Medication Non-adherence in Older Adults: Underlying Factors, Potential Interventions and Outcomes

Abstract

Polypharmacy is very common among older adults and is associated with poor health outcomes. This scoping review aimed to understand the underlying factors for poor medication taking by older patients and potential solutions to mitigate these risks. The ability to take medications and adherence are affected by various factors related to patients, treatments, health conditions and socio-demographics, healthcare providers and the healthcare systems. Educational and behavioural interventions are used alone or in combination for the optimisation medication use. Medication review and deprescribing, including regimen simplification, by trained practitioners has the potential to enhance patient safety and reduce healthcare costs. Engaging the patient and family may bring about additional benefits. Various technology-based interventions to promote self-efficacy are evolving and are used to support consumer self-management.

Key Points

Medication non-adherence in older adults is common and complex and is driven by memory deficits, polypharmacy, physical challenges, beliefs, social support gaps and system shortcomings.

Overcoming challenges to medication non-adherence requires a holistic, personalised approach combining regimen simplification, consumer education, use of technological solutions and supportive healthcare structures.

Multi-component interventions work best with older people, especially when tailored to the needs of individuals with cognitive or functional impairment.

Introduction

Older adults are a growing population in both developed and developing countries and are the largest users of prescribed medications [1]. They are also amongst the most susceptible groups for medication misadventure, with a high probability of adverse health outcomes, including hospitalisation [2]. Older people are prone to such complications due to the process of ageing, which is influenced by the body’s physiology [3]. Many people above the age of 65 years have multimorbidity and are often prescribed multiple medications [4]. Polypharmacy, commonly defined as the concomitant use of five or more medications [5], can occur at any age, although it is more common among older adults. Exposure to multiple medications by older people, especially ongoing use of medications no longer indicated (inappropriate polypharmacy) [6], may lead to poor health outcomes such as falls, drug interactions, non-adherence, hospitalisations and deaths [7]. Polypharmacy is also well recognised to be linked to higher hospital admission rates and healthcare system costs [8].

‘Potentially suboptimal medication regimens’ refers to a broad variety of signs, such as inappropriate polypharmacy, under-prescribing and high-risk prescription, which involves prescribing potentially inappropriate medications, which may raise the risk of medication-related harm. The burden of disease and medication consumption are predicted to be on the rise in the context of an ageing population. Therefore, minimising preventable medication-related harm and ensuring the safety of medications are important public health challenges that call for further studies [10].

Medication taking is a complex human behaviour, and patients evaluate medications, and their associated risks and benefits, with the help of available resources. Thus, the thoughts and actions of an individual are mostly rational. The Health Belief Model (HBM) suggests that a behaviour will be carried out if the ‘perceived threat’ (based on severity and susceptibility of the condition) is high and the ‘perceived benefits’ (of the behaviour) outweigh barriers. The newer version of the HBM also focuses on the ‘self-efficacy’ [11, 12]. It refers to an individual’s belief in their capacity to perform a specific behaviour or task effectively. It is also related to the likelihood of a person engaging in a desired behaviour. Thus, a patient using chronic medications who adheres to their healthcare provider’s medication regimen demonstrates self-efficacy.

Unwanted and unused medications often result from inadequate communication between health professionals and patients about health problems and how they might be treated, and about patients’ ongoing assessment and experience of treatments [13]. They represent a loss not just for patients but also for the healthcare system and society; they also continue to be a major source of frustration for health professionals and impede the achievement of therapeutic goals. The traditional medical model, which historically has focused on managing a specific disease condition, as opposed to managing the patient’s case more holistically, has proven to be both expensive and ineffective in the treatment of chronic diseases [14].

The current review aimed to identify the underlying factors for non-adherence in older patients, potential interventions to address non-adherence and outcomes. Accordingly, a set of keywords was identified that included ‘medication non-adherence’, ‘medication non-compliance’, ‘medication persistence’, ‘aged’, ‘ageing’, ‘older adults’ and ‘elderly’. The terms were combined using appropriate Boolean operators to develop the search string. The search string was used to identify relevant articles through electronic searches of Medline and by the hand searching method. The search was restricted to articles from January 2001 to February 2025 focusing on newer interventions developed for improving adherence.

Medication Non-adherence

Medication non-adherence is a complex and dynamic behavioural process that is strongly influenced by factors at intrapersonal, interpersonal, service and system levels [15]. Forgetfulness due to interruptions or changes in routines [16], refusal to take medication due to concerns about side effects, lack of stock of medications, physical difficulty or inconvenience of using medications, lack of sufficient time [17], social stigma, perceived lack of need for the medication and/or lack of effects or benefits [18] and lack of symptoms [19] were some of the reasons cited by patients for treatment non-adherence. This is not an exhaustive list; in many studies, these were options offered to patients through structured questionnaires and may not have covered all the factors affecting non-adherence.

A systems model for adherence by the World Health Organization (WHO) classifies the factors influencing adherence into five major domains, related to patient, social and economic factors, health conditions, treatments and healthcare team and system-related factors. Patients’ function, knowledge, attitudes and views and beliefs are all considered patient-related aspects [20]. Medication adherence is impacted by a patient’s knowledge of illnesses and treatments, beliefs and attitudes about medication use and the efficiency of symptom control, according to both quantitative and qualitative research [21]. Social and economic aspects encompass a range of characteristics associated with patients, including demographics, socio-economic factors, literacy, social support systems, housing circumstances and drug cost, in addition to some environmental and cultural elements. Medication non-adherence has been linked to several socio-economic characteristics such as age, gender, ethnicity, educational qualifications, employment and financial status [22]. Health-related factors representing the health or disease-specific concerns may include comorbidities, extent of disability, severity of symptoms, depression or psychological disorders [23].

Factors Predicting Non-adherence

Studies published on medication taking have shown several predictors of non-adherence in older adults. Prescription of complex medication regimens and multiple dosage forms are common in older patients, potentially jeopardising their adherence [24]. The same patient may demonstrate different adherence patterns on various occasions, based on disease severity, presence of comorbidities, complexity of medication regimen, types of medications and reinforcement and nature of follow-up from health professionals [25]. Some of the predictors of non-adherence among older adults are discussed in Table 1.

Table 1.

Factors affecting adherence along with the direction of relationships

Category	Disease/context	Factors	Direction of relationship (as per the studies)	References
Socio-demographic factors	Older adults with cancer	Home and family life	Negative	[26]
	Asthma, COPD	Cognitive performance/secondary memory	Negative	[55]
	Older adults	Age	Negative	[54]
	Cognition	Medication literacy	Positive Negative	[59] [60]
	Cancer, COPD	Knowledge and confidence	Positive Negative Mixed	[14, 18, 28, 61–65] [30] [19, 49]
Disease- and therapy-related factors	Depression	Disease severity and symptomatology	Positive Negative Neutral	[27] [16] [28]
	COPD	Disease burden	Positive Negative	[28] [28, 35–37]
	COPD	Regimen complexity	Positive Negative Neutral	[47] [48, 49] [37, 46]
	Hypertension	Perceived efficacy of treatment and symptom relief	Positive Negative Mixed	[27, 47] [18, 50, 51] [17, 52]
Psychosocial factors	Older adults	Health behaviours	Positive	[73–75]
Professional factors	Older adults	Experience and skill sets	Positive Negative	[53] [51, 66, 67]
Climatic factors	Chronic conditions	Time	Positive Negative Neutral	[27] [14, 17, 64] [16]
	Patient beliefs	Seasons	Neutral	[18]

COPD chronic obstructive pulmonary disease

Socio-demographic Factors

Little conclusive evidence is available on the impact of socio-demographic factors such as age, gender, marital status, education, income and race on medication adherence [26]. Socio-demographic features are less likely to have direct influence on patient adherence. Nevertheless, they may affect patients’ adherent behaviours by altering cognition and/or attitude to both illness and management.

Medication Literacy

Medication literacy is defined as “the degree to which individuals can obtain, comprehend, communicate, calculate and process patient-specific information about their medications to make informed medication and health decisions in order to safely and effectively use their medications, regardless of the mode by which the content is delivered (e.g. written, oral and visual)” [27]. It may be important for the evaluation of the rational use of medicine. Some studies have shown that most of the medication-related adverse events may be prevented by increasing awareness. However, the relationship between medication knowledge and medication adherence has not been clearly explained [28]. A cross-sectional survey conducted among patients with coronary heart disease in China showed that there was a significant correlation between medication literacy and non-adherence in patients admitted to hospital [29]. Similarly, Muellers et al. [30] identified that low health literacy among patients with moderate to severe COPD is associated with decreased medication adherence. However, in this study, support from caregivers was not associated with a better medication adherence among patients with low health literacy [30].

Knowledge and Confidence

Confidence in drug therapy was found to be a significant factor contributing to adherence [13]. Patients’ knowledge of the purpose of the treatment and the consequences of omission, but not knowledge of the risk of toxic effects, was correlated to adherence to prescribed drugs in terms of their number, daily dose and frequency [31]. Patients known to have access to a self-management plan have reported better self-care ability [32]; however, higher perceived knowledge was not associated with better self-management knowledge scores. Follow-up education and feedback on usage have been shown to improve adherence to prescribed medications; instruction has shown a mixed impact on the inhalation technique in patients [33]. Awareness of the function of the electronic monitoring device reduced the incidence of medication dumping among patients participating in a clinical trial of an inhaled bronchodilator. Patient knowledge about the role of treatment, confidence and feedback from health professionals is likely to enhance treatment adherence [34].

Disease- and Therapy-Related Factors

Disease Severity and Symptomatology

The severity of symptoms may be associated with adherence [14]. Disease severity should be assessed frequently when poor adherence is reported [35]. Adherence to domiciliary nebulised therapy measured using electronic monitors in a group of patients with COPD with severe disease was no different from that of other patient groups [36]. Poor adherence to inhaled steroid medications was observed even among patients with COPD who had hospitalisations, emergency department admissions, night awakenings and high prednisone requirements [37]. These findings suggest that disease severity is not an independent predictor of adherence. Clinically significant symptoms of depression and high morbidity are known to be associated with lower adherence to medications among older adults. These data manifest the role of depression as an important risk factor for disease progression and a target for interventions focusing on improving self-management in the older population. Future research should focus on identifying the self-management domains that are mostly affected by depression, and also whether interventions targeting depression improve adherence and disease outcomes in this population. Pathways linking depression with low medication adherence may be an effective target for improving outcomes in the older population [38].

Disease Burden

Ambulatory patients using a health maintenance organization (HMO) had an average of 3.7 chronic medical conditions compared with 1.8 for control subjects. Adherence in patients with common comorbidities such as cardiovascular diseases and arthritis is known to be better than that in pulmonary diseases [39]; however, depression, a common comorbidity in older patients with chronic conditions, is a known risk factor for non-adherence [40]. Greater impairment in quality of life was found to be associated with poor adherence to treatment [41]. It is likely that older people with multiple comorbidities become more health conscious due to their increasing disease burden, resulting in improved adherence, but the need for managing a more complex medication regimen could be an issue in patients with cognitive impairment and those with depressive illness, which might explain the poor adherence observed in many older adults.

Regimen Complexity

Among patients attending a chest clinic and two allergy/asthma clinics in the UK, medication adherence in those taking three or more drugs was not significantly different from those taking two drugs or fewer [42]. Dosing frequency did not have any major impact on adherence (measured electronically) to home nebulised therapy among patients with chronic respiratory disease recruited from the database of a hospital in London [43]. Adherence in 119 patients from a HMO in the USA, assessed based on pharmacy claims data, found no significant differences relative to prescribed dosing frequency (twice daily or less compared with three times daily or more) [39]. Prescription of multiple inhalation devices that need to be handled differently was found to confuse patients with chronic respiratory disease attending the pulmonary outpatient clinics of a Dutch hospital and to result in incompetent inhalation techniques [44]. These findings suggest that regimen complexity is not an independent predictor of non-adherence, especially intentional non-adherence; however, complex regimen features might result in unintentional non-adherence.

Perceived Efficacy of Treatment and Symptom Relief

Finding the therapy ineffective was the reason by one third of patients who reduced the time of receiving supplemental oxygen, according to a French study that assessed the daily use of oxygen therapy in patients with COPD [45]. Lack of belief in the routine benefit derived from treatment may have influenced many ambulatory patients with COPD to discontinue medications, despite continuing to renew their prescription [46]. In a clinical trial of an education program in Norway, steroid inhaler adherence assessed using dispensing data improvement was noticed among asthmatics, but not patients with COPD. However, the use of rescue medication (inhaled bronchodilators) among patients with COPD in the intervention group was more than half the amount in the control group [47].

Psychosocial Factors

Variables such as beliefs, expectations, anxiety, behaviour and health are separate facets of individuals according to health psychology. It assesses the inter dependency of these variable and the complexity among them (e.g. beliefs create changes in behaviour, behaviours cause changes in health, emotions cause changes in behaviours) [48]. Mortality and longevity of individuals are influenced by health behaviours; hence health psychologists have attempted to identify and assess health-related behaviours. Sociological research is based primarily on qualitative methods and examines people’s perception about the disease and treatment, whereas psychological research has been focusing on the development of models to elaborate various ways where beliefs can determine the behaviour. Theoretical clinical methods usually employ multiple regression analysis to identify predictors of outcomes from amongst demographic and clinical variables. Several correlational studies have attempted to predict health behaviours, but only few studies have been conducted in patients with COPD [49].

Aids for adherence or compliance can extend from strategies, tools or interventions that can help the patients hold to the therapy strategies prescribed by the healthcare professionals. Research on the area has dug out enormous opportunities for medical aid-related innovations. Patient education and counselling, reminders sent in mobiles, medication packaging strategies, incentives and rewards for adherence are the common practices to ensure the compliance and adherence of the patients. Older adults should be well-occupied with the strategies to comply with the therapies instructed.

Professional Factors

Patients who had been prescribed an MDI at a hospital were found to have better inhalation techniques than those who were initiated on an MDI by their general practitioner [50]. When healthcare professionals are unsure and have questionable inhalation skills, their patients cannot be expected to use the inhalation devices properly. The importance of effective patient–clinician interaction for patients’ optimal adherence to therapeutic regimens though well recognised [51–53].

Time and Seasonal Factors

Older adults (above 65 years of age) are sensitive to climatic changes when exposed to climate stressors and have less adaptability, potentially resulting in harm [54]. Despite periodic reinforcements, adherence to recommended management in several clinical trials in patients with COPD kept declining and never returned to the initial level [55, 56]. No statistically significant differences between morning and evening adherence to inhaled steroid medications were observed in patients with chronic respiratory disease. In a progressive disease such as COPD, adherence might improve over long periods of time due to worsening of disease symptoms; however, in the short-term, adherence is likely to decline over time, unless enhanced by feedback and reinforcement [57].

Potential Interventions for Improving Medication Adherence

A Cochrane systematic review identified a range of simple to complex interventions for improving medication‐taking ability and medication adherence in older adults prescribed multiple medications. These interventions were delivered by a variety of healthcare professionals, including physicians, pharmacists, nurses and others. Interventions were categorised into three broad groups: educational interventions, behavioural interventions and mixed interventions (i.e. both educational and behavioural) [58].

Educational Interventions

Educational interventions comprise medication/health education (provided in writing and/or verbally) delivered to the patient or carer and/or review of patient medications.

Behavioural Interventions

Behavioural interventions include motivational interviewing, self-administration training [59] including routinisation, use of pill reminder devices, dose administration aids, automated dosing devices, text message adherence reminders and digital/electronic remote monitors.

Education and Coaching

Education can improve health literacy, which is directly proportionate to optimal disease management, which includes medication adherence [60]. Educational interventions delivered at patient homes showed better medication adherence than in the clinics. Significant improvement in medication adherence was noticed after two to three sessions, but the differences between groups were not found after three sessions.

Medication Review: Deprescribing and Regimen Simplification

Medication therapy may improve health-related outcomes by slowing down or halting disease progression and by easing symptoms of disease. Thus, medication management is the cornerstone of care in older adults [61].

‘Medication review’ refers to a systematic assessment of a patient’s medication management with the aim of optimising the quality use of medicines and minimising medication-related problems (MRPs) [62]. The three types of medication review are:

1. Prescription review for clarity, validity and appropriateness.

2. Medication adherence review to address issues relating to the patient’s medicine-taking behaviour.

3. Clinical medication review to address issues relating to the patient’s use of medicines in the context of their health condition(s) and aimed at reaching an agreement on the right choice of medications, optimising their effects and minimising MRPs.

Medication review is a multidisciplinary responsibility that ensures the ongoing safe and effective use of medicines at all stages of the medication management pathway. A clinician (doctor, pharmacist, nurse practitioner or nurse) may conduct or supervise the various types of medication reviews depending on their scope of practice, practice area, clinical experience, ability to effectively communicate and training/accreditation [62, 63].

Medication Adherence Review

This involves partnering with the patient to gain an understanding of how they actually take their medications and what their beliefs about medications are. Reviewing past prescription records and refill data may provide valuable insights into the patient’s medicine use. Open discussion with the patient, being non-judgemental and respecting the patient’s beliefs about medications and their prescribers are paramount.

The key elements of a medication adherence review include:

1. Assessing the actual pattern of medication usage (frequency, regular/as-needed use, use of non-oral dosage forms, use of new medications, dose changes, difficulties experienced in using medications and review of past medication use)

2. Assessing beliefs about medications (the purpose of each medication, perceived benefits and perceived harms) [64]

3. By exploring these factors, ascertaining the presence of unintentional and/or intentional non-adherence and potential barriers to adherence

Deprescribing has been defined as “the process of withdrawal of an inappropriate medication, supervised by a health care professional with the goal of managing polypharmacy and improving outcomes” [65]. Deprescribing interventions directly aim to withdraw specific medications, while medication optimisation includes contrasting elements such as starting a previously omitted medication. Implementation of deprescribing strategies, including regimen simplification, with the involvement of adequately trained clinical pharmacologists or hospital pharmacists have the potential to enhance patient safety and reduce healthcare costs by minimising the prescriptions of potentially inappropriate medications [66].

A systematic review and meta-analysis comprising both interventional and observational studies evaluated the effect of various medication review and deprescribing interventions in hospitalised older patients. The results showed a slight but statistically significant 8% reduction in hospital readmissions [hazard ratio (HR): 0.92; 95% confidence interval (CI): 0.85–0.99] following medication review and deprescribing, but no significant impact on mortality (HR: 0.98; 95% CI 0.96–1.00) [66].

A systematic review which included 24 RCTs (participants: 13,007) investigating the effect of deprescribing on health outcomes (mortality, adverse drug withdrawal, physical health, cognitive function, quality of life and medication regimens) comprised 12 studies in the community, 5 studies in hospitals and 7 studies in residential aged care facilities [67]. Subgroup analyses of randomised studies on deprescribing polypharmacy demonstrated a significant reduction in mortality in young older patients (aged 65–79 years) [odds ratio (OR): 0.71; 95% CI 0.51–0.99) and when patient-specific interventions were applied (OR: 0.79; 95% CI 0.63–0.99). However, a generalised intervention consisting of practitioner education or computerised decision support systems did not change mortality (OR: 1.04; 95% CI 0.81–1.33; participants: 8482; studies: 5). Active engagement of the patient and/or caregiver may further increase the effectiveness of such interventions by enhancing adherence [68]. The benefits of deprescribing may be greater in people under 80 years of age, as the long-term negative effects of inappropriate polypharmacy may be irreversible after a certain point. Additionally, a patient-specific approach to deprescribing may be more likely to improve longevity due to increased patient engagement and empowerment. Another meta-analysis and systematic review of randomised controlled trials (RCTs) of the effect of deprescribing interventions on clinical outcomes in older adults found that in four RCTs with 1144 patients, the experimental group demonstrated a statistically significant improvement in medication compliance compared with the control group after the intervention [relative risk (RR) 1.26; 95% CI 1.02, 1.55; P = 0.03] [69]. Polypharmacy stewardship is a novel concept aimed at promoting the appropriate use of medication and minimising medication-related harm, taking into account potentially inappropriate medications, potential prescribing omissions, drug–drug and drug–disease interactions and prescribing cascades [9].

Nursing care for older people may involve their family through training, by giving a positive feeling to family members who take care of them, and through counselling to ensure that the patient uses the right medication and follows correct methods of storage and disposal [70].

Behavioural Interventions

Motivational interviewing (MI) is defined as “a collaborative conversation style for strengthening a person’s own motivation and commitment to change” [71]. MI facilitates behaviour change through:

• (i)Engaging, which establishes a cooperative relationship between the counsellor and client.
• (ii)Focusing, which helps identify and define goals with the client for guiding the next processes.
• (iii)Evoking, which assists clients in examining their motives and resolve any ambivalence towards change.
• (iv)Planning, which involves creating a detailed action plan once the client commits to change.

A meta-analysis evaluating the role of MI in patients with hypertension found that MI could reduce both systolic pressure and diastolic blood pressure levels in patients with hypertension, while simultaneously enhancing their self-efficacy, quality of life and medication adherence [72].

Consistency in medication-taking routines were more likely to be associated with good adherence to medications over time and have better systolic blood pressure control [73]. Health coaches are being utilised to help patients improve their management of chronic conditions and to deliver important resources for the improvement of medication adherence, in turn reducing medication errors.

Technological Advancements in Medication Adherence/Compliance

A network meta-analysis of many different interventions showed that those with a technology-based approach had a positive, but short-lived, effect on medication adherence [74]. The mean age of participants varied depending on the disease and ranged from 46.5 (SD 9.9) to 73.8 (SD 7.5) years. Medication counselling provided by trained medical assistant health coaches improved medication concordance and increased adherence [75].

A systematic review and meta-analysis of mobile app interventions targeting medication adherence in patients with chronic diseases showed a positive impact of mobile apps on improving medication adherence. The subgroup analysis results revealed greater effectiveness of interventions using interactive strategies, advanced reminders, data-sharing and pill dispensers [76]. Use of mobile phone facilitates the monitoring of the treatment process and healthcare provider–client relationship. However, many apps that are designed for the general population may not be user-friendly for older people. A medication management app customised for the special conditions of older adults has been shown to improve medication adherence and reduce adverse events [77]. Any adherence aid should be chosen in consultation with the patient and should match the patient’s abilities, as different aids require varying manipulative skills.

Digital personal assistants are among the latest trends for ensuring medication adherence in older adults. Balasubramanian et al. utilised a digital personal assistant ‘smart speaker’, Alexa Echo Show 8, for remote assistance of patients during coronavirus disease 2019 (COVID-19). These patients were under ongoing therapy sessions for chronic conditions [70]. The indicators serve as an alternative to the inappropriate disease-focused quality metrics and can help in promoting patient-centred care in the target group. They will help identify the approaches for quality improvement and advance standardisation for patient care delivery. Their implementation should be continuously monitored for promoting their dynamic maintenance and the adaptation of the indicators [78]. Digital health systems also provide adequate self-management support for people with chronic conditions [79]. Even though many digital health systems are available for healthcare, the feasibility remains a concern. However, low computer and online literacy for some of this population presented implementation challenges that should be considered in digital health adaptations [80].

Conclusions

Medication adherence continues to be a major challenge among older adults. Adherence to therapy is a multifactorial concern among older adults and can be understood only in the context of the individual’s socio-economic, psychological and physical conditions. Knowledge on the factors influencing non-adherence based on the patient’s perspective is essential in developing tailored interventions. Various educational and behavioural strategies can be applied individually or in combination for improving adherence. Educational and motivational strategies are likely to help in addressing the intentional non-adherence, whereas behavioural and provider-focused strategies are more likely to be successful in addressing unintentional non-adherence. Mobile health and home monitoring devices with real-time monitoring of symptoms and data through Bluetooth-enabled gadgets and feedback on disease management, including treatment adherence, are also becoming widely available for better patient care. Doctors, pharmacists, nurses and patients play an important role for optimising adherence, in turn leading to better health outcomes.

Funding

Open Access funding enabled and organized by CAUL and its Member Institutions. This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Declarations

Conflict of interest

The authors have no relevant financial or non-financial interests to disclose.

Data availability

Data sharing is not applicable to this article, as no new data were created or analysed in this study.

Ethics statement

Not applicable.

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Consent to participate

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Code availability

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Author contributions

E.A.R.S. and R.V. contributed equally to the writing of the original draft, and J.G. was responsible for reviewing and editing the manuscript.