Intentional non-adherence to medications by older adults.

'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-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 non-adherence 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.