Adherence to medications: Towards a shared ...

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Adherence to medications: Towards a shared understanding Gary Mitchell Patient adherence to medication is a complex issue that is important to patients, health professionals, policy makers and health researchers. This article will provide some background to the phenomenon in relation to adherence, its cost to the health service, how adherence is measured in health research and how concordance and health psychology can aid practitioners in assisting patients in staying adherent to their medication regimens. Key words: Patient compliance; Medication adherence

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he role of a prescriber is multifaceted, but accurate diagnosis of a disorder and subsequent selection of appropriate pharmacological treatment are often believed to be the most important processes involved (Claxton et al, 2001). Effective treatment requires a patient to follow the treatment prescribed at all times (Alexander et al, 2006). Despite this, there is a plethora of literature that suggests that patients do not always strictly observe the medication regimen in place (De Bleser et al, 2009; McMonnies, 2011; Nam et al, 2011).

Defining adherence

With regard to health research, compliance was a term that was used to define the extent to which patients took medication (Burra et al, 2011). Yet the term compliance is now largely out-dated, as it implies a hierarchal relationship between health professional and patient (Bissell et al, 2004). The terms adherence and concordance are now used interchangeably in the literature as a substitute to compliance as, by definition, they promote active cooperation (Blenkinsopp, 2001). Compliance, adherence and Gary Mitchell, nurse and doctoral student, School of Nursing and Midwifery, Queen’s University Belfast [email protected]

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concordance are three terms commonly used in relation to medication-taking, but according to Horne et al (2005) the terms are quite different: ■■ It is commonly held that compliance denotes a passive relationship between patient and health professional, and therefore a patient should follow a prescriber’s orders without question (Bissell et al, 2004; Horne et al, 2005) ■■ Concordance is said to be a partnership, unity or agreement between patient and health professional, whereby the alliance is bolstered through active discussion and choice (Charles et al, 1999; Mead and Bower, 2002) ■■ Adherence is described by Horne et al (2005) as the ‘extent to which the patient’s behaviour matches agreed recommendations from the prescriber’. Therefore, adherence seems to take elements from both concordance, in that there is a degree of freedom and patient choice, and compliance, where the patient is ultimately expected to decide how closely they follow the health professional’s advice, but not necessarily collaborate with the health professional to tailor a personalized medication regime, which concordance has as its central ethos (Royal Pharmaceutical Society of Great Britain, 1997; Charles et al 1999; Mead and Bower, 2002; Garber et

al, 2004; Horne et al, 2005). While the term compliance still appears in health research, it is outdated owing to its paternalistic traits. As illustrated, adherence is a term used to describe patients’ medicinetaking behaviour, while concordance is more complex and places a focus on the interaction between prescriber and patient which usually incorporates some form of shared decision-making.

The importance of adherence According to three systematic reviews, non-adherence to medication is estimated to affect approximately 20–60% of patients, with the highest rates occurring in chronic conditions (Higgins and Regan, 2004; Kripalani et al, 2007; Garfield et al, 2011). Unsurprisingly, this non-adherence leads to higher hospitalization rates, increased healthcare costs and poorer health outcomes (World Health Organization (WHO), 2003). Elliot (2009) demonstrated this through statistical analysis warning that nonadherence leads to an 80% increased risk of death in diabetic care, an almost 50% increase in asthma mortality and around a four-fold increase in death post-myocardial infarction. In terms of economic cost, Trueman et al (2010) state that in the UK, medicines are the biggest expenditure after staffing and more alarmingly, more than £300 million worth of medications is wasted annually. Importantly, health professionals should realise that patient non-adherence to medications may not always be intentional. By virtue of this knowledge, all health professionals have a duty of care to their patients to ensure they provide adequate education to

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patients in relation to their medication regimen (Horne et al, 2005).

Measurement of medication adherence The most effective method of adherence measurement is systematic observation (Garfield et al, 2011). While this method is undoubtedly accurate, it is very seldom utilized in health research, mainly because of its intrusive and impractical nature. Observation of every patient could also give rise to what is termed the Hawthorne effect (Parahoo, 2006; Burns and Grove, 2009 and Polit and Beck, 2009). The Hawthorne effect is the realization that through researcher observation, a participant can modify their behaviour in a way that positively benefits the study (Polit and Beck, 2009). There is much debate about the most effective way of measuring adherence. There are two main schools of thought. Some champion direct methods such as electronic monitoring devices (EMDs), pill counts and measurement of a drug or metabolite in the blood. While others prefer indirect methods such as interview, questionnaire or self-reported diaries (Osterberg and Blaschke, 2005). These two types of methods will now be examined in greater detail.

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Direct monitoring According to Claxton et al (2001), the EMD examines medication adherence using special containers that store dosing information on a microchip. Therefore, each time a patient takes off the medication lid, the chip records information. This measurement is utilized in many studies (Berg et al, 1998; Horne et al, 2005; Burra et al, 2011). Despite the obvious flaw—a patient only has to remove a medication lid and not ingest it to be recorded as adherent—this method is frequently deemed the ‘gold standard’ with regards to measurement of adherence (Horne et al, 2005). A similar method for assessment of adherence closely allied to EMD is pill counting (MacLaughlin et al, 2005). Yet despite its simplicity, this method has been shown to overestimate medication adherence (Murray et al, 2004). In a Nurse Prescribing 2014 Vol 12 No 11

The most effective method of adherence measurement is systematic observation study of diabetic patients using oral agents, pill counts are inconsistent when tested alongside EMD monitoring: a possible reason for this is ‘over adherence’ or ‘pill dumping’ in the days leading up to consultation (Paes et al, 1998). While Kee et al (2006) and Karch (2008) would acknowledge that measurement of blood, urine or plasma concentration is sometimes useful in assessment of adherence in specific drug regimes; they would also caution that even these methods can be erroneous. In a review carried out by MacLaughlin et al (2005), it was unearthed that various studies that opted to undertake this line of investigation found that ‘pill dumping’ in the days leading up to consultation and measurement produced a higher than usual concentration of drug in the body and so masked nonadherence. With regard to practical pharmacokinetics, McGavock (2005) suggests that every individual’s level of drug clearance is unique as it is dependent on a great number of factors and so is not free from criticism. These direct approaches can be subject to manipulation by the patient. While it has been argued that the EMD holds the title of gold standard, many other authors contend that as of yet no gold standard exists in the field of measuring adherence to medication (Wagner et al, 2001; Alcoba et al, 2003; Murray, 2004; Osterberg and Blaschke, 2005).

Indirect monitoring Many studies that were identified in the literature sought to measure medication adherence, which is effectively achieved by the direct methods outlined above. Yet indirect methods, when utilized effectively, can aid researchers in understanding the rationale behind non-adherence. Self-report through semi-structured interview is considered an appropriate method of monitoring. While disadvantages exist in the form of patients overestimating their adherence to treatment (Horne et al, 2005; Garfield et al, 2011), it is regarded as an appropriate tool for clinical practice, especially in the domain of subjective understanding of the phenomenon (National Institute for Health and Care Excellence (NICE), 2009). Garfield et al (2011) support NICE (2009) guidelines and state that on a practical level, research must be cost-efficient, unobtrusive and easily repeated. While a meta-analysis from Shi et al (2010) proposed that self-reporters frequently overestimated their actual medication adherence when trialled alongside other direct methods, the strength of self-reporting lies in the ability to understand and fashion reason. Selfreport, or interviewing, can distinguish between intentional and unintentional non-adherence and empowers the patient to collaborate with the health professional 565

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and provide recommendations to improve the future care of other patients.

Improving adherence and concordance There have been many tactics adopted by health professionals in a bid to not only enhance medication adherence, but also to understand the logic behind nonadherence. An effective strategy that is prevalent in the literature involves simple dosing regimens. It is held that the reduction of doses frequently results in increased adherence (Iskedjian et al, 2002; Richter et al, 2003). While this simplicity benefits the regimen, it does not always guarantee success. Yildiz et al (2004) found that adherence to antidepressant medication was not increased despite the introduction of a one-off dosing regimen, although success has been reported in many other studies as evidenced by van Dulmen et al’s (2007) meta-analysis. Communication between the health professional and patient is an important element in maximizing rates of adherence. This is recognized in the ideology of concordance, which places a huge emphasis on two-way communication and shared decision-making about medications (Royal Pharmacology Society of Great Britain, 1997). While adherence and concordance are different concepts (adherence is purely outcomes based and concordance is recommended conduct), they are intrinsically linked. The notion of concordance implies collaboration and partnership, and this in itself promotes adherence to medication (MeystreAgustoni et al, 2000). The rationale for this is quite simple, if a patient understands their medical condition, is made aware of the importance of their medication and afforded the opportunity to be part of the decision-making process, they are more likely to take ownership of their current and future healthcare (Royal Pharmacology Society of Great Britain, 1997). Further techniques that were shown to benefit medication adherence included telephone services, in which a patient could contact the clinic with specific queries (Kelly et al, 1999), when a patient had written down questions prior to a consultation (Barnett et al, 2000), and 566

interaction with a pharmacist (Blenkinsopp et al, 2000; Raynor et al, 2000). The focus of these methods, which were adopted to improve patient adherence, was the importance of good two-way communication (Stevenson et al, 2004).

Behaviour and patient belief variables According to MacLaughlin et al (2005), patients’ knowledge and beliefs about their medication regimen and disease play a very significant role in therapy adherence. Patients who understand their disease and the need for medical intervention are more likely to thrive and adhere as opposed to those who do not (van Dulmen et al, 2007). One form of behaviour that can be seen in patients who do not regularly adhere to medication regimens is ‘white coat adherence’. White coat adherence is a phenomenon that has been observed in the literature, whereby patients increase their level of adherence in the days leading up to consultation in a bid to be considered a ‘good patient’ (McLaughlin et al, 2005). Further terminology relating to specific non-adhering behaviour is that of a ‘drug holiday’. A drug holiday is the intentional omission of medication for a period of time. The motivation for this behaviour is specific to the patient and is probably best identified during consultations using good two-way communication between the patient and the health professional. While the rationale for ‘white coat adherence’ or ‘drug holidays’ is unclear, it most likely occurs in patients who are prescribed long-term therapies. With this in mind, some patients may believe that missing a few doses will not matter as they have, and will continue to, take the medications for a prolonged period of time (McLaughlin et al, 2005). Knowledge of these behaviours is useful in understanding the complexity of adherence, but owing to the subjective nature of behaviour, some authors advocate the use of a behavioural theory or model to assist practitioners in understanding and improving adherence (Naidoo and Wills, 2000). There are several models that can be used to understand adherence. Stages of change model The stages of change model (Prochaska and DiClemente, 1984) is extremely

useful in understanding how a person changes. The stages of change model can help explain or predict a person’s success or failure in achieving a proposed behaviour change, such as adhering to oral medication. The stages of change model can be of benefit to the health professional when planning an intervention with a patient. Crucially, the model illustrates that a patient undergoing behaviour change does not follow a linear path from start to finish but is part of an ongoing cycle. Notably, a patient or client can move backwards or forwards in the model (Niven, 2000). The first stage in Prochaska and DiClemente’s model is termed the precontemplation stage. In this stage a patient has not yet considered or recognized a need for a change in their behaviour. The second stage in the model is referred to as the contemplation stage. In this stage Prochaska and DiClemente note that an individual is often ambivalent, on one hand recognizing the benefit of change and on the other hand aware of the costs of change. When a client or patient decides to make a behavioural change, they move onto the preparation stage. At this stage the client perceives behaviour change as worthwhile and that the benefits outweigh the costs. The action and maintenance stage soon follow. In the action stage a client actively begins their behaviour change. If behaviour change has truly occurred, the patient then moves on to maintenance. At this stage, behaviour change is sustained and self regulation is prominent in the patient (Walker et al, 2004). The patient must continue to be aware of relapse triggers and perhaps discuss the probability of developing new behaviours in high-risk situations. The relapse stage is common in the stages of change model. A relapse can happen at any stage in the model and can even lead to a termination of behavioural change. Success in Prochaska and DiClemente’s model is variable and effective communication among other things can improve its success (Naidoo and Wills, 2000). Self-efficacy model While the stages of change model (Prochaska and DiClemente, 1984) has been utilized in studies specific

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to the topic of medication adherence (Garfield and Caro, 1999; Willey et al, 2000; Ficke and Farris, 2005), this model cannot, as Garfield et al (2011) warn, explain unintentional causes of nonadherence. These non-intentional causes of adherence cannot be assessed through conventional models, but instead through personalized interaction with the patient. Self-efficacy was coined by Bandura (Naidoo and Wills, 2000; van Dulmen et al, 2007) as part of his social cognitive theory. A person’s self-efficacy is influential in adapting a new behaviour. Self-efficacy is defined as the extent to which people believe they are competent to confront the challenges of life (Niven 2000). In a patient with high self-efficacy, there is self-confidence in their ability to achieve what is wanted or needed. It is important to note that people with high self-efficacy are generally of the opinion that what they do or don’t do can affect their health. On the contrary, clients with very low self-efficacy may see their health as pre-determined and are more likely to oppose certain medical treatments (Mason and Whitehead, 2003; Ficke and Farris, 2005). The concept of self-efficacy can be viewed alongside the stages of change model, because the lower a patient’s self-efficacy, the lower the chance of continued maintenance in the stages of change model and the more likely a relapse will occur (Haukkala et al, 2000). Self-efficacy is a predictive tool that can be used when considering the patient about to commence drug therapy. It is worth noting that through collaboration with the multi-disciplinary team, selfefficacy can be improved through education (Murray et al, 2004; Garfield et al, 2011). The application of medication adherence to these examples is difficult, as ultimately behavioural change theories are often utilized in the context of smoking cessation and weight loss. Serial non-adherers may best be managed and supported through the stages of change model, but it should not be assumed that all patients purposely non-adhere. Indeed, Murray et al (2004) developed a conceptual framework that took into account environmental, healthcare and patient characteristics factors in an Nurse Prescribing 2014 Vol 12 No 11

attempt to understand adherence in older populations, as opposed to the adoption of an already-existing model. From the literature unearthed, few researchers consider concordance alongside behavioural theory. Patient activation measure One model that does consider behavioural theory, and as such is particularly useful for practitioners, is the patient activation measure (PAM) (Hibbard et al, 2004). The PAM assesses patient knowledge and level of confidence in relation to the active management of their health. Patients who score high on PAM are much more likely to understand and be able to take an active role in managing their health and understand when they should seek health professional interaction. For patient activation to occur, health professionals must facilitate the completion of four stages: ■■ 1. Recognition that the patient is important in the process ■■ 2. Provision of knowledge so that patients can have confidence and knowledge to take necessary direction ■■ 3. Empowering patients to actually take action and adhere to medication regimen ■■ 4. To support patients and ensure they can continue regimen even when under stress. Patients who are more ‘activated’ are more likely to engage in positive health behaviours, such as attending appointments, taking regular exercise, maintaining a healthy weight and, with specific reference to medication-taking, remaining adherent. In patients who are ‘less activated’, the converse is true and thus health-related outcomes decrease (Hibbard et al, 2004).

Conclusion

Appropriate adherence to medication is understandably an important component of healthcare. All health professionals (nurses, pharmacists and physicians) play an important role in providing information about medicines to their patients; however, this does not always ensure adherence. Indeed, the literature around this topic seems to indicate that practitioners who engage in concordant practices, and therefore

involve the patient in decisions about medicines, are likely to have patients with higher rates of adherence. Caring for the patient as a person is nothing new in healthcare research and its importance is also validated in this article. Patients who are empowered to take responsibility of their care (with health professional support) are more likely to not only adhere to their medications, but also enabled to positively shape their care in the future. Alcoba M, Cuevas MJ, Perez-Simon MR et al (2003) Assessment of adherence to triple antiretroviral treatment including indinavir: role of the determination of plasma levels of indinavir. J Acquir Immune Defic Syndr 33(2): 253–8 Alexander MF, Fawcett JN, Runciman PJ (eds) (2006) Nursing Practice Hospital and Home; The Adult. 3rd edn. Churchill Livingstone, Edinburgh Barnett C, Nykamp D, Ellington A (2000) Patientguided counseling in the community pharmacy setting. J Am Pharm Assoc (Wash) 40(6): 765–72 Berg J, Dunbar-Jacob J, Rohay JM (1998) Compliance with inhaled medications: the relationship between diary and electronic monitor. Ann Behav Med 20(1): 36–8 Bissell P, May CR, Noyce PR (2004) From compliance to concordance: barriers to accomplishing a reframed model of health care interactions. Soc Sci Med 58(4): 851–62 Blenkinsopp A, Phealen M, Bourne J, Dakhil N (2000) Extended adherence support by community pharmacists for patients with hypertension: a randomised controlled trial. Int J Pharm Pract 8(3): 165–75 Blenkinsopp A (2001) From compliance to concordance: how are we doing? Int J Pharm Pract 9(2): 65–6 Burns N, Grove S (2009) The Practice Of Nursing Research: Appraisal, Synthesis And Generation Of Evidence. 6th edn. Saunders Elsevier, St. Louis Burra P, Germani G, Gnoato F, Lazzaro S, Russo FP, Cillo U, Senzolo M (2011) Adherence in liver transplant recipients. Liver Transpl 17(7): 760–70. doi: 10.1002/lt.22294 Charles C, Gafni A, Whelan T (1999) Decisionmaking in the physician-patient encounter: revisiting the shared treatment decision-making model. Soc Sci Med 49(5): 651–61 Claxton AJ, Cramer J, Pierce C (2001) A systematic review of the associations between dose regimens and medication compliance. Clin Ther 23(8): 1296–310 De Bleser L, Matteson M, Dobbels F, Russell C, De Geest S (2009) Interventions to improve medication-adherence after transplantation: a systematic review. Transpl Int 22(8): 780–97. doi: 10.1111/j.1432-2277.2009.00881.x Elliott R (2009) Non-adherence to medicines: not solved but solvable. J Health Serv Res Policy 14(1): 58–61. doi: 10.1258/jhsrp.2008.008088

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