Association of health literacy, medication beliefs, and illness perception among older adults with hypertension: a community-based study

Abstract

Background

Health literacy, medication beliefs, and illness perception significantly influence self-care among older adults patients with hypertension. However, the relationship between these factors has not been precisely established in this population. This study aimed to examine the associations of health literacy with medication beliefs and illness perception among older adults with hypertension.

Methods

This cross-sectional study was conducted among 475 hypertensive older adults in Khorramabad City, Iran. Participants were selected using a multistage random sampling method. Data were collected using demographic information questionnaire, the Health Literacy for Iranian Adults (HELIA) questionnaire, Beliefs about medicines questionnaire (BMQ), and Brief Illness Perception Questionnaire (BIPQ). Data were analyzed using SPSS 23 software, by independent t-tests, analysis of variance, Pearson correlation coefficient, and regression analysis. A p-value less than 0.05 was considered significant.

Results

The mean scores (with standard deviations) for health literacy, medication beliefs, and illness perception among the older adults were 57.82 (17.32), 75.14 (6.02), and 38.36 (8.89), respectively. The findings indicated a significant positive correlation between health literacy (overall and across all dimensions) and necessity, overall benefit, and necessity-concern subtraction score (P < 0.001). Conversely, a significant negative correlation was found between health literacy (overall and all dimensions) and concern, overall loss, overall misuse, and illness perception. The regression analysis identified a significant positive relationship between necessity-concern and health literacy (P < 0.001). However, the relationship between illness perception and health literacy was inverse and non-significant (P = 0.158).

Conclusion

The findings indicate that many older individuals face challenges with health literacy, which is closely tied to their perceptions of diseases and beliefs about medications. Therefore, in addition to developing educational programs to improve health literacy, it is crucial to address and correct negative beliefs about medications and perceptions of diseases.

Introduction

The world’s older population is expected to reach 1.4 billion by 2030 and possibly 1.5 billion by 2050 [1]. Similar to other developing countries, the older adult’s population in Iran is also expanding. According to estimates [2, 3], the proportion of individuals aged 60 and over in Iran is expected to reach approximately 27–30% by 2050, representing more than 25 million people .Therefore, as society ages, it becomes imperative to recognize and address the specific problems that this group encounters [4].

Aging is associated with two unpleasant events: physiological decline and deterioration in health status [5]. Aging is a biological process related to changes associated with aging and lifestyle-related diseases, including cardiovascular diseases, with hypertension being at the forefront [6, 7]. Thus, a characteristic of the aging period is the gradual increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP) [8]. Hypertension is not a natural physiological process; rather, it is a consequence of age-related arterial stiffness and changes in arterial compliance due to environmental and lifestyle factors. Hypertension in older adults increases the risk of ischemic heart disease, stroke, and peripheral artery disease. It is also linked to other cardiovascular conditions, such as heart failure, aortic aneurysm, atherosclerosis, and pulmonary embolism [9–11].

A growing body of research suggests that health literacy is a crucial factor in determining self-management behaviors and outcomes in various chronic diseases. Health literacy is defined as “the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions [29].

Hong and Lee [12] and Silva et al. [13] showed in their study that the continuation of treatment for diseases in older patients with hypertension is influenced by their health literacy level. High health literacy contributes to the control of arterial pressure, engagement in physical activities, and a better understanding of health, providing positive long-term outcome. Poor health literacy adversely impacts on illness perception and medication compliance [14]. Research indicates that older adults with hypertension who have a positive perception of their illness and believe in the effectiveness of their treatment are more likely to adhere to medication [15, 16]. “Illness perception” is a term used to refer to an individual’s mental representation and personal ideas about a disease. Patients’ ideas encompass five dimensions, including beliefs about the identity of the disease (its name and symptoms), the causes of the disease, its consequences (impact on areas of life), the course or timeline of the disease, and how to treat or manage the disease [17]. According to Leventhal’s theory, patients adjust their behavior and emotional responses to the illness based on their perception of its nature, causes, consequences, controllability, and duration. Bandura states that understanding illness provides an important framework for examining patients’ beliefs and how its components influence health behaviors [18].

It has been shown that illness perception in individuals with chronic illnesses, can impact their disease management, treatment, follow-up, adaptation, and overall quality of life [19, 20]. Furthermore, the lack of perception of illness leads to a disruption in social-psychological functioning.

As mentioned above, another factor that is influenced by health literacy is medication beliefs. Medication beliefs refer to an individual’s perceptions of the benefits and risks associated with medication, influenced by their understanding of their illness [21]. Sipos et al. (2021) reported that 40% of participants had medication beliefs categorized into essential beliefs and concerns about medication harm, with only 15% expressing low concerns about medication use [22]. Medication beliefs play a crucial role in adherence to treatment among patients with chronic illnesses [23]. Wu et al. (2023) demonstrated that participants with lower medication beliefs exhibited higher self-efficacy, which correlated with increased adherence to medication [24].

Health literacy challenges among older Iranian adults are highlighted in recent evidence. According to a systematic review, over 50% of older adults possess insufficient or marginal health literacy [78].

Health literacy, illness perceptions, and medication beliefs are crucial for enhancing self-care behaviors among older adults with hypertension. Numerous studies in Iran and other countries have assessed health literacy, illness perception, and medication beliefs among older patients with hypertension. These studies mainly focused on the relationships between these factors with dietary and treatment adherence [18, 22, 25–27], self-efficacy [24], and self-care ability [28]. This study was conducted in Khorramabad, the capital of Lorestan Province in western Iran. The city was deliberately chosen for several reasons. First, Lorestan has a higher prevalence of hypertension and cardiovascular risk factors than the national average, largely due to dietary habits, insufficient physical activity, and socioeconomic constraints. Second, Khorramabad reflects a typical urban–rural mixed environment, characterized by moderate-to-low educational attainment and limited access to specialized healthcare—features common to many mid-sized Iranian cities. Finally, the presence of the research team at Lorestan University of Medical Sciences enabled close collaboration with the city’s comprehensive urban health network and contributed to achieving high participation rates.

Given the importance of treatment adherence for the health of older adults the present study aimed to determine the Association of Health Literacy with medication beliefs, and illness perception among older adults with hypertension in Khorramabad city, Iran.

Method

Study design and setting

This study was conducted with a cross-sectional design, and data collection took place from September 2023 to October 2024 (for a duration of 14 months). The lengthy data collection period was due to the large sample size, multi-stage sampling in 12 urban comprehensive health centers, and operational limitations during the post-COVID period; however, all questionnaires were completed at a single point in time for each participant, and no longitudinal follow-up was conducted.

Participants and sampling

The sampling was carried out using a multi-stage random approach (including stratified, cluster, and simple random sampling). Initially, Khorramabad City was divided into three regions: north, south, and center. comprehensive urban health care centers were identified in each region and designated clusters. Subsequently, from each region, four centers were randomly selected, and samples of individuals aged 60 and older were randomly chosen from the lists at each center.

The sample size was calculated based on a similar study (34), 90% power (β = 0.1), and 5% type I error rate (α = 0.05). The sample size calculated was 317 patients. Considering a design effect of 1.5 for cluster sampling, the final estimated sample size was 475 individuals.

Eligible participants were community-dwelling adults aged 60–90 years with a physician-confirmed diagnosis of hypertension (blood pressure ≥ 140/90 mmHg, on at least two separate occasions) for at least six months, documented in the Iranian integrated primary health-care electronic system (SIB).

Exclusion criteria comprised the following: a history of neurological and psychiatric conditions that significantly impact cognition, such as dementia, stroke, Parkinson’s disease, and schizophrenia, as well as severe hearing and visual impairments that affect communication and speech. Participants who either submitted incomplete questionnaires or refuse to cooperate were excluded.

Measures

In this research, a questionnaire with four sections is used to collect data: Sociodemographic questionnaires, Beliefs about medicines questionnaire (BMQ), Brief Illness Perception Questionnaire(B-IPQ), Health Literacy for Iranian Adults (HELIA).

Socio-demographic characteristics

Socio-demographic characteristics included age, gender, marital status, education level and underlying diseases.

Health literacy

Health literacy was measured using Health Literacy for Iranian Adults (HELIA) questionnaire. A validated, 33-question instrument that composed of five subscales as follows: reading health information (4 items), ability to access health information (6 items), appraisal of health information (4 items), Decision making/behavioral intention (12 items), using a five-point Likert scale (always = 5, most of the time = 4, sometimes = 3, seldom = 2 and never = 1),understanding health information (7 items) with a five-point Likert scale ranging from completely difficult (1) to completely easy [29]. The total score range is 33 − 165, where a higher score indicated a desirable level of health literacy. A specific formula was used to convert this score to a range of 0 to 100. Health literacy from 0 to 50 is considered inadequate, from 50.1 to 66 as somewhat adequate, from 66.1 to 84 as adequate, and from 84.1 to 100 as excellent health literacy.

Beliefs about medicines questionnaire (BMQ)

Horne’s Beliefs about medicines questionnaire (BMQ) was used to assess medication beliefs of study subjects. This questionnaire consists of two parts: A: The specific section contains 10 statements and includes 2 subscales. 1- Necessity; it examines the patient’s belief regarding the necessity of the prescribed medications (5 questions). 2- Concern; it assesses the patient’s concerns about the prescribed medications (5 questions). A total score of 5 to 25 is calculated by summarizing the responses from each subscale, with higher scores indicating more negative beliefs. Patients with a necessity score higher than 13 hold strong beliefs, while those with a concern score higher than 13 have serious concerns about their medications. Ultimately, the relatively low necessity–concern differential score (mean 1.59 ± 5.46) observed in our sample indicates that perceived necessity only slightly outweighed concerns about medication. This delicate balance that can easily tip toward non-adherence when concerns predominate. B: The general section consists of 12 statements and includes 3 subscales: 1- Overall harm; it explores people’s beliefs about the harmfulness, addictive nature, and toxicity of medications (4 questions). 2- Overall misuse; it investigates people’s beliefs regarding whether medications are over-prescribed by doctors (4 questions). 3- Overall benefit (4 questions); altogether, the specific and general sections of this questionnaire comprise 22 statements [30, 31].

Illness perceptions

Beliefs about illness were assessed with the Brief Illness Perception Questionnaire (BIPQ) developed by Broadbent et al. and has a high level of reliability and validity. It is designed to evaluate the affective and cognitive representation of the disease [32]. The use of this model has provided a framework for understanding patients’ experiences of symptoms, treatment adherence, and care seeking for a variety of conditions, such as cardiovascular diseases, diabetes, cancer, and asthma [33]. The B-IPQ composed of 9 items that are distributed across 3 dimensions.

These items evaluate consequences, perceived timeline of illness, personal control, treatment control, identity, concern, illness recognition, emotional response and cause of the disease. The first 8 items are scored with a range of 0 to 10, and a maximum total score of 80. Higher scores in patients suggest a greater perception of the disease burden. The 9th item is an open-ended question and inquiries about the three main causes of the disease in order. The validity and reliability of this questionnaire have been confirmed in various studies. In the study by Broadbent et al. (2006), the test-retest reliability over a six-week interval for different questions ranged from 0.42 to 0.75, while concurrent validity was reported between 0.32 and 0.62 [32]. Additionally, the validity and reliability of the Persian version of the questionnaire have been confirmed in Iranian samples, with a Cronbach’s alpha of 0.84 found in a study of 176 patients who had heart attacks [34].

In the current study, the reliability of the instruments was assessed using Cronbach’s alpha. The values were 0.89 for HELIA, 0.85 for BMQ, and 0.87 for B-IPQ, indicating good internal consistency for all questionnaires in this sample.” These statistics confirm the reliability of the instruments for the study population.

Data collection

Eligible participants were contacted by phone and invited to comprehensive health centers. Consent was obtained from those who agreed to participate. After explaining the study’s objectives, the researcher conducted in-person interviews using questionnaires. These interviews took place at urban health care centers and lasted approximately 25 min.

Statistical analysis

All statistical analyses were performed using SPSS for Windows (Version 23.0, IBM, Armonk, NY, USA) [77]. Descriptive statistics, including measures of central tendency and dispersion for quantitative variables, as well as frequency and percentage for qualitative variables, describe the data. The normality of the data distribution was assessed using the Kolmogorov-Smirnov test. With the data showing a normal distribution, independent t-tests and Pearson correlation coefficients were applied. p < 0.05 was considered to be significant.

Results

In this study, 475 older individuals were examined, comprising 225 male (47.4%) and 250 female (52.6%), with a mean age of 66.88 ± 6.72 years years (range: 61 to 90). Most participants were illiterate (27.8%), married (69.7%), and aged 60 to 65 years (53.5%). Additionally, 53.5% lived with their spouses. The demographic characteristics of the older participants are detailed in Table 1.

Table 1.

Demographic characteristics of older participants. N = 475

Categorical variables	Group	Frequency	Percentage
Gender	Male	225	47.4
	Female	250	52.6
Age group (years)	60–65	254	53.5
	66–90	221	46.5
Marital status	Unmarried	47	9.9
	Married	331	69.7
	Widow	72	15.2
	Divorced	25	5.3
Income level	Low	112	23.6
	Medium	278	58.5
	High	85	17.9
Education level	Illiteracy	132	27.8
	Elementary	98	20.6
	Secondary education	93	19.6
	Diploma	89	18.7
	University Education	83	13.3
Presence in social networks	Yes	57	12
	No	418	88
Co-existence	Alone	91	19.2
	With partner	254	53.5
	With children	130	27.4
Comorbidity	Yes	398	83.8
	No	77	16.2

The mean health literacy score was 57.82 (standard deviation: 17.32), suggesting a somewhat adequate level of health literacy. Scores ranged from a minimum of 21.90 to a maximum of 94.58 (Table 2).

Table 2.

The mean of health literacy score and its subscales in participants. N = 475

Subscales	Maximum raw score	Minimum raw score	Mean ± SD
Reading	100	12.50	61.96 ± 20.57
Access	100	00.00	60.64 ± 23.68
Understanding	100	14.29	63.80 ± 19.27
Appraisal	100	12.50	51.01 ± 17.91
Decision-making	100	18.75	51.69 ± 19.19
Total	94.58	21.90	57.82 ± 17.32

Based on the results, the mean score for medication beliefs was 75.14 (SD = 6.02), with a minimum of 60 and a maximum of 93. The mean scores for the dimensions of medication beliefs were as follows: necessity 18.61, concern 17.01, overall harm 13.17, overall misuse 10.62, and overall benefit 15.72. Furthermore, the difference between the necessity and concern scores was 1.59 (Table 3).

Table 3.

The mean of medication beliefs and its subscales in participants. N = 475

Subscales	Maximum raw score	Minimum raw score	Mean ± SD
Necessity	25	14	18.61 ± 2.86
Concern	24	10	17.01 ± 3.18
Overall harm	20	4	13.17 ± 3.03
Overall misuse	20	4	10.62 ± 3.14
Overall benefit	20	12	15.72 ± 2.19
necessity - concern	14	-10	1.59 ± 5.46
Total	93	60	75.14 ± 6.02

The mean score of illness perception among participants was 38.36 (SD = 8.89), with scores ranging from a minimum of 17 to a maximum of 60.

The Pearson correlation test revealed a significant positive correlation between overall health literacy and its dimensions (reading skills, access, Understanding, appraisal, decision-making) with necessity, overall benefit, and the necessity-concern difference (P < 0.001). Conversely, there was a significant negative correlation between overall health literacy and its dimensions with medication beliefs (overall), concern, overall harm, and overall misuse (P < 0.001). Furthermore, a significant negative correlation was found between overall health literacy and its dimensions with illness perception (P < 0.001) (Table 4).

Table 4.

Correlation between overall health literacy and its dimensions with dimensions of medication beliefs and illness perception. N = 475

Variable	Reading	Access	Understanding	Appraisal	Decision making	Total Health Literacy
Total medication beliefs	-0.14	-0.21	-0.31	-0.10	-0.13	-0.14
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Necessity	0.54	0.53	0.54	0.60	0.59	0.65
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Concern	-0.30	-0.22	-0.28	-0.41	-0.42	-0.39
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Overall harm	-0.26	-0.26	-0.26	-0.31	-0.35	-0.33
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Overall misuse	-0.38	-0.37	-0.34	-0.37	-0.41	-0.43
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Overall benefit	0.47	0.48	0.50	0.51	0.55	0.58
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Necessity-concern	0.44	0.44	0.45	0.55	0.55	0.57
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*
Total illness perception	-0.54	-0.54	-0.55	-0.56	-0.51	-0.63
	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*	P < 0.001*

p < 0.05

The results of the multiple linear regression indicated that after controlling for variables such as gender, age, social media presence, underlying health conditions, marital status, income level, education level, and cohabitation, a direct and significant correlation was observed only between necessity-concern and health literacy. Specifically, for each unit’s necessity-concern score, health literacy increased by 0.247 units (P = 0.003). In contrast, an inverse and non-significant correlation was noted between disease perception and health literacy (P = 0.158). (Table 5).

Table 5.

Multivariate regression of the relationship between drug beliefs and disease perception with health literacy. N = 475

Variable	Beta (b) coefficients	Standard Error	Standardized Beta	t	95% CI	P Value*
Necessity-concern	0.247	0.082	0.078	3.020	0.086 to 0.408	0.003*
Illness perception	-0.076	0.054	-0.039	-1.413	-0.182 to 0.030	0.158
Gender	-0.635	0.829	-0.018	-0.766	-2.261 to 0.991	0.444
Age	0.020	0.067	0.007	0.291	-0.111 to 0.151	0.771
Presence in social networks	-2.820	1.347	-0.053	-2.094	-5.461 to -0.179	0.037
Comorbidity	-1.179	1.089	-0.025	-1.083	-3.315 to 0.957	0.279
Marital status: Unmarried	-0.787	1.535	-0.014	-0.512	-3.796 to 2.222	0.609
Marital status: Widow	1.339	1.445	0.028	0.926	-1.493 to 4.171	0.355
Marital Status: Divorced	0.595	1.759	0.008	0.338	-2.855 to 4.045	0.735
Income level: Medium	0.883	0.879	0.025	1.005	-0.840 to 2.606	0.316
Income level: High	2.975	1.213	0.066	2.453	0.598 to 5.352	0.015
Education level: Elementary	10.486	1.073	0.245	9.775	8.383 to 12.589	P < 0.001
Education level: Secondary	19.223	1.125	0.441	17.088	17.018 to 21.428	P < 0.001
Education level: Diploma	29.688	1.355	0.669	21.910	27.033 to 32.343	P < 0.001
Education level: University	39.646	1.903	0.777	20.831	35.916 to 43.376	P < 0.001
Co-existence: Alone	1.090	1.375	0.025	0.793	-1.605 to 3.785	0.428
Co-existence: With children	0.856	0.937	0.022	0.914	-0.980 to 2.692	0.361

p < 0.05

Discussion

This study examines the relationship between health literacy, medication beliefs, and illness perception in older individuals with hypertension. The findings revealed that older Iranian adults with hypertension have inadequate health literacy. These results align with those obtained by Powell et al. 2007, Rahmati et al. 2019, Sabooteh et al. 2019, Khodaparast et al. 2021, and Ghanbari-Taluki et al. 2023 [35–39]. The studies indicated that the health literacy levels of the examined individuals found to be not quite sufficient. The low health literacy among participants can be attributed to various psychological, physiological, and economic changes associated with aging. However, the recent rise in chronic diseases and hypertension underscores the urgent need for self-care skills and regular screenings, highlighting the importance of health literacy in this demographic. Consequently, the inadequate health literacy among the older adults in Khorramabad serves as a critical alert for health system officials [40]. In contrast to the findings of the present study, research by Gazmararian et al. (2003), Kim et al. (2004), Javadzade et al. (2013), and Seyedoshohadaee et al. (2016) indicates a high level of health literacy [41–44]. Discrepancies between the results of these studies and the current study may stem from differences in the research population as well as cultural and social variations among the communities studied.

According to the results, participants scored the highest on the dimensions of understanding, reading abilities, and access to health information. Conversely, the lowest score was found in the dimensions of appraisal of health information and decision-making indicating a broader issue of critical thinking and analytical skills in health contexts, necessitating comprehensive educational strategies to address these gaps. These findings are consistent with previous studies [38, 45, 46]. High scores in understanding indicate that participants can effectively interpret health information. This capability is important, as the ability to comprehend medical instructions, health promotion materials, and information of disease prevention directly influences individual health outcomes. Furthermore, those who can comprehend intricate health concepts are more inclined to adopt preventive health behaviors and proactively oversee their medical conditions.

Participants with proficient reading abilities are capable of handling various health-related texts, which is crucial in the current healthcare environment, where people frequently need to analyze online resources, mobile health applications, and informational pamphlets. By implementing targeted strategies to improve reading proficiency, individuals could become more empowered, allowing them to make well-informed choices regarding their health.

Enhanced access in this study indicates that participants likely have the necessary resources to obtain health information. Addressing access barriers is critically important, especially in underserved populations, to ensure that all individuals have the opportunity to improve their health literacy.

Participants in this study showed inadequate performance in assessing health information. This dimension pertains to the ability to evaluate the validity and relevance of health information. Low scores in this area may result in misinformation and suboptimal health decisions.

Decision-making dimension is closely related to individuals’ abilities to use health information for personal health decisions effectively. The participants’ poor decision-making performance indicates that despite having access to health information and understanding it, they may struggle to apply this knowledge in practical scenarios [47]. This gap may be related to a lack of confidence, inadequate support systems, or insufficient skills to assess the potential outcomes of various health-related options.

In the present study, the overall score of medication beliefs among the older adults was found to be high. In other words, the older adults had a weak belief regarding the effectiveness of medications. These results are consistent with the findings of Esna-Ashari et al. and Olorunfemi and Ojewole [48, 49]. Individuals’ beliefs about medications have two aspects: 1- specific aspect, 2- general aspect. The specific aspect pertains to individuals’ beliefs about prescribed medications. This section is divided into two subscales: (a) necessity and (b) concern. The results of this study revealed a high necessity score among the older adults, suggesting that they regard the use of medications as essential and beneficial for their health. Consistent with these findings, Esna-Ashari et al. (2023) and Asayeshi et al. (2017) also reported a high average necessity score in patients with hypertension [27, 48].

The mean score on the concern subscale was notably high, indicating significant concerns about dependence, medication toxicity, and long-term side effects of drugs. These findings align with previous research’s [27, 48, 50–52], all of which highlighted considerable anxiety among patients regarding their medication use. the subtraction score (necessity-concern) serves as a criterion. The subtraction score (necessity-concern) serves as a criterion, with a higher score indicating a stronger belief in the usefulness of medications. The results of the present study revealed that the necessity-concern subtraction score was low, suggesting that older individuals hold weak beliefs regarding the effectiveness of their medications. Indeed, while they strongly affirmed the importance of medications for their health, they also expressed concerns about the side effects of drug use, including dependency, drug toxicity, and long-term side effects. Consistent with these findings, similar results were reported by Fernandez-Arias et al., De Vries et al., De las Cuevas et al., De las Cuevas et al., and Esna-Ashari et al. [48, 53–56]. The necessity-concern subtraction score is significantly associated with medication adherence under various conditions. Foot et al. demonstrated in their meta-analysis that a low necessity-concern subtraction score, particularly in cases of hypertension, correlates with medication non-adherence [57].

The scores for the overall harm and overall misuse subscale among participants in the study were notably high. Consistent with these findings, Wei et al. Fernandez-Arias et al. and Rajpura and Nayak reported similar results [53, 58, 59]. In this regard, AlHewiti indicated that participants with elevated scores on the overall harm and overall misuse subscale exhibited stronger beliefs about medication overuse, its harmful effects, addictive properties, and the issue of over-prescription [26]. Furthermore, various studies have indicated that poor medication adherence correlates with the overall harm and overall misuse subscale, with some research identifying it as a primary factor contributing to treatment failure in patients with hypertension [60–63].

Participants in this study demonstrated a high mean score on the overall benefit subscale. These findings are consistent with those of Ramström et al. (2006) and Wei et al. (2017) [58, 64]. In summary, this study revealed that older adults recognized the advantages of medication while simultaneously harboring concerns about it. This observation highlights a crucial point: older individuals may occasionally decide to discontinue treatment [64].

The illness perception score among the participants was moderate. These results are consistent with those reported by Van der Ende-van Loon et al. (2022), Arab Sheibani and Seyedabadi (2021), Bagherian et al. (2019), and Fathi et al. (2013) [65–68]. Research has indicated that a more negative disease perception (reflected by a higher questionnaire score) correlates with reduced quality of life in patients with hypertension [69]. Consequently, the moderate disease perception observed in this study may contribute to diminished quality of life for older individuals with hypertension. Taheri-Kharameh et al. (2016) reported similar findings with a moderate level of disease perception in patients with hypertension. Their research also identified disease perception as the most significant predictor of adherence to treatment regimens [18].

The study’s findings revealed a positive and significant correlation between health literacy (total and its dimensions) and necessity, overall benefit, and necessity-concern subtraction. These results indicate that an increase in health literacy correlates with higher mean scores for necessity, overall benefit, and the difference between necessity and concern. Although reading and understanding remained significantly correlated, their associations with medication beliefs were relatively weak, suggesting that mere comprehension is inadequate when cultural narratives strongly frame medicines as harmful. In contrast, all five dimensions showed strong negative correlations with illness perception. Appraisal and decision-making demonstrated the strongest positive associations with perceived medication necessity and the necessity–concern differential, while also showing the strongest negative associations with concerns, perceived harm, and misuse. These findings indicate that the capacity to critically assess health information and convert it into behavioral intentions is a key determinant of favorable medication beliefs among older Iranian adults. This suggests that the ability to critically appraise health information not only fosters rational treatment beliefs but also reduces emotionally driven perceptions of hypertension as a threat—an observation with clear relevance for intervention strategies. Furthermore, the findings revealed a significant negative correlation between overall health literacy and its dimensions with medication beliefs (total), concern, overall harm, and overall misuse. Specifically, as health literacy rises, the mean scores for medication beliefs (total), concern, overall harm, and overall misuse decrease. Consistent with the present study, Kale et al. (2015) showed a positive relationship between overall health literacy and its dimensions with necessity, overall benefit, and necessity-concern subtraction. Additionally, these researchers found that low health literacy is significantly associated with heightened concern and overall harm related to medications [70]. In another study, Federman et al. (2013) indicated that low health literacy is related to negative medication beliefs in older adults patients with asthma [71]. The researchers found that low health information literacy and processing skills lead to negative medication beliefs (concern, overall harm, and misuse) in individuals with low health literacy. Given that mental preparedness regarding chronic illnesses, like hypertension, often depends on the search for and processing of information, a significant correlation between health literacy and medication beliefs among the older participants in this study was anticipated. Individuals with low health literacy who suffer from chronic conditions, such as hypertension, typically have limited access to credible information sources, resulting in poor understanding and evaluation of their illness. Consequently, they often do not acknowledge the chronic nature of their condition, leading to a more negative emotional representation of their disease, including increased concerns about their health [70–76]. The study also revealed that the lowest scores among the dimensions of health literacy were in appraisal, decision-making, and access. Therefore, the findings of this study suggest that inadequate health literacy, particularly in access and evaluation, has contributed to the formation of erroneous medication beliefs, resulting in increased concern, perceived overall harm, and general misuse of medications. This suggests that inadequate health literacy among the older adults, particularly in the dimensions of access and evaluation, has contributed to the formation of misguided medication beliefs, which include increased concern, perceived overall harm, and misuse.

This study was conducted in Khorramabad, Iran, a city with unique cultural and socioeconomic characteristics that may influence health literacy and beliefs about medications and illness. For instance, cultural attitudes toward healthcare and traditional remedies, as well as limited access to health education resources in some communities, may shape the findings. Future studies should include diverse regions to enhance generalizability and explore how cultural factors influence these associations.”

Conclusion

This study shows that among Iranian older adults with hypertension, health literacy significantly and independently enhances medication beliefs(higher perceived necessity, lower concerns), but has a limited effect on illness perception.older individuals with higher health literacy had greater confidence in their medications and perceived their illnesses as less threatening. Individuals who have a better understanding of their health conditions are more likely to adhere to their medications and treatment plans. Conversely, a negative perception of illness and medications can lead to non-adherence to treatment and, consequently, an increase in disease complications. Practical and policy implications can be as follows: Simple, low-cost, face-to-face health literacy interventions—such as pictorial guides, teach-back methods, and plain-language medication reviews—should be promptly expanded in all primary health centers for adults aged 60 and older to quickly improve adherence to antihypertensive treatment. Reducing perceived illness threat requires more than education; peer storytelling, patient testimonial videos, and brief motivational interviewing targeting fear of stroke and “chemical drugs” must be added. Make annual brief health-literacy screening + 5-item BMQ mandatory for older hypertensive patients. Train GPs, nurses, and community health workers on the Necessity–Concerns Framework. Update national hypertension guidelines to mandate combined cognitive and emotion-focused interventions.

Limitations and suggestions for future research

Although this study has provided valuable results, there are also limitations. The major limitation is the cross-sectional nature of the study, which precludes any causal or temporal inferences. We can only describe associations at a single point in time; it remains unknown whether higher health literacy leads to more positive medication beliefs and less threatening illness perceptions, or whether individuals with more positive beliefs subsequently seek out and acquire higher health literacy. Longitudinal or interventional studies are needed to establish directionality and causality. Participants were recruited from urban comprehensive health centers in Khorramabad and had to attend in person for interviews. Older adults with severe mobility limitations, very low literacy, profound cognitive impairment (even if not formally diagnosed), or those who distrust the health system may have been under-represented. Furthermore, all measures (health literacy, medication beliefs, illness perception) relied on self-report, introducing the possibility of social desirability bias and recall bias. Future research may benefit from combining self-report tools with objective assessments or caregiver reports to strengthen accuracy.

Additionally, other factors such as economic status, access to health services, and social support can also influence health literacy and medication beliefs and should be examined in future research.

Abbreviations

SBP

Systolic blood pressure

DBP

Diastolic blood pressure

HELIA

Health Literacy for Iranian Adults

BMQ

Beliefs about medicines questionnaire

BIPQ

Brief Illness Perception Questionnaire

Authors’ contributions

A.B: investigation and writing the original draft. A.B: Supervision and writing manuscript. K.K: Scientific Consultation and reviewing the manuscript. R.M: Data analysis.

Funding

No funding.

Data availability

The datasets of current study are not publicly available due to the protection of subject privacy; however, they may be obtained from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This study was performed in accordance with the principles of the Declaration of Helsinki. Ethical approval was obtained from Lorestan University of Medical Sciences Ethics Committee (approval number:IR.LUMS.REC.1402.154 ). All participants were apprised of the nature and objectives of the survey, and signed Written informed consent prior to data collection. Involvement in this study was voluntary and researchers maintained the confidentiality of the data.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.