Effectiveness of Interventions to Improve Health Literacy on Medication Use Among Older Adults: A Systematic Review

Abstract

Background/Objectives: Older adults should be capable of reasoned judgments regarding their health, lifestyle, and disease management. Therefore, interventions to improve Health Literacy (HL) are essential for empowering older adults to make choices that improve their quality of life. Correct medication use is vital to maintaining and enhancing health outcomes in older adults. This study aimed to identify the most effective HL interventions with impact on medication use among older adults. Methods: A systematic review was conducted using MEDLINE (PubMed) and EMBASE to identify interventional studies evaluating HL interventions that have an impact on medication use in older adults. Results: Three studies satisfied the inclusion criteria. The evidence indicates that HL interventions have positive effects and can be effectively implemented by several healthcare professionals through tailored communication strategies. However, the review underscores a substantial lack of high-quality research on HL strategies aimed at improving medication use in older adults, particularly given the increasing prevalence of chronic diseases and polypharmacy in this population. Conclusions: This systematic review identifies substantial research gaps regarding HL interventions and their impact on medication use among older adults. While the included studies demonstrate encouraging outcomes, further rigorous research is necessary to develop specific HL interventions addressing medication-related challenges in older adults.

1. Introduction

The understanding of Health Literacy (HL) has evolved from a focus on cognitive abilities to a broader perspective that also considers personal and social skills [1]. HL empowers individuals to access, comprehend, and utilize health-related information in ways that support the preservation or promotion of well-being. It encompasses several competencies, including interpreting prescription drug labels, understanding health information, and communicating effectively with healthcare professionals [2,3].

Higher levels of HL are correlated with better health status, better healthcare for chronic disease conditions, and higher use of preventive care [4]. In contrast, low HL can lead to confusion around medication use and poor overall health outcomes [1]. Older adults appear to be at the greatest risk, as they generally exhibit lower HL levels and higher healthcare utilization [5,6,7]. Clinical research consistently shows that older adults have lower HL levels compared to younger adults, with 35–56% of older adults demonstrating inadequate HL. This is associated with difficulties understanding medication instructions, greater risk of non-adherence, and increased healthcare utilization [1,8,9].

As people age, they become more susceptible to chronic diseases and often require multiple medications. Older adults are particularly vulnerable to chronic diseases such as coronary heart disease, diabetes, and hypertension, which can lead to multimorbidity and polypharmacy [10]. Therefore, compliance with treatment is essential to minimize adverse events and ensure safe and effective care [7]. This need is reinforced by predictive data from the World Health Organization, which estimates that cardiovascular disease rates among older adults will double by 2050 due to demographic aging and accumulating risk factors [11].

Older adults face unique challenges related to HL that distinguish them from other age groups. Cognitive decline, sensory impairments (such as vision and hearing loss), and decreased processing speed can adversely affect their ability to access, understand, and use health information effectively. Moreover, this population commonly experiences multimorbidity and polypharmacy, which increases the complexity of medication regimens and the need for accurate health comprehension to ensure safe medication use [12]. Several studies show a higher number of older adults who struggle with limited HL, which can make it hard for them to manage their medication properly [3,5]. This can lead to issues like not taking their medication as prescribed or facing negative side effects. Many of these older adults also deal with money problems, have a poor view of their health, and aren’t happy with their primary healthcare services [9]. This can contribute to confusion about medication, resulting in errors, misinterpretation of medication instructions, and a lack of awareness regarding potential drug interactions and side effects [1].

Additionally, older adults often have lower rates of digital literacy and limited access or familiarity with internet and mobile health technologies, which further complicates their ability to obtain and use health information in modern healthcare environments [13,14].

Improving HL is a key strategy in addressing medication non-adherence [3]. To mitigate this challenge, particularly among older adults who face difficulties in accessing health information and managing their care, professionals have introduced educational sessions and implemented tools such as digital pillboxes and mobile health applications. These resources are designed to enhance adherence and support healthier behaviors [15].

However, medication adherence and safe use continue to present significant challenges. Evidence shows that educational interventions, particularly those that are frequent, verbal, and interactive, can significantly improve drug literacy and adherence while reducing administration errors, complications, and hospital readmissions [16,17]. Interventions that include personalized education, pharmacist-led counseling, and technology-assisted tools have positively affected medication use [18]. Tailoring these efforts to each individual, making them culturally relevant, and reinforcing the information enhance understanding and adherence, which helps prevent errors [18]. Although these interventions may not directly influence long-term outcomes such as disease recurrence or mortality, multi-faceted and culturally sensitive intervention approaches are the most effective, especially in socioeconomically disadvantaged communities. These highlight the importance of integrating comprehensive HL strategies into educating older adults to promote better health outcomes and empower them to manage their care effectively [19].

Healthcare professionals can improve medication use among this population by enhancing HL, providing accessible information, simplifying instructions, and creating supportive environments that empower informed decision-making [20]. However, there is a lack of studies systematising evidence on the impact of HL interventions on appropriate medication use and which interventions are more effective. This systematic review aimed to find out which HL interventions improve medication use among older adults.

2. Materials and Methods

The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [21] (Supplementary Table S1).

2.1. Search Strategy

A literature search was conducted in April 2025 on MEDLINE/PubMed and EMBASE electronic databases. The search strategy aimed to identify relevant studies on interventions designed to improve HL and their impact on medication use among older adults. The search utilized the following broad terms: “(health literacy) AND (older OR vulnerable OR elder * OR geriatric) AND (intervention OR trial) AND (medication adherence OR drug therapy adherence OR medication manag * OR compliance)” (Supplementary Table S2).

2.2. Selection Criteria

The inclusion criteria were studies focused on interventions aimed at improving HL and that analyzed the impact on medication use among older adults (≥65 years of age); Eligible study designs included interventional studies (Randomized controlled trials, Nonrandomized controlled clinical trials, before–after (pre–post) studies). Only studies published in Portuguese, English, or Spanish between 1 January 2013 and 31 March 2025 were considered.

2.3. Outcome Measures

The primary outcome was the effectiveness of HL interventions on medicine use, assessed by analyzing changes in HL levels, medication adherence, or older adults’ medication knowledge, before and after the intervention.

2.4. Data Extraction

Study selection was carried out in two stages with the Rayyan tool [22]. In the first stage, two researchers (CP and AIP) independently performed an initial screening based on titles and abstracts of all articles retrieved from the databases. Both researchers assessed whether the articles met the inclusion criteria. In case of disagreement, a third researcher (FR) reviewed the article and made the final decision. In the second stage, two researchers (CP and AIP) independently screened the full text. All discrepancies were resolved through discussion with the help of a third researcher (FR).

2.5. Quality Assessment

The quality of the included studies was assessed using tools provided by the National Institute of Health (NIH), in particular the “Quality Assessment of Controlled Intervention Studies” and “Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group” tools, depending on the study design [23]. The JBI Critical Appraisal Checklist for Quasi-Experimental Studies was also applied where appropriate [24]. For each study, the risk of bias and quality were assessed independently by two researchers (CP and AIP). In case of disagreement, a third reviewer acted as a referee to reach a consensus (FR).

2.6. Data Synthesis and Presentation

Two researchers (CP and AIP) independently extracted data from the included studies using a standardized Excel form. The extracted data included the authors, year of publication, country, study design, sample size and follow-up period, study population, intervention applied, strategic objective, operational details of the intervention, comparators, outcome measures, and main results.

3. Results

3.1. Study Selection

A total of 1020 studies were identified through the database search and screened by title and abstract (Figure 1). Of these, 25 articles were selected for full-text review. After assessing the full texts, 22 studies were excluded for not meeting the inclusion criteria. Supplementary Table S3 summarizes the reason for excluding each study that progressed to full-test screening (n = 22).

Three studies fulfilled the inclusion criteria and were included in this systematic review [17,18,19].

3.2. Characteristics of Included Studies

A description of the characteristics of the included studies is presented in

Table 1. Characteristics of the included studies (n = 3).

Author, Year	Country	Study Design	Setting	Specific Disease	Older Patients Sample		Comparator	Quality Assessment *
					Sample Size	Age
Chen et al., 2022 [10]	China	RCT	Post-discharge	Coronary heart disease	116 (C:58 I:58)	≥65 years old	Patients with routine drug education	12/14 a
Ng et al., 2017 [25]	China	Non-RCT	community	-	50 (C:25 I:25)	≥65 years old	Without intervention/usual care	5/9 b
Grice et al., 2014 [26]	USA	Pre–Post Intervention Study	independent-living senior facilities	-	2009–2010-159; 2010–2011-147; 2011–2012-153	seniors	Without comparator	4/12 c

* Score obtained/total score, ^a The National Institutes of Health (NIH) quality assessment tool of controlled intervention studies, ^b JBI Critical Appraisal Checklist for Quasi-Experimental Studies, ^c The National Institutes of Health (NIH) quality assessment toll for Before–After (Pre–Post) Studies with No Control Group.

. Of the three included studies, two were conducted in China [10,25] and one in the USA [26]. The study designs varied: one was a Randomized Controlled Trial (RCT) [10], one was a non-RCT [25], and the third was a Pre–Post Intervention Study [26]. The study included post-discharge context [10], a community setting [25], and a facility for independent-living older adults [26]. Only one study specifically targeted older adults with a specific disease, coronary heart disease. The sample sizes ranged from 50 to 159 older adults.

3.3. Quality Assessment of Included Studies

The quality of the three studies is shown in Supplementary Table S4. Only one study fulfilled more than 80% of the exploratory questions [10], while two studies revealed potential sources of bias [25,26]. The main limitations identified across these studies included the lack of randomization [10], the authors did not report whether the sample size was sufficiently large to ensure adequate statistical power [26], the outcomes weren’t measured reliably [25], the sample size wasn’t large enough to provide confidence in the findings on the outcomes reported [26], or subgroups analyzed weren’t prespecified [26]. There weren’t multiple measurements of the outcome [26], sometimes the follow-ups were not complete [25], the selection criteria for the study population weren’t clearly described and the participants in the study were not representative of those who would be eligible for the intervention [26], and the statistical methods used were inadequately described [26].

3.4. Characteristics of the Interventions and Effects on the Outcomes

A description of the interventions used and their effect on the outcomes is presented in

Table 2. Effects of interventions on the outcome measure.

Author, Year	Performed by	Type of Intervention	HL Measure Tool	Medication Measure Tool	Outcome Measures	Significant Outcomes
Chen et al., 2022 [10]	Medical staff	Continuous education and clinical follow-up	Drug literacy questionnaire compiled by Maniaci et al.	Drug literacy questionnaire compiled by Maniaci et al.	Evaluation of Pharmacological Literacy and complications, and readmission rates were monitored and compared between the two groups.	Before the intervention: no significant differences in drug literacy scores between groups (p > 0.05); after 1 and 3 months: education group scores were significantly higher than the routine group (p < 0.05); rate of administration errors in education group was 5.17%, lower than routine group (15.52%) (p < 0.05); incidences of complications and readmissions: lower in the education group (p < 0.05).
Ng et al., 2017 [25]	Pharmacists	Textual labels with pictograms	REALM-R (Rapid Estimate of Adult Literacy in medicine-Revised Test)	Medication information comprehension scoring criteria	Medical information comprehension scores for different labels for the control group (text only) and experimental group (text and pictogram)	Comprehension scores: higher for the experimental group (p = 0.023)
Grice et al., 2014 [26]	Pharmacy students	Communication facilitated by students	Four Habits Model (FHM) Teach-back, Ask Me 3™, Plain Language, and universal Precautions	-	Resident and student satisfaction with the program, correlations between the students’ use of HL tools and overall residents and students’ satisfaction and between student use of HL tools and resident satisfaction.	Residents’ overall satisfaction with the program, increased understanding of health-related information, confidence in asking healthcare professionals questions about their health, and greater commitment to medication adherence; students highly satisfied with the program. Correlations between previously determined performance level of student communication and resident satisfaction.

. The interventions delivered in the three studies were different and performed by different professional groups. The studies used different measurement tools for HL and medication.

One study was performed by medical staff [10], which involved a total of 116 older adults with coronary heart disease who were randomly assigned to either a routine care group or an educational intervention group. The routine group received standard medication, and the second group received a whole-course medication education method.

This study aimed to identify the most effective HL interventions for medication use among older adults. Results showed that before intervention, no significant differences were observed in drug literacy scores between the two groups (p > 0.05). However, after one and three months post-intervention, the educational group demonstrated significantly higher drug literacy scores (p < 0.05). Another study was performed by pharmacists [25], randomly assigning 50 older adults to either a control group, which received standard text labels on medication, or an experimental group that received text labels supplemented with pharmaceutical pictograms. This study aimed to assess the effectiveness of pictograms in improving the comprehension of medication information among older adults. Results showed that the addition of pharmaceutical pictograms significantly improved the understanding of medication information.

The third study was performed by pharmacy students [26] and included between 147 and 159 senior residents living in a facility over three years. This study aimed to determine the impact of an introductory pharmacy practice experience, in which students were randomly assigned to senior residents and conducted multiple visits to perform assessments and provide general recommendations. Ask Me 3™, the Four Habits Model, and Teach-back are the HL tools that were used to enhance patient–provider communication and understanding: Ask Me 3™ encourages patients to ask three essential questions about their health to promote dialogue and empower them in care decisions; the Four Habits Model provides a structured, relationship-centered approach for clinicians to build rapport, elicit patient perspectives, demonstrate empathy, and ensure understanding; and Teach-back is a technique in which providers ask patients to repeat information in their own words to confirm comprehension, allowing for clarification if needed. All these tools aimed to improve patient satisfaction, confidence, and adherence to medication regimens, and the results showed that the senior residents improved their understanding of health-related information and their commitment to medication adherence.

4. Discussion

This systematic review examined interventions aimed at improving HL with impact on medication use among older adults. Despite the comprehensive search strategy using two major databases, only three studies met the inclusion criteria. Two of these studies presented methodological limitations that affected the replicability of the interventions and the consistency of the outcomes achieved [25,26]. While limited by the small number of included studies, the findings highlight a critical gap in the literature concerning interventions to improve HL and its impact on medication use among older adults. This underscores the need for more robust, high-quality research in this area, especially given the increasing prevalence of chronic diseases and polypharmacy among older adults [7].

The included studies [10,25,26] had shown the importance of HL in older adult population, demonstrating that adequate HL is essential for the right medication management. Older adults with multiple medications prescribed are at increased risk of adverse events and can particularly benefit from tailored HL interventions. The studies explored different strategies to improve patients’ understanding of their medications, including HL tools and educational interventions to improve HL (Ask Me 3™, Four Habits Model, Teach-back) [26], pharmaceutical pictograms [25], and continuous education [10]. The studies seek to demonstrate how HL interventions affect medication adherence, patient satisfaction, reduction in medication errors, and s decrease in complications and hospital readmissions and show that it is necessary to adapt communication strategies to the specific needs of older adults, considering factors such as education level, vision, and familiarity with medication.

The positive outcomes reported in these studies, such as improved medication literacy, greater understanding of medication-related information, enhanced comprehension of health concepts, and better adherence to treatment, are consistent with other research [27,28]. The studies included in this review showed the involvement of different healthcare professionals in HL interventions, all of which demonstrated potential to positively impact older adults’ HL. This multidisciplinary approach aligns with recommendations in the literature emphasizing the importance of engaging diverse healthcare providers in HL initiatives [18,20]. Given the complexity of medication management in older adults, who often experience polypharmacy, interdisciplinary collaboration may be essential for comprehensive HL improvement strategies [18,29,30].

Clinical outcomes from the reviewed studies suggest that improvement of HL can play a key role in enhancing medication management among older adults. The reduction in administration errors, along with fewer complications and hospital readmissions reported by Chen and Yu (2022) [10], indicates that HL interventions may provide significant clinical benefits beyond simply increasing knowledge or comprehension. These findings support those of Pedro et al. (2016) [1], who reported that low HL levels can lead to misinterpretations of medication instructions and poorer health outcomes

For healthcare professionals, these results highlight the importance of assessing older adults’ HL and implementing strategies to improve their understanding of medication and treatment adherence. Simple and effective tools, such as pharmaceutical pictograms and structured educational programs, could be integrated into various healthcare settings [31,32]. Additionally, Grice et al. (2014) [26] demonstrated that involving pharmacy students in patient education could provide learning opportunities for future professionals and practical benefits for older adults, as related in other studies [29,33,34].

To improve HL and optimize health outcomes across diverse populations, it is essential to consider the specific characteristics and needs of each group. The studies analysed in this review suggest some strategies, like defining and tailoring key HL competencies for healthcare professionals according to the target population, adapting communication methods to address factors such as education level, vision impairments, and medication familiarity among older adults, and utilizing HL tools that facilitate information exchange and promote medication adherence [10,25,26]. Ongoing educational programs can strengthen patients’ understanding of their prescribed medication, while training in the interpretation of pictograms proves particularly beneficial for individuals with lower literacy levels. Attention to visual elements such as font size, spacing, and label design ensures readability, and engaging caregivers or family members provides additional support [25]. Employing multiple communication methods tailored to individual preferences, standardizing educational content to correct common misconceptions, and pre-testing HL tools with populations of lower educational attainment further enhances clarity and accessibility [10,18,25,26].

According to our findings, adapting literacy tools to the specific needs of each population can improve comprehension of health-related information, increase adherence to treatments, and consequently improve health outcomes [18].

Our findings are consistent with previous research that emphasizes the crucial role of HL in improving health outcomes among older adults [2,3,6,8]. Low HL levels are associated with misunderstandings about medication, poorer adherence, and increased healthcare utilization [1,6]. Therefore, interventions aimed at improving HL have the potential to significantly improve the quality of life and reduce healthcare costs among older adults.

Although the interventions included in this review suggest potential benefits of improving HL on medication use among older adults, the overall strength of evidence is limited by the methodological quality of the studies such as, for example, the lack of randomization and small samples.

Emerging evidence highlights that HL influences not only medication adherence but also patients’ interactions with healthcare providers, their capacity to manage complex care needs, and overall clinical outcomes, including the complexity of nursing care and trajectory of health status, underscoring the need to consider HL as a multidimensional factor affecting both individual patient experiences and healthcare system demands [35].

While our systematic review identified diverse interventions aimed at improving HL and assessed the impact on medication use in older adults, the current evidence base remains limited and heterogeneous, reflecting broader challenges in this field. Conceptually, these interventions address critical dimensions of HL (functional, communicative, and critical literacy) that influence the ability of older adults to manage complex medication regimens effectively. The differences observed among studies underscore the multifactorial nature of medication management in aging populations, where cognitive decline, sensory impairments, and socio-cultural factors interact.

Practically, these findings imply that successful HL interventions must be multi-dimensional and tailored to older adults’ specific needs [17,18,19]. Health systems and practitioners should consider combining verbal education, written materials optimized for low literacy, and interactive communication techniques to address varied barriers. Policies should promote the development and implementation of standardized HL assessment tools alongside patient education programs adapted for aging populations.

Moreover, the limited methodological rigor and scarce empirical data highlight a pressing need for rigorous, theory-informed research to identify which components and delivery modes yield sustainable improvements in medication adherence and health outcomes. While the search strategy encompassed two predominant biomedical databases, the exclusion of additional databases may have led to the omission of other relevant studies, underscoring the need for broader database inclusion in future systematic reviews. Also, the selected search terms may have contributed to the scarcity of articles found; however, the objective was to study the impact that general interventions to improve health literacy have on the use of medicines, rather than specific interventions. Future studies should incorporate conceptual frameworks from health psychology and gerontology, such as the Health Belief Model or the Capability–Opportunity–Motivation–Behavior (COM-B) model [30], to design and evaluate interventions comprehensively, and given the increasing digitalization of health systems and the growing trend of older adults using the internet and mobile technologies, include e-HL interventions targeting older adults to access health information and manage medications [14].

Although this review focused primarily on general HL interventions, the dimension of digital HL warrants greater attention, given the increasing digitalization of healthcare services [13,14]. Older adults often experience limited access to and familiarity with digital technologies, which may exacerbate their risk of social exclusion and hinder their ability to manage medication through emerging e-health platforms effectively. Recent evidence highlights the importance of digital HL for older adults to safely access, comprehend, and utilize digital health information and services [36,37,38]. However, it has been observed that digital divide and some inequalities due to age still persist in e-health interventions [39].

Considering that the digital transition may represent a new form of social exclusion that particularly affects older adults, it contributes to the exacerbation of health inequities in this vulnerable population. Recent studies reveal that a significant proportion of older adults do not regularly use the internet or digital technologies. This limited digital engagement restricts their access to vital health information and digital health services, which are increasingly integral to modern healthcare delivery [36,37,38]. Future research should therefore incorporate digital literacy components and explore tailored e-health interventions that bridge the digital divide, enabling older adults to benefit from digital healthcare innovations while minimizing health disparities.

In the context of patient-centered healthcare, it is essential to emphasize that evaluating the impact of an intervention after its implementation is fundamental to verify whether the intervention is suitable and effective for the specific community in which it was applied. According to our analysis, this crucial step has been notably lacking in the majority of studies reviewed. Such a gap represents a significant shortfall that compromises healthcare professionals’ ability to make informed decisions when selecting the most appropriate HL interventions for their communities. Without rigorous post-intervention impact assessments, it remains challenging to know the effectiveness and adaptability of interventions, limiting the potential for tailored, community-appropriate solutions that improve HL and truly have an impact on medication use among older adults.

By contextualizing HL interventions within such theoretical frameworks and emphasizing practical strategies, this review provides a foundation for advancing evidence-based approaches that bridge gaps between HL theory, research, and clinical practice for older adults.

5. Conclusions

The systematic review emphasizes the limited evidence available on the effectiveness on medication use among older adults of interventions aimed at improving HL. Although the included studies reported positive results, only three studies met the inclusion criteria, and their methodology did not permit broader generalization. Given the limited number and methodological quality of evidence base, practitioners and policymakers should interpret existing interventions cautiously, underscoring the urgent need for well-designed, rigorous research to establish effective, tailored HL interventions and adapting them to local contexts while supporting ongoing research efforts.

Future studies must focus on closing the research gap regarding effective HL interventions tailored to older adults, to ultimately improve medication safety and health outcomes in this growing population.