Drugs Aging (2014) 31:149–157 DOI 10.1007/s40266-014-0153-9
LEADING ARTICLE
Intentional Non-Adherence to Medications by Older Adults Omar Mukhtar • John Weinman Stephen H. D. Jackson
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Published online: 25 February 2014 Springer International Publishing Switzerland 2014
Abstract ‘The extent to which an individual’s medication-taking behaviour and/or execution of lifestyle changes, corresponds with agreed recommendations from a healthcare provider’, is a highly complex behaviour, defined as adherence. However, intentional non-adherence is regularly observed and results in negative outcomes for patients along with increased healthcare provision costs. Whilst this is a consistent issue amongst adults of all ages, the burden of chronic disease is greatest amongst older adults. As a result, the absolute prevalence of intentional non-adherence is increased in this population. This non-systematic review of intentional non-adherence to medication highlights the extent of the problem amongst older adults. It notes that age, per se, is not a contributory factor in intentionally non-
O. Mukhtar (&) Clinical Pharmacology and Therapeutics, King’s Health Partners, King’s College Hospital, Denmark Hill, London SE5 9RS, UK e-mail: [email protected] J. Weinman Institute of Psychiatry, King’s College London, London, UK S. H. D. Jackson Department of Clinical Gerontology, King’s Health Partners, London, UK
adherent behaviours. Moreover, it describes the difference in methodology required to identify such behaviours in contrast to reports of non-adherence in general: the use of focus groups, semi-structured, one-to-one interviews and questionnaires as opposed to pill counts, electronic medication monitors and analysis of prescription refill rates. Using Leventhal’s Common-Sense Model of Self-Regulation, it emphasizes six key factors that may contribute to intentional non-adherence amongst older adults: illness beliefs, the perceived risks (e.g. dependence, adverse effects), benefits and necessity of potential treatments, the patient–practitioner relationship, inter-current physical and mental illnesses, financial constraints and pharmaceutical/ pharmacological issues (poly-pharmacy/regimen complexity). It describes the current evidence for each of these aspects and notes the paucity of data validating Leventhal’s model in this regard. It also reports on interventions that may address these issues and explicitly acknowledges the lack of evidence-based interventions available to healthcare practitioners. As a result, it highlights five key areas that require urgent research amongst older adults: (1) the overlap between intentional and unintentional non-adherence, particularly amongst those who may be frail or isolated; (2) the potential correlation between symptomatic benefit and intentional vs. unintentional non-adherence to medication; (3) an evaluation of the source of prescribing (i.e. a long-standing provider vs. an acute episode of care) and the patient–prescriber relationship as determinants of intentional and unintentional non-adherence; (4) the decision-making processes leading to selective intentional nonadherence amongst older adults with multiple medical problems; and (5) the development and evaluation of interventions designed to reduce intentional non-adherence, specifically addressing each of the aspects listed above.
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Key Messages Intentional non-adherence represents a significant issue, particularly amongst older adults. Our understanding of the factors that lead to intentional non-adherence amongst older adults is limited and requires further research. Researchers must also develop and evaluate interventions that address these causative and contributory factors, relating them both to intentional adherence and to clinical outcomes.
1 Introduction The last 50 years has witnessed an unprecedented increase in the number of evidence-based healthcare interventions, e.g. lifestyle changes, pharmacological agents and operative/interventional procedures. As a result, professionals working in this field are often able to make recommendations to patients seeking medical advice, which may improve their symptoms and/or prognosis. However, the failure to follow such recommendations may jeopardise the patient’s health and well-being, frustrate the healthcare professional(s) involved and lead to a considerable waste of resources [1]. Although it may be unintentional, this is often not the case—a number of studies have shown that intentional non-adherence comprises approximately 50 % of all non-adherent behaviours observed amongst those over the age of 65 years [2]. Despite this and despite knowing that patients rarely volunteer such information, the issue of intentional non-adherence is all too frequently ignored by healthcare professionals—half of all general practitioners admit that they would like to confront their patients about the issue, but feel unable to do so [3]. This non-systematic review seeks to address this issue, with reference to older adults (aged over 65 years). It looks beyond the biomedical approach and adopts Leventhal’s Common-Sense Model of Self-Regulation [4] in an effort to describe the causes of intentional non-adherence and measures that may limit its occurrence. In doing so, it highlights important research questions, which have yet to be explored. In March 2011, a non-systematic literature search was conducted using PubMed (http://www.ncbi.nlm.nih.gov/ pubmed), MEDLINE and the Cochrane Database of Systematic Reviews; this was repeated in October 2013. The search prioritised studies published in the last 10 years and only included those available in the English language; however, older studies considered to be important by individual authors were also included, as was guidance
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from the National Institute for Health and Care Excellence. Further relevant references were selected from the bibliographies of identified papers. Key search terms (including combinations thereof and non-hyphenated versions) were: intentional, deliberate, non-adherence, non-compliance, non-concordance, elderly, older adults, geriatrics, medications, interventions and health psychology.
2 Compliance, Concordance, Adherence and Persistence Any review of intentional non-adherence would be incomplete without defining the terms compliance, adherence, concordance and persistence. Indeed, the term used to describe medication use as recommended by a doctor or other healthcare professional has been the subject of much discussion. Compliance is widely defined as ‘the extent to which a patient’s behaviour coincides with the prescriber’s recommendations’ [5]. However, the term has been criticised for its paternalistic implications, with the patient ‘‘passively following the prescriber’s orders’’ [5]. Furthermore, when discussing the issue of ‘non-compliance’, various groups have suggested that the term attributes blame to the patient [6, 7]. Adherence, ‘the extent to which a person’s medication-taking behaviour and/or execution of lifestyle changes, corresponds with agreed recommendations from a healthcare provider’ is considered by some to be more acceptable [8]. This is because it is thought to recognize the autonomy of the patient whilst emphasizing the patient’s agreement with the suggested recommendations [9]. Others have advocated the use of the term concordance, because of a belief that it reflects a more patient-centred approach—in this instance, healthcare professionals make a therapeutic alliance with the patient, in an effort to respect the patient’s wishes and beliefs about the treatment/intervention in question [9]. However, this descriptor provides no indication as to whether a treatment/intervention is followed. More recently, the term persistence has also been used in this field; this refers to the act of continuing a treatment for the prescribed duration and has been defined as ‘‘the duration of time from initiation to discontinuation of therapy’’ [10]. Those favouring this term highlight the fact that clinical outcomes are dependent upon both adherence and persistence; addressing both of these factors provides for a more complete understanding of medication-taking behaviour [10]. However, we believe that the principle of persistence is encompassed within the term adherence; the degree to which medication-taking behaviour and/or execution of lifestyle changes correspond with the agreed recommendations from a healthcare provider, implicitly includes a temporal aspect. Thus, the consensus of opinion
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amongst researchers, healthcare professionals and the World Health Organization favours the term adherence, which will be the preferential term for the purposes of this review [8, 11].
3 Intentional vs. Unintentional Non-Adherence? Historically viewed as a homogenous entity, non-adherent patient behaviours are increasingly divided into unintentional or intentional [12–15], with a small, but growing number of studies acknowledging that there may be an overlap between the two [16–18]. Unintentional non-adherence describes a situation where patients fail to follow a recommended therapeutic/healthcare-based intervention, without making a conscious decision [18, 19]. Thought of as a passive process on the part of a patient, it frequently encompasses inadvertent forgetfulness and an inability to follow treatment instructions because of a lack of understanding or physical problems, e.g. poor eyesight or impaired manual dexterity [18, 19]. In contrast, intentional non-adherence occurs when a patient consciously elects not to follow the measures recommended by a healthcare professional—it is best defined as an active decision on the part of patients to forego (discontinue, skip or alter) prescribed therapy [18, 19]. However, patients can, and do, exhibit both types of non-adherent behaviour, often at the same time—a finding observed amongst both older adults and their younger peers [15–17, 20]. Thus, whilst this non-systematic review highlights the issue of intentional non-adherence amongst older adults, it is important to acknowledge that a dichotomous approach (intentional vs. unintentional non-adherence) may not be all encompassing.
4 Intentional Non-Adherence in Older Adults: An Issue Worthy of Consideration? Our understanding of intentional non-adherence is further complicated by our inability to accurately record adherence using a widely accepted gold standard. The most commonly used techniques include a review of prescription records, self-reporting and pill-counts [21]. All three methods are problematic, particularly self-reporting, which is subject to recall bias and a reluctance on the part of patients to acknowledge non-adherence [21]. Medication measures, such as prescription ordering and prescription filling, represent an active first step toward taking a medication; however, they too are subject to error and manipulation as the possession of a medication does not equate to ‘… the extent to which a person’s medication-taking behaviour … corresponds with agreed recommendations
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from a health care provider’ [8, 22, 23]. Electronic monitoring of adherence-related events, e.g. the opening of a pill bottle or the depression of an inhaler, is prone to similar issues—despite being regarded by some as close to a goldstandard measure [24]. Although the above measures may delineate adherence from non-adherence, they offer little insight with regard to the specific issue of intentional non-adherence (Table 1). In an effort to explore this specific issue, researchers have thus far drawn upon a range of qualitative research techniques including questionnaires (e.g. the Beliefs about Medicines Questionnaire-Specific), focus groups and semistructured interviews [7, 25–29]. However, these methods are equally problematic, in that they are reliant upon candour from the respondent. Given such methodological issues, our need to understand non-adherence would be minimised were it not a sizeable problem with significant sequelae; however, the World Health Organization estimates that only 50 % of patients with a chronic disease will take their medication as agreed and the direct and indirect costs of non-adherence, in the US alone, are estimated at $US100 billion per year [8, 30]. With adults over the age of 65 years twice as likely to receive prescribed therapy compared with their younger counterparts [31], this issue is of greatest importance amongst older adults, in whom non-adherent behaviours have been associated with declining health, increased healthcare costs and increased hospital admissions [32–36]. In one study, 32 % of all medication-related attendances to the emergency department resulted from non-adherence [35]. Furthermore, the issue of intentional non-adherence is particularly worthy of consideration in older adults as a number of studies have indicated that between 33 and 75 % of all non-adherence in older adults is either exclusively or in part intentional [2, 37, 38]. Prior to further considering the issue of intentional nonadherence, it is important for readers to note that although advancing age may be associated with an accumulation of chronic disease for some, functional decline for others and increased rates of cognitive impairment, there are inconsistent data with regard to its role in non-adherence. A
Table 1 Methods evaluating intentional non-adherence Measures to evaluate intentional non-adherence Face-to-face, individual interviews Group interviews Focus groups Questionnaires, e.g. Beliefs About Medication Questionnaire, Reported Adherence to Medication Scale, Discrete choice experimentation Narrative exploration
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number of studies have suggested that older adults may demonstrate increased rates of adherence when compared with their younger counterparts [39–43]; others have demonstrated no effect or decreased adherence rates [44, 45]. Although such variations may be attributable to methodological differences, differences in the thresholds used to define older adults and geographical location, the inconsistent nature of the data challenges the populist view that older adults are more likely to exhibit non adherence, per se.
5 Explaining Intentional Non-Adherence: Insights from Health Psychology The traditional medical model provides one interpretation of intentional non-adherence amongst older adults [8]. However, health psychology offers an alternative, potentially comprehensive, patient-centred approach that is considered here. Early psychological attempts to explain non-adherent and adherent behaviours focused on selected personality traits [46]—whilst a number of descriptors were identified, e.g. conscientiousness (purposeful, well organised, selfdisciplined behaviours) this approach consistently failed to explain why individual patients demonstrate adherence to some medications and not others [46, 47]. As a result, health psychologists have drawn upon more sophisticated
models of human behaviour to explain and modify nonadherence. These include the Health Belief Model [48], the Theory of Planned Behaviour [49] and the Trans-Theoretical Model [50]. However, it is the Common-Sense Model of Self-Regulation (varyingly known as the Illness Perceptions Model, the Illness Representations Model, the Self-Regulatory Model and the Parallel Process Model) developed by Leventhal and colleagues [4], which unifies many of the themes engendered in these theories, from the perspective of a patient. The Common-Sense Model of Self-Regulation proposes that all threats to health (including illness) pose a challenge to an individual’s sense of self and their key goals; as a result, the individual actively attempts to make sense of these threats to minimise their impact [4]. This is achieved at both a cognitive and emotional level by developing representations (understanding), which duly generate behavioural responses (e.g. deciding to seek medical help, following medical advice). At the core of the individual’s representation (or understanding) of their problem are a number of related beliefs about the nature of the problem [4]. Thus, on experiencing a new symptom, the individual will typically label or describe that which they experience, linking it with other symptoms that they are experiencing/ have experienced in the past. These aspects constitute their perceived identity of the problem; this is typically linked with a causal explanation, as well as expectations about how long the problem will last (time-line), its likely effects
Table 2 Interventions addressing intentional non-adherence Factor
Intervention
Illness beliefs:
The published literature does not provide evidence of any specific interventions in older adults that have sought to modify illness beliefs in an effort to improve intentional non-adherence
Treatment beliefs:
There are no formal studies in the literature evaluating interventions in older adults that address the issue of treatment beliefs, where intentional non-adherence serves as the primary outcome measure A number of randomised controlled trials evaluating medicines reviews in older adults (aged [65 years) have demonstrated significantly increased adherence rates; however, the results are not entirely consistent, as other studies have reported no statistical difference [89]. Whilst the reviews varied widely in content and structure, knowledge of medicines was a feature of all interventions (see pp. 294–302 of NICE guidelines for more details) [89]
The patient–practitioner relationship:
No studies have sought to evaluate the effectiveness of an improved patient–practitioner relationship upon intentional non-adherence amongst older adults: the NICE guidelines on medicines adherence similarly report that no clinical tools have been evaluated that might aid a practitioner in establishing patient– practitioner congruence with regard to medicines [89]
Poly-pharmacy/regimen complexity
The published literature is notable for the absence of interventions in older adults that address the issue of poly-pharmacy and regimen complexity, with intentional non-adherence a documented outcome measure. A number of studies evaluating medicines reviews, sought to rationalize and simplify medicine regimens—the reported outcomes were mixed, with some studies demonstrating significantly increased adherence rates and others reporting no statistical difference. However, the focus remained on adherence in general, as opposed to intentional non-adherence [89]
The perception of self (intercurrent illnesses) Cost
There are no published interventions that have specifically sought to evaluate the treatment of inter-current illnesses in an effort to improve intentional non-adherence amongst older adults No specific interventions countering the effect of increased co-payments/cost have been evaluated in older adults, who exhibit intentional non-adherence
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(consequences) and the extent to which it is amenable to cure or control by the individual and others, e.g. healthcare professionals. Ultimately, these representations will influence how the individual responds to their initial symptoms, to the results of any subsequent investigation and to any recommended treatment or advice [4]. Using this model, it is possible to theorise that a number of factors may contribute to intentional non-adherence amongst older adults. These include illness beliefs and the perceived risks (e.g. dependence, adverse effects) and benefits of potential treatments—in turn, these may be influenced by external factors (e.g. interactions with healthcare professionals). Inter-current physical and mental illness may impact upon the perception of self and thus alter the degree of intentional non-adherence, whilst financial constraints and polypharmacy may also influence the goals of individual adults. 5.1 Illness Beliefs Using a cross-sectional survey, Rajpura et al. [51] demonstrated a significant and positive correlation (r = 0.332; p = 0.001) between medication adherence in general (measured using Morisky’s questionnaire) and illness perception scores (as assessed by a modified Brief Illness Perception Questionnaire) in older adults with hypertension. Similarly, Sofianou and colleagues [52] have demonstrated that self-reported non-adherence was more frequently observed amongst older adults with erroneous beliefs about asthma than those with appropriate illness perceptions. Although such studies demonstrate that illness beliefs influence overall adherence in older adults, the published literature is not explicit about the impact this factor has upon intentional non-adherence in older adults [51–54], thus warranting further investigation (Table 3). Nonetheless, such a relationship is intimated by the work of Lindquist et al. [12] who observed that older adults with adequate health literacy were significantly more likely to exhibit intentional non-adherent behaviours, when compared to those with inadequate and marginal health literacy. 5.2 Treatment Beliefs: Adverse Effects, Necessity and Efficacy Numerous studies have shown that perceptions relating to treatment play a critical role in influencing levels of nonadherence amongst patients of all ages [13, 29, 37, 55–62]. These can be broadly categorised into two; (1) the perceived necessity and efficacy of a treatment and (2) concerns relating to potential adverse effects, regardless of whether or not these can be scientifically validated [13, 29, 37, 55–62].
153 Table 3 Suggestions for future studies Further evaluation of the overlap between intentional and unintentional non-adherence, particularly amongst those who may be frail or isolated Detailed evaluation of the potential correlation between symptomatic benefit and intentional vs. unintentional nonadherence to medication Evaluation of the source of prescribing (i.e. a long-standing provider vs. an acute episode of care) and the patient–prescriber relationship as a determinant of intentional and unintentional non-adherence Evaluation of the decision-making processes leading to selective intentional non-adherence amongst older adults with multiple medical problems The development and evaluation of interventions designed to reduce intentional non-adherence amongst older adults
Looking specifically at older adults, Fried et al. performed interviews with 356 community-dwelling adults. Participants were asked about their willingness to take medication for the primary prevention of a myocardial infarction with varying degrees of benefit (absolute 5-year risk reduction) and harm (type and severity of adverse effects). Eighty-eight percent of those interviewed would take medication providing an absolute benefit of six fewer infarcts out of 100, approximating the average risk reduction of currently available medications. Eighty-two percent of participants who would take it remained willing to do so were the absolute benefit decreased by 50 %. In contrast, 69 % were unwilling or uncertain about taking such medication were it to cause mild adverse effects (e.g. fatigue, nausea); only 3 % would take medication with adverse effects severe enough to affect activities of daily living. Thus, the authors concluded that the willingness of older adults to take medication for primary cardiovascular prevention is relatively insensitive to its benefit but highly sensitive to adverse effects [29]. Using a study population primarily (78 %) over the age of 60 years, Ratcliffe and colleagues [59] demonstrated that patients are more likely to be concerned about the risk of relatively rare but serious adverse effects than relatively common, mild adverse effects. Similarly, Grant et al. [60] demonstrated that a population of older adults (mean age: 66 years) in receipt of multiple medications, were more likely to demonstrate nonadherence to those medicines not felt to be improving current or future health (6.1 vs. 6.9 days out of 7, p \ 0.001), when compared with those perceived to have long-term benefits. How such data relate to intentional non-adherence amongst older adults in everyday clinical practice is difficult to quantify, particularly in light of two important studies. Using a mixed study population of Japanese adults (age range 0–79 years; 64 % aged over 60 years) Iihara et al. [13] demonstrated that the perception of benefit was not associated with intentional non-adherence (although it was associated with unintentional adherence behaviours);
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the reliability of a translated European scale to assess beliefs about adverse effects and their impact upon intentional adherence was poor, thus negating this aspect of the study. In contrast, Schu¨z et al. [61, 62] demonstrated that increases in specific necessity beliefs predicted improved intentional adherence to medication using a study population consisting entirely of older adults (aged 65–85 years); the belief that a medication was harmful predicted a greater likelihood towards intentional non-adherence.
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median age of 65 years) is associated with decreased adherence to statin therapy; Schu¨z et al. [62] observed that a greater number of illnesses was associated with increased concern about pharmacological treatment amongst adults aged 65–85 years. How such studies relate to intentional non-adherence is unclear. 5.5 Cost
As anticipated from the earlier, brief analysis of the Common-Sense Model of Self-Regulation, a number of factors external to the patient may have the potential to affect intentional non-adherence. One such factor is the patient–practitioner relationship, where a shared understanding (or representation) of the illness and treatment does not exist. A considerable body of research suggests that healthcare practitioners are directly able to influence the degree of non-adherence [28, 37, 63–68], with ‘personable’ prescribers likely to achieve greater rates of adherence compared with those deemed to be ‘business-like’ (61 vs. 35 %) [64]. Moreover, a congruence of vocabulary between patient and prescriber is known to correlate with the intention to adhere [65]. However, only a few of these studies focus on older adults [28, 55, 69] and none aim to correlate the patient–practitioner relationship with intentional adherence in older adults—thus identifying a further important gap in the published literature (Tables 2 and 3).
Much of the early research relating to the cost of medicines sought to correlate this variable with the use of medicines in older adults—in contrast to adherence and non-adherence, ‘use’ is an umbrella term that includes the prescription, supply and utilisation of medicines in a society [73]. However, there is now a growing body of evidence that suggests that economic considerations directly impact adherence amongst older adults [74–78]. Commercial insurers, in the US, reported a decrease in medication possession ratios (the percentage of time a patient has access to medication) as the copayment for ACE inhibitor use rose from $US5 to $US30 [76]; similarly, the Veterans Association found that the absolute difference in medication availability decreased by 7 % when co-payments were increased from $US2 to $US7, with an additional 12 % of patients experiencing undesirable treatment lapses of C3 months [77]. Moreover, a recent metaanalysis demonstrated an 11 % increase in the likelihood of non-adherence to medicines in publicly insured populations (mean age: 71.75 years) where co-payments are necessary; however, none of the studies included in the meta-analysis explicitly sought to determine whether cost/co-payment influences intentional or unintentional adherence [75].
5.4 The Perception of Self: Inter-Current Illness
5.6 Regimen Complexity and Polypharmacy
According to Leventhal’s model [4], those factors that alter an individual’s sense of self may also influence the degree of intentional non-adherence observed. Di Matteo et al. [70] reported that anxiety was not significantly associated with non-adherence; in contrast, depressed patients were three times more likely to exhibit non-adherent behaviours when compared with those who were not depressed (odds ratio: 3.03; 95 % confidence interval [CI]: 1.96–4.89). However, this meta-analysis, based on observational studies, did not focus on older adults or on intentional non-adherence and the subsequent literature has failed to address this specific question; thus highlighting a further focus for future studies (Table 3) [70]. Nonetheless, in 2013, Sundborn and Bingefors [71] demonstrated that symptoms of anxiety and/or depression were associated with both unintentional and, to a greater extent, intentional non-adherence—albeit in a mixed population, of which only 22 % of the 4,709 respondents were aged 65 years or over. More widely, Calip et al. [72] observed that breast cancer (in a population of women with a
A large meta-analysis by Claxon et al. demonstrated that increasing dose frequency correlated with declining adherence in patients, regardless of age [79]—in older adults (aged over 64 years), the use of at least one drug requiring multiple daily dosing is significantly associated with medication non-adherence (odds ratio: 2.99; 95 % CI: 1.24–7.17) [80]. Moreover, the conjunction of different medicines, such that they are taken collectively at one time point (polypharmacy) by older adults, may reduce adherence [47, 63, 81, 82]. However, such a correlation is not unequivocal—Corsonello et al. [80] were not able to demonstrate this relationship in older adults, whilst others have demonstrated that older adults prescribed greater numbers of tablets were more likely to demonstrate adherence [83]. Nonetheless, there is evidence that patients exhibit selective non-adherence when they are in receipt of multiple medications. A survey of 128 patients (mean age ± standard deviation: 66 ± 11.7 years) with diabetes
5.3 The Patient–Practitioner Relationship
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mellitus, undertaken in 2003, indicates that patients with suboptimal overall adherence tend to have problems with one specific medicine from their drug regimen. Among patients receiving three or more diabetes-related medicines, a majority of those who exhibited a degree of nonadherence did so, to a specific pharmacological agent [60]. Although the reasons for this non-adherence were not sought, it is highly likely that this behaviour may reflect intentional non-adherence in an effort to avoid adverse effects—intelligent non-adherence [84]. However, the role of poly-pharmacy and regimen complexity in determining intentional non-adherence amongst older adults has yet to be comprehensively evaluated.
6 Avenues for Improved Adherence The evidence for interventions improving intentional nonadherence is limited and the correlation between such interventions and improved clinical outcomes is inconsistent [85]; thus, amongst older adults it is highly challenging to describe avenues that may guide clinicians in this specific task. Moreover, many of the solutions proffered by researchers are not readily transferable into routine clinical practice, as they fail to appreciate the temporal and budgetary constraints that practitioners experience in everyday settings; this contrasts to interventions in the field of unintentional non-adherence, e.g. compliance aids and text messages, which are more practicable [86]. A variety of measures aimed at adherence in general (as opposed to intentional non-adherence amongst older adults) have been evaluated in the medical literature, including regular counselling from healthcare providers, simplification of drug regimens, changes in the communication style of healthcare providers and patient education (relating to adverse effect management). Meta-analyses, including a Cochrane review, suggest that no single approach consistently out-performs others in improving patient adherence [85, 87–89]—behavioural interventions produce a weighted effect size, r, of 0.17, whilst educational interventions produced a weighted effect size of 0.31; a combined educational, affective and behavioural approach generates an effect size of 0.34 [85]. Table 3 briefly summarises any interventions that address issues pertinent to intentional nonadherence amongst older adults—in effect, highlighting areas of potential future research, as a result of the paucity of current data in this specific population.
7 Conclusions Intentional non-adherence amongst older adults represents a significant issue, for patients, prescribers and policy
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makers. Leventhal’s Common-Sense Model of Self-Regulation [4] provides a theoretical construct through which such behaviour can be understood, highlighting particular factors that may motivate a patient to pursue such an approach in specific instances but not others. However, this article has demonstrated that our understanding and knowledge of such behaviour remains limited, particularly amongst older adults. More importantly, the ability to modify such behaviours through interventions with a sound evidence base requires urgent research. Acknowledgments and conflict of interest statements All authors were involved in the drafting and revision process. John Weinman is also Head of Health Psychology for Europe at Atlantis Healthcare. In this role, he has given talks, conducted research and overseen the development of patient support programmes for a number of pharmaceutical companies, including Abbot, Abbvie, AstraZeneca, Genzyme, Leo, Novartis, Roche, Servier and SOBI. These activities have in no way influenced the writing of this manuscript, which also poses no conflict of interest for Omar Mukhtar or Stephen H.D. Jackson.
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LEADING ARTICLE
Intentional Non-Adherence to Medications by Older Adults Omar Mukhtar • John Weinman Stephen H. D. Jackson
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Published online: 25 February 2014 Springer International Publishing Switzerland 2014
Abstract ‘The extent to which an individual’s medication-taking behaviour and/or execution of lifestyle changes, corresponds with agreed recommendations from a healthcare provider’, is a highly complex behaviour, defined as adherence. However, intentional non-adherence is regularly observed and results in negative outcomes for patients along with increased healthcare provision costs. Whilst this is a consistent issue amongst adults of all ages, the burden of chronic disease is greatest amongst older adults. As a result, the absolute prevalence of intentional non-adherence is increased in this population. This non-systematic review of intentional non-adherence to medication highlights the extent of the problem amongst older adults. It notes that age, per se, is not a contributory factor in intentionally non-
O. Mukhtar (&) Clinical Pharmacology and Therapeutics, King’s Health Partners, King’s College Hospital, Denmark Hill, London SE5 9RS, UK e-mail: [email protected] J. Weinman Institute of Psychiatry, King’s College London, London, UK S. H. D. Jackson Department of Clinical Gerontology, King’s Health Partners, London, UK
adherent behaviours. Moreover, it describes the difference in methodology required to identify such behaviours in contrast to reports of non-adherence in general: the use of focus groups, semi-structured, one-to-one interviews and questionnaires as opposed to pill counts, electronic medication monitors and analysis of prescription refill rates. Using Leventhal’s Common-Sense Model of Self-Regulation, it emphasizes six key factors that may contribute to intentional non-adherence amongst older adults: illness beliefs, the perceived risks (e.g. dependence, adverse effects), benefits and necessity of potential treatments, the patient–practitioner relationship, inter-current physical and mental illnesses, financial constraints and pharmaceutical/ pharmacological issues (poly-pharmacy/regimen complexity). It describes the current evidence for each of these aspects and notes the paucity of data validating Leventhal’s model in this regard. It also reports on interventions that may address these issues and explicitly acknowledges the lack of evidence-based interventions available to healthcare practitioners. As a result, it highlights five key areas that require urgent research amongst older adults: (1) the overlap between intentional and unintentional non-adherence, particularly amongst those who may be frail or isolated; (2) the potential correlation between symptomatic benefit and intentional vs. unintentional non-adherence to medication; (3) an evaluation of the source of prescribing (i.e. a long-standing provider vs. an acute episode of care) and the patient–prescriber relationship as determinants of intentional and unintentional non-adherence; (4) the decision-making processes leading to selective intentional nonadherence amongst older adults with multiple medical problems; and (5) the development and evaluation of interventions designed to reduce intentional non-adherence, specifically addressing each of the aspects listed above.
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Key Messages Intentional non-adherence represents a significant issue, particularly amongst older adults. Our understanding of the factors that lead to intentional non-adherence amongst older adults is limited and requires further research. Researchers must also develop and evaluate interventions that address these causative and contributory factors, relating them both to intentional adherence and to clinical outcomes.
1 Introduction The last 50 years has witnessed an unprecedented increase in the number of evidence-based healthcare interventions, e.g. lifestyle changes, pharmacological agents and operative/interventional procedures. As a result, professionals working in this field are often able to make recommendations to patients seeking medical advice, which may improve their symptoms and/or prognosis. However, the failure to follow such recommendations may jeopardise the patient’s health and well-being, frustrate the healthcare professional(s) involved and lead to a considerable waste of resources [1]. Although it may be unintentional, this is often not the case—a number of studies have shown that intentional non-adherence comprises approximately 50 % of all non-adherent behaviours observed amongst those over the age of 65 years [2]. Despite this and despite knowing that patients rarely volunteer such information, the issue of intentional non-adherence is all too frequently ignored by healthcare professionals—half of all general practitioners admit that they would like to confront their patients about the issue, but feel unable to do so [3]. This non-systematic review seeks to address this issue, with reference to older adults (aged over 65 years). It looks beyond the biomedical approach and adopts Leventhal’s Common-Sense Model of Self-Regulation [4] in an effort to describe the causes of intentional non-adherence and measures that may limit its occurrence. In doing so, it highlights important research questions, which have yet to be explored. In March 2011, a non-systematic literature search was conducted using PubMed (http://www.ncbi.nlm.nih.gov/ pubmed), MEDLINE and the Cochrane Database of Systematic Reviews; this was repeated in October 2013. The search prioritised studies published in the last 10 years and only included those available in the English language; however, older studies considered to be important by individual authors were also included, as was guidance
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from the National Institute for Health and Care Excellence. Further relevant references were selected from the bibliographies of identified papers. Key search terms (including combinations thereof and non-hyphenated versions) were: intentional, deliberate, non-adherence, non-compliance, non-concordance, elderly, older adults, geriatrics, medications, interventions and health psychology.
2 Compliance, Concordance, Adherence and Persistence Any review of intentional non-adherence would be incomplete without defining the terms compliance, adherence, concordance and persistence. Indeed, the term used to describe medication use as recommended by a doctor or other healthcare professional has been the subject of much discussion. Compliance is widely defined as ‘the extent to which a patient’s behaviour coincides with the prescriber’s recommendations’ [5]. However, the term has been criticised for its paternalistic implications, with the patient ‘‘passively following the prescriber’s orders’’ [5]. Furthermore, when discussing the issue of ‘non-compliance’, various groups have suggested that the term attributes blame to the patient [6, 7]. Adherence, ‘the extent to which a person’s medication-taking behaviour and/or execution of lifestyle changes, corresponds with agreed recommendations from a healthcare provider’ is considered by some to be more acceptable [8]. This is because it is thought to recognize the autonomy of the patient whilst emphasizing the patient’s agreement with the suggested recommendations [9]. Others have advocated the use of the term concordance, because of a belief that it reflects a more patient-centred approach—in this instance, healthcare professionals make a therapeutic alliance with the patient, in an effort to respect the patient’s wishes and beliefs about the treatment/intervention in question [9]. However, this descriptor provides no indication as to whether a treatment/intervention is followed. More recently, the term persistence has also been used in this field; this refers to the act of continuing a treatment for the prescribed duration and has been defined as ‘‘the duration of time from initiation to discontinuation of therapy’’ [10]. Those favouring this term highlight the fact that clinical outcomes are dependent upon both adherence and persistence; addressing both of these factors provides for a more complete understanding of medication-taking behaviour [10]. However, we believe that the principle of persistence is encompassed within the term adherence; the degree to which medication-taking behaviour and/or execution of lifestyle changes correspond with the agreed recommendations from a healthcare provider, implicitly includes a temporal aspect. Thus, the consensus of opinion
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amongst researchers, healthcare professionals and the World Health Organization favours the term adherence, which will be the preferential term for the purposes of this review [8, 11].
3 Intentional vs. Unintentional Non-Adherence? Historically viewed as a homogenous entity, non-adherent patient behaviours are increasingly divided into unintentional or intentional [12–15], with a small, but growing number of studies acknowledging that there may be an overlap between the two [16–18]. Unintentional non-adherence describes a situation where patients fail to follow a recommended therapeutic/healthcare-based intervention, without making a conscious decision [18, 19]. Thought of as a passive process on the part of a patient, it frequently encompasses inadvertent forgetfulness and an inability to follow treatment instructions because of a lack of understanding or physical problems, e.g. poor eyesight or impaired manual dexterity [18, 19]. In contrast, intentional non-adherence occurs when a patient consciously elects not to follow the measures recommended by a healthcare professional—it is best defined as an active decision on the part of patients to forego (discontinue, skip or alter) prescribed therapy [18, 19]. However, patients can, and do, exhibit both types of non-adherent behaviour, often at the same time—a finding observed amongst both older adults and their younger peers [15–17, 20]. Thus, whilst this non-systematic review highlights the issue of intentional non-adherence amongst older adults, it is important to acknowledge that a dichotomous approach (intentional vs. unintentional non-adherence) may not be all encompassing.
4 Intentional Non-Adherence in Older Adults: An Issue Worthy of Consideration? Our understanding of intentional non-adherence is further complicated by our inability to accurately record adherence using a widely accepted gold standard. The most commonly used techniques include a review of prescription records, self-reporting and pill-counts [21]. All three methods are problematic, particularly self-reporting, which is subject to recall bias and a reluctance on the part of patients to acknowledge non-adherence [21]. Medication measures, such as prescription ordering and prescription filling, represent an active first step toward taking a medication; however, they too are subject to error and manipulation as the possession of a medication does not equate to ‘… the extent to which a person’s medication-taking behaviour … corresponds with agreed recommendations
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from a health care provider’ [8, 22, 23]. Electronic monitoring of adherence-related events, e.g. the opening of a pill bottle or the depression of an inhaler, is prone to similar issues—despite being regarded by some as close to a goldstandard measure [24]. Although the above measures may delineate adherence from non-adherence, they offer little insight with regard to the specific issue of intentional non-adherence (Table 1). In an effort to explore this specific issue, researchers have thus far drawn upon a range of qualitative research techniques including questionnaires (e.g. the Beliefs about Medicines Questionnaire-Specific), focus groups and semistructured interviews [7, 25–29]. However, these methods are equally problematic, in that they are reliant upon candour from the respondent. Given such methodological issues, our need to understand non-adherence would be minimised were it not a sizeable problem with significant sequelae; however, the World Health Organization estimates that only 50 % of patients with a chronic disease will take their medication as agreed and the direct and indirect costs of non-adherence, in the US alone, are estimated at $US100 billion per year [8, 30]. With adults over the age of 65 years twice as likely to receive prescribed therapy compared with their younger counterparts [31], this issue is of greatest importance amongst older adults, in whom non-adherent behaviours have been associated with declining health, increased healthcare costs and increased hospital admissions [32–36]. In one study, 32 % of all medication-related attendances to the emergency department resulted from non-adherence [35]. Furthermore, the issue of intentional non-adherence is particularly worthy of consideration in older adults as a number of studies have indicated that between 33 and 75 % of all non-adherence in older adults is either exclusively or in part intentional [2, 37, 38]. Prior to further considering the issue of intentional nonadherence, it is important for readers to note that although advancing age may be associated with an accumulation of chronic disease for some, functional decline for others and increased rates of cognitive impairment, there are inconsistent data with regard to its role in non-adherence. A
Table 1 Methods evaluating intentional non-adherence Measures to evaluate intentional non-adherence Face-to-face, individual interviews Group interviews Focus groups Questionnaires, e.g. Beliefs About Medication Questionnaire, Reported Adherence to Medication Scale, Discrete choice experimentation Narrative exploration
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number of studies have suggested that older adults may demonstrate increased rates of adherence when compared with their younger counterparts [39–43]; others have demonstrated no effect or decreased adherence rates [44, 45]. Although such variations may be attributable to methodological differences, differences in the thresholds used to define older adults and geographical location, the inconsistent nature of the data challenges the populist view that older adults are more likely to exhibit non adherence, per se.
5 Explaining Intentional Non-Adherence: Insights from Health Psychology The traditional medical model provides one interpretation of intentional non-adherence amongst older adults [8]. However, health psychology offers an alternative, potentially comprehensive, patient-centred approach that is considered here. Early psychological attempts to explain non-adherent and adherent behaviours focused on selected personality traits [46]—whilst a number of descriptors were identified, e.g. conscientiousness (purposeful, well organised, selfdisciplined behaviours) this approach consistently failed to explain why individual patients demonstrate adherence to some medications and not others [46, 47]. As a result, health psychologists have drawn upon more sophisticated
models of human behaviour to explain and modify nonadherence. These include the Health Belief Model [48], the Theory of Planned Behaviour [49] and the Trans-Theoretical Model [50]. However, it is the Common-Sense Model of Self-Regulation (varyingly known as the Illness Perceptions Model, the Illness Representations Model, the Self-Regulatory Model and the Parallel Process Model) developed by Leventhal and colleagues [4], which unifies many of the themes engendered in these theories, from the perspective of a patient. The Common-Sense Model of Self-Regulation proposes that all threats to health (including illness) pose a challenge to an individual’s sense of self and their key goals; as a result, the individual actively attempts to make sense of these threats to minimise their impact [4]. This is achieved at both a cognitive and emotional level by developing representations (understanding), which duly generate behavioural responses (e.g. deciding to seek medical help, following medical advice). At the core of the individual’s representation (or understanding) of their problem are a number of related beliefs about the nature of the problem [4]. Thus, on experiencing a new symptom, the individual will typically label or describe that which they experience, linking it with other symptoms that they are experiencing/ have experienced in the past. These aspects constitute their perceived identity of the problem; this is typically linked with a causal explanation, as well as expectations about how long the problem will last (time-line), its likely effects
Table 2 Interventions addressing intentional non-adherence Factor
Intervention
Illness beliefs:
The published literature does not provide evidence of any specific interventions in older adults that have sought to modify illness beliefs in an effort to improve intentional non-adherence
Treatment beliefs:
There are no formal studies in the literature evaluating interventions in older adults that address the issue of treatment beliefs, where intentional non-adherence serves as the primary outcome measure A number of randomised controlled trials evaluating medicines reviews in older adults (aged [65 years) have demonstrated significantly increased adherence rates; however, the results are not entirely consistent, as other studies have reported no statistical difference [89]. Whilst the reviews varied widely in content and structure, knowledge of medicines was a feature of all interventions (see pp. 294–302 of NICE guidelines for more details) [89]
The patient–practitioner relationship:
No studies have sought to evaluate the effectiveness of an improved patient–practitioner relationship upon intentional non-adherence amongst older adults: the NICE guidelines on medicines adherence similarly report that no clinical tools have been evaluated that might aid a practitioner in establishing patient– practitioner congruence with regard to medicines [89]
Poly-pharmacy/regimen complexity
The published literature is notable for the absence of interventions in older adults that address the issue of poly-pharmacy and regimen complexity, with intentional non-adherence a documented outcome measure. A number of studies evaluating medicines reviews, sought to rationalize and simplify medicine regimens—the reported outcomes were mixed, with some studies demonstrating significantly increased adherence rates and others reporting no statistical difference. However, the focus remained on adherence in general, as opposed to intentional non-adherence [89]
The perception of self (intercurrent illnesses) Cost
There are no published interventions that have specifically sought to evaluate the treatment of inter-current illnesses in an effort to improve intentional non-adherence amongst older adults No specific interventions countering the effect of increased co-payments/cost have been evaluated in older adults, who exhibit intentional non-adherence
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(consequences) and the extent to which it is amenable to cure or control by the individual and others, e.g. healthcare professionals. Ultimately, these representations will influence how the individual responds to their initial symptoms, to the results of any subsequent investigation and to any recommended treatment or advice [4]. Using this model, it is possible to theorise that a number of factors may contribute to intentional non-adherence amongst older adults. These include illness beliefs and the perceived risks (e.g. dependence, adverse effects) and benefits of potential treatments—in turn, these may be influenced by external factors (e.g. interactions with healthcare professionals). Inter-current physical and mental illness may impact upon the perception of self and thus alter the degree of intentional non-adherence, whilst financial constraints and polypharmacy may also influence the goals of individual adults. 5.1 Illness Beliefs Using a cross-sectional survey, Rajpura et al. [51] demonstrated a significant and positive correlation (r = 0.332; p = 0.001) between medication adherence in general (measured using Morisky’s questionnaire) and illness perception scores (as assessed by a modified Brief Illness Perception Questionnaire) in older adults with hypertension. Similarly, Sofianou and colleagues [52] have demonstrated that self-reported non-adherence was more frequently observed amongst older adults with erroneous beliefs about asthma than those with appropriate illness perceptions. Although such studies demonstrate that illness beliefs influence overall adherence in older adults, the published literature is not explicit about the impact this factor has upon intentional non-adherence in older adults [51–54], thus warranting further investigation (Table 3). Nonetheless, such a relationship is intimated by the work of Lindquist et al. [12] who observed that older adults with adequate health literacy were significantly more likely to exhibit intentional non-adherent behaviours, when compared to those with inadequate and marginal health literacy. 5.2 Treatment Beliefs: Adverse Effects, Necessity and Efficacy Numerous studies have shown that perceptions relating to treatment play a critical role in influencing levels of nonadherence amongst patients of all ages [13, 29, 37, 55–62]. These can be broadly categorised into two; (1) the perceived necessity and efficacy of a treatment and (2) concerns relating to potential adverse effects, regardless of whether or not these can be scientifically validated [13, 29, 37, 55–62].
153 Table 3 Suggestions for future studies Further evaluation of the overlap between intentional and unintentional non-adherence, particularly amongst those who may be frail or isolated Detailed evaluation of the potential correlation between symptomatic benefit and intentional vs. unintentional nonadherence to medication Evaluation of the source of prescribing (i.e. a long-standing provider vs. an acute episode of care) and the patient–prescriber relationship as a determinant of intentional and unintentional non-adherence Evaluation of the decision-making processes leading to selective intentional non-adherence amongst older adults with multiple medical problems The development and evaluation of interventions designed to reduce intentional non-adherence amongst older adults
Looking specifically at older adults, Fried et al. performed interviews with 356 community-dwelling adults. Participants were asked about their willingness to take medication for the primary prevention of a myocardial infarction with varying degrees of benefit (absolute 5-year risk reduction) and harm (type and severity of adverse effects). Eighty-eight percent of those interviewed would take medication providing an absolute benefit of six fewer infarcts out of 100, approximating the average risk reduction of currently available medications. Eighty-two percent of participants who would take it remained willing to do so were the absolute benefit decreased by 50 %. In contrast, 69 % were unwilling or uncertain about taking such medication were it to cause mild adverse effects (e.g. fatigue, nausea); only 3 % would take medication with adverse effects severe enough to affect activities of daily living. Thus, the authors concluded that the willingness of older adults to take medication for primary cardiovascular prevention is relatively insensitive to its benefit but highly sensitive to adverse effects [29]. Using a study population primarily (78 %) over the age of 60 years, Ratcliffe and colleagues [59] demonstrated that patients are more likely to be concerned about the risk of relatively rare but serious adverse effects than relatively common, mild adverse effects. Similarly, Grant et al. [60] demonstrated that a population of older adults (mean age: 66 years) in receipt of multiple medications, were more likely to demonstrate nonadherence to those medicines not felt to be improving current or future health (6.1 vs. 6.9 days out of 7, p \ 0.001), when compared with those perceived to have long-term benefits. How such data relate to intentional non-adherence amongst older adults in everyday clinical practice is difficult to quantify, particularly in light of two important studies. Using a mixed study population of Japanese adults (age range 0–79 years; 64 % aged over 60 years) Iihara et al. [13] demonstrated that the perception of benefit was not associated with intentional non-adherence (although it was associated with unintentional adherence behaviours);
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the reliability of a translated European scale to assess beliefs about adverse effects and their impact upon intentional adherence was poor, thus negating this aspect of the study. In contrast, Schu¨z et al. [61, 62] demonstrated that increases in specific necessity beliefs predicted improved intentional adherence to medication using a study population consisting entirely of older adults (aged 65–85 years); the belief that a medication was harmful predicted a greater likelihood towards intentional non-adherence.
O. Mukhtar et al.
median age of 65 years) is associated with decreased adherence to statin therapy; Schu¨z et al. [62] observed that a greater number of illnesses was associated with increased concern about pharmacological treatment amongst adults aged 65–85 years. How such studies relate to intentional non-adherence is unclear. 5.5 Cost
As anticipated from the earlier, brief analysis of the Common-Sense Model of Self-Regulation, a number of factors external to the patient may have the potential to affect intentional non-adherence. One such factor is the patient–practitioner relationship, where a shared understanding (or representation) of the illness and treatment does not exist. A considerable body of research suggests that healthcare practitioners are directly able to influence the degree of non-adherence [28, 37, 63–68], with ‘personable’ prescribers likely to achieve greater rates of adherence compared with those deemed to be ‘business-like’ (61 vs. 35 %) [64]. Moreover, a congruence of vocabulary between patient and prescriber is known to correlate with the intention to adhere [65]. However, only a few of these studies focus on older adults [28, 55, 69] and none aim to correlate the patient–practitioner relationship with intentional adherence in older adults—thus identifying a further important gap in the published literature (Tables 2 and 3).
Much of the early research relating to the cost of medicines sought to correlate this variable with the use of medicines in older adults—in contrast to adherence and non-adherence, ‘use’ is an umbrella term that includes the prescription, supply and utilisation of medicines in a society [73]. However, there is now a growing body of evidence that suggests that economic considerations directly impact adherence amongst older adults [74–78]. Commercial insurers, in the US, reported a decrease in medication possession ratios (the percentage of time a patient has access to medication) as the copayment for ACE inhibitor use rose from $US5 to $US30 [76]; similarly, the Veterans Association found that the absolute difference in medication availability decreased by 7 % when co-payments were increased from $US2 to $US7, with an additional 12 % of patients experiencing undesirable treatment lapses of C3 months [77]. Moreover, a recent metaanalysis demonstrated an 11 % increase in the likelihood of non-adherence to medicines in publicly insured populations (mean age: 71.75 years) where co-payments are necessary; however, none of the studies included in the meta-analysis explicitly sought to determine whether cost/co-payment influences intentional or unintentional adherence [75].
5.4 The Perception of Self: Inter-Current Illness
5.6 Regimen Complexity and Polypharmacy
According to Leventhal’s model [4], those factors that alter an individual’s sense of self may also influence the degree of intentional non-adherence observed. Di Matteo et al. [70] reported that anxiety was not significantly associated with non-adherence; in contrast, depressed patients were three times more likely to exhibit non-adherent behaviours when compared with those who were not depressed (odds ratio: 3.03; 95 % confidence interval [CI]: 1.96–4.89). However, this meta-analysis, based on observational studies, did not focus on older adults or on intentional non-adherence and the subsequent literature has failed to address this specific question; thus highlighting a further focus for future studies (Table 3) [70]. Nonetheless, in 2013, Sundborn and Bingefors [71] demonstrated that symptoms of anxiety and/or depression were associated with both unintentional and, to a greater extent, intentional non-adherence—albeit in a mixed population, of which only 22 % of the 4,709 respondents were aged 65 years or over. More widely, Calip et al. [72] observed that breast cancer (in a population of women with a
A large meta-analysis by Claxon et al. demonstrated that increasing dose frequency correlated with declining adherence in patients, regardless of age [79]—in older adults (aged over 64 years), the use of at least one drug requiring multiple daily dosing is significantly associated with medication non-adherence (odds ratio: 2.99; 95 % CI: 1.24–7.17) [80]. Moreover, the conjunction of different medicines, such that they are taken collectively at one time point (polypharmacy) by older adults, may reduce adherence [47, 63, 81, 82]. However, such a correlation is not unequivocal—Corsonello et al. [80] were not able to demonstrate this relationship in older adults, whilst others have demonstrated that older adults prescribed greater numbers of tablets were more likely to demonstrate adherence [83]. Nonetheless, there is evidence that patients exhibit selective non-adherence when they are in receipt of multiple medications. A survey of 128 patients (mean age ± standard deviation: 66 ± 11.7 years) with diabetes
5.3 The Patient–Practitioner Relationship
Intentional Medication Non-Adherence in Older Adults
mellitus, undertaken in 2003, indicates that patients with suboptimal overall adherence tend to have problems with one specific medicine from their drug regimen. Among patients receiving three or more diabetes-related medicines, a majority of those who exhibited a degree of nonadherence did so, to a specific pharmacological agent [60]. Although the reasons for this non-adherence were not sought, it is highly likely that this behaviour may reflect intentional non-adherence in an effort to avoid adverse effects—intelligent non-adherence [84]. However, the role of poly-pharmacy and regimen complexity in determining intentional non-adherence amongst older adults has yet to be comprehensively evaluated.
6 Avenues for Improved Adherence The evidence for interventions improving intentional nonadherence is limited and the correlation between such interventions and improved clinical outcomes is inconsistent [85]; thus, amongst older adults it is highly challenging to describe avenues that may guide clinicians in this specific task. Moreover, many of the solutions proffered by researchers are not readily transferable into routine clinical practice, as they fail to appreciate the temporal and budgetary constraints that practitioners experience in everyday settings; this contrasts to interventions in the field of unintentional non-adherence, e.g. compliance aids and text messages, which are more practicable [86]. A variety of measures aimed at adherence in general (as opposed to intentional non-adherence amongst older adults) have been evaluated in the medical literature, including regular counselling from healthcare providers, simplification of drug regimens, changes in the communication style of healthcare providers and patient education (relating to adverse effect management). Meta-analyses, including a Cochrane review, suggest that no single approach consistently out-performs others in improving patient adherence [85, 87–89]—behavioural interventions produce a weighted effect size, r, of 0.17, whilst educational interventions produced a weighted effect size of 0.31; a combined educational, affective and behavioural approach generates an effect size of 0.34 [85]. Table 3 briefly summarises any interventions that address issues pertinent to intentional nonadherence amongst older adults—in effect, highlighting areas of potential future research, as a result of the paucity of current data in this specific population.
7 Conclusions Intentional non-adherence amongst older adults represents a significant issue, for patients, prescribers and policy
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makers. Leventhal’s Common-Sense Model of Self-Regulation [4] provides a theoretical construct through which such behaviour can be understood, highlighting particular factors that may motivate a patient to pursue such an approach in specific instances but not others. However, this article has demonstrated that our understanding and knowledge of such behaviour remains limited, particularly amongst older adults. More importantly, the ability to modify such behaviours through interventions with a sound evidence base requires urgent research. Acknowledgments and conflict of interest statements All authors were involved in the drafting and revision process. John Weinman is also Head of Health Psychology for Europe at Atlantis Healthcare. In this role, he has given talks, conducted research and overseen the development of patient support programmes for a number of pharmaceutical companies, including Abbot, Abbvie, AstraZeneca, Genzyme, Leo, Novartis, Roche, Servier and SOBI. These activities have in no way influenced the writing of this manuscript, which also poses no conflict of interest for Omar Mukhtar or Stephen H.D. Jackson.
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