment, as daily influences impact upon everyday choices, and chronic illnesses involve symptoms, exacerbations, and future impacts, each of which are frequently changing. In a study by Elliott et al (2007) the team concluded that continuing communication with patients about their medicines is necessary, and requires collaboration across disciplines for patients with chronic conditions. In order to positively guide patient decision-making regarding medicine use, health professionals need to be informed of the patients’ current as well as previous choices, as they may place importance on different issues from the prescribers; and with each newly introduced drug the new decisions made by the patient may not always be shared with the prescriber. Hence, when new medicines are initiated, good practice would indicate that a health professional is available to discuss medicines with patients.

Adherence is an important area to consider, as patients are generally poorly adherent to medicines, particularly in chronic disease states. Lack of adherence can lead to medicine wastage, morbidity and hospitalisation. Rates of adherence for a number of chronic medicine regimens have been found to be between 40-50%, and non-adherence is linked to more frequent doctor consultations, and increased rates or duration of hospitalisation. Medicine non-adherence is reported in the literature at a rate of approximately 50% in developed nations, with around half of this proportion being deliberate and the remainder due to ignorance of not taking medicine as they should or due to a complicated regimen.

In a study by Lewis (1997), it was found that sickness due to non-adherence to medicines in the United States costs approximately US$100 billion per year. The National Audit Office reported that returned medicines in England for 2007 approximate to £100 million annually. Noens et al (2009) found that significantly more chronic myeloid leukaemia (CML) patients with an unsatisfactory response had not taken their imatinib (23.2%) compared to those who achieved peak response (7.3% imatinib not taken). In addition, the team found there were significantly fewer missed tablets (9%) in patients who demonstrated a complete cytogenic response, in comparison to the 26% with an incomplete cytogenic response, in a patient group who underwent treatment for a minimum of 12 months with imatinib.

The fact that a disease may possibly be life-threatening does not appear to increase medicine adherence, and findings indicate that adherence can decrease over time. A study by von Mehren and Widmer (2011) found that the population of patients who adhered to imatinib for CML and gastrointestinal stromal tumours decreased from almost 100% during the first four months of treatment to 23% at the fourteenth month. It was also reported that nearly 30% of patients ceased their imatinib for 30 or more days during year one of treatment for CML or gastrointestinal stromal tumours. In another study conducted by Partridge et al (2003), it was shown that long-term adherence to tamoxifen reduced from 83% in the first year of treatment to 50% when the fourth year milestone was reached.

Encouraging open and equal discussion about medicines between both the health professional and the patient leads to improved prescribing practices and better patient adherence. Many studies demonstrate the intervention of a pharmacist enhances medicine adherence rates. Carter et al (2005) report that support networks, the active participation of patients, and advocating self-care are significant contributors to positive treatment outcomes.

Furthermore, patients report an enhanced quality of life when they are contented with the level of information regarding their medicines that is provided to them, and Cassileth et al (1980) similarly mention that patient mechanisms for managing can be derived from the information pharmacists provide.

Concordance refers to a consultative procedure where a collaborative approach between doctor and patient leads to prescribing. Pharmacists can have a role in facilitating this process, thereby alleviating the doctor to focus on diagnosis and formulating a treatment plan. The concordance approach can lead to a more empowered patient as their feelings have been discussed and respected, an open forum encouraged to discuss any ensuing treatment challenges, and hence there is a greater likelihood of the patient following the prescribed treatment and therefore commit to a more transparent decision-making process within which they have played a role.

The philosophy is founded upon delivery of information and viewpoints on the part of the prescriber, and in valuing patient autonomy in reaching decisions rather than imposing directions upon them without further discussion.

Optimising patient outcomes from taking medicine is a multi-faceted concept which relies on the interplay of many ever-changing factors. Ultimately, medicine adherence is founded in an open and trusting relationship between the patient and members of the healthcare team, and the establishment of a positive rapport to foster a team approach involving the patient at the centre.

In order to establish a sincere collaboration, and then a mindfulness of, a pledge to respecting patient autonomy and exercising competent communication skills is required to facilitate the interaction. Greater success in achieving patient adherence may occur by eliciting patient opinions, truly listening to them and assisting them to rationalise difficulties in order to complete the decision-making process, compared to simply dictating how patients should proceed.

References:

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  15. Von Mehren M, Widmer N. Correlations between imatinib pharmacokinetics, pharmacodynamics, adherence and clinical response in advanced metastatic gastrointestinal stromal tumor (GIST): an emerging role for drug blood level testing? Cancer Treat Rev. 2011; 37(4): 291-299.

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