1. Introduction
The ageing of the global population is a widespread phenomenon, and currently, it seems to be happening faster than in the past. The World Health Organization estimates that the proportion of individuals older than 65 years in 2000 is expected to more than double by 2050 [
1]. The number of older individuals and older couples living alone is also growing because of rapid changes in social structures. Moreover, the number of medications that older adults take by themselves has also increased. Households comprising only older adults require more socioeconomic attention to improve their healthcare as well as financial status for better quality of life [
2,
3].
Ageing is accompanied by several physical and mental issues not experienced by younger individuals, such as a decline of physical and mental capabilities, including worsening sight and hearing, increased physical frailty, and difficulty adapting to rapid social changes. They also experience changes in their pharmacokinetic and pharmacodynamic characteristics [
4,
5]. Furthermore, the prevalence of chronic diseases increases with age. More than half of older adults have three or more chronic diseases; therefore, older adults attend clinics often and take prescribed medications. They also tend to use non-prescribed or over-the-counter (OTC) medications to relieve various symptoms without first obtaining advice from a clinician [
6,
7]. Because of the increase in the older population and their chronic conditions, older adults have become the largest consumers of prescription and OTC drugs [
8]. They are more vulnerable to adverse drug effects and are exposed to the risks associated with using multiple or inappropriate medications [
4,
9,
10]. Taking many types of medications can cause confusion, thereby leading to serious health consequences or even fatalities due to improper use [
11].
Self-medication refers to individuals recognising their own symptoms, making a self-diagnosis, and choosing and using medications by themselves [
12,
13]. Self-medication with OTC drugs can be an economical treatment choice; furthermore, OTC drugs are legally accessible at pharmacies [
14,
15]. However, this creates concerns because older adults are more likely to misuse medications and may have difficulties in understanding the adverse effects associated with the medications they choose to manage their symptoms with [
12,
14].
Older individuals comprise a vulnerable group with limitations in acquiring and understanding drug safety information [
16]. For example, they often have difficulty accessing information through the use of mobile devices, computers, and the Internet; moreover, they often have vision and/or hearing problems or mental factors that act as barriers to the acquisition of information [
17,
18,
19,
20]. Therefore, safe medication use should be emphasised and needs to be investigated in this group of individuals.
We surveyed older individuals to investigate their medication habits and to identify their unmet needs associated with safe medication use. The knowledge, attitude, and practice (KAP) model was used to develop a questionnaire for these individuals. The original KAP survey has been widely used to obtain health behaviour information [
21,
22,
23]. Although knowledge is related to attitude and practice, it does not perfectly predict behaviours [
24,
25]. Therefore, it was necessary to determine how interactions among these factors affect human behaviours. Knowledge represents more than having information; rather, it refers to the ability to collect, maintain, and use information [
26]. Existing studies have shown that knowledge can be gained through education and experience and that attitudes—including the concepts of perceptions, feelings, beliefs, and behavioural tendencies—can be changed through health education. Practice refers to applying the acquired knowledge to actions [
26,
27,
28].
Based on these attributes, we adopted the KAP model to analyse knowledge gaps, cultural beliefs, and behavioural patterns among older adults [
29]. This study surveyed experiences, education, and knowledge regarding safe medication use among older adults and analysed how medication safety education can affect their KAP.
2. Materials and Methods
2.1. Study Design and Data Collection
This was a cross-sectional study designed to examine older adults’ drug use and to evaluate the relationships among their KAP and medication safety habits.
We enrolled adults aged 65 years or older who were able to participate in social activities and excluded those who were unable to live independently, who could not ambulate without assistance, and those with severe cognitive impairments. The survey included older adults living in various regions, such as the capital city, urban areas, and rural regions of Korea to ensure a data sample with various social backgrounds. To recruit participants, we visited senior community welfare centres and retail pharmacies and conveyed the purpose and scope of this study. The questionnaire was distributed in paper form, considering that older adults are generally not familiar with social networking tools. All participants provided written informed consent forms, and we collected the data from May to June 2017. All procedures were approved by the Institutional Review Board of Korea University (KU-IRB-17-58-P-1). This study was conducted in accordance with the ethical guidelines stipulated in the Declaration of Helsinki.
2.2. Survey Design
The survey had two parts and comprised a total of 44 questions. The first part collected the participants’ demographic data, their experiences with medication safety education provided by senior organisations or local healthcare centres, their satisfaction with education, and their actual OTC drug use habits. The second part investigated the effects of knowledge on their attitudes and practices associated with medication safety. Furthermore, the second part included 25 questions: 10 were knowledge-based; eight were attitude-based, and seven were practice-based. The medication safety education programme referred to in the questionnaire was created by the Korean Pharmaceutical Association and is provided to senior organisations and local healthcare centres [
30].
Using the KAP model as a foundation for our questionnaire, we aimed to identify the relationships among KAP and medication use by older individuals. Except for the questions on demographic characteristics, the respondents answered questions using a 5-point Likert scale ranging from “strongly disagree” to “strongly agree”, with a higher total score indicating higher levels of KAP associated with medication use.
Four investigators validated and revised the questionnaire. Cronbach’s α test was conducted to assess the internal consistency of the questionnaire, with the following results: knowledge, 0.607; attitude, 0.759; and practice, 0.612. A Cronbach’s α coefficient of 0.6 or more indicates an acceptable internal consistency [
31].
2.3. Statistics Analysis
We only analysed the responses to the questionnaires when more than half of the questions were answered and excluded questionnaires from the analysis when the respondents did not include information about their age or sex.
Categorical variables such as sex, residential area, age group, residence type, and method of taking medication are presented as frequencies and percentages. Self-medication habits and experiences with medication safety education are also represented as frequencies and percentages. Continuous variables are presented as means and standard deviations (SD). Pearson’s correlation coefficient was used to identify the interrelationships between knowledge and attitude, knowledge and practice, and attitude and practice. The R-value of each item was interpreted as a moderate correlation of 0.4 or more, which was generally considered to be significant [
32]. A t-test was performed to verify the differences in KAP based on educational experience.
Statistical significance was set at p ≤ 0.05 and determined by bilateral test using IBM SPSS Statistics software (version 25.0; IBM, Armonk, NY, USA).
4. Discussion
In the current ageing society, older adults form a large part of the worldwide population. As they start to live independently as “old people,” their quality of life is influenced by new major issues [
33].
In this study, we surveyed independently living older adults to investigate their medication habits and the factors that affect their safety when using medications. The characteristics of the individuals enrolled in this study were similar to those enrolled in the study by Kharicha, who assessed the health risks of older adults in the United Kingdom and found that 37% of the population 65 years and older lived alone [
34]. We found that most older adults took their medications by themselves and that self-medication without assistance from others decreased their treatment adherence. This result is comparable to that reported in a study by Park et al., which was conducted on older adults with chronic diseases who were living alone [
35].
These results imply that older adults can become isolated from information about medication. The physical and mental health levels of older adults living alone were poorer than those of older adults living with their families [
35,
36,
37]. One study also reported that many ageing individuals were using medication that had expired because they had difficulty reading the expiry date on the package label [
38].
Current society is rapidly changing, and older adults tend to have difficulty in coping with changing environments, often due to health problems affecting their physical and cognitive functions. They are less adaptable to new trends in acquiring information and more vulnerable to various diseases and discomforts. In other words, ageing is a factor that can prevent sufficient access to media and updated information. Therefore, although proper drug use is crucial for the wellbeing of elderly individuals with chronic diseases or geriatric-related pain, they often lack knowledge about medication because of their difficulties in obtaining information.
Individuals can obtain OTC drugs because they are more accessible than prescription drugs and can be purchased in large quantities at one time; therefore, these medications are often stored for long periods. During this study, we selected analgesics, external usage formulations such as patches and ointments, and gastrointestinal drugs because they are the most frequently consumed OTC products in Korea [
39]. We showed that these OTC drugs are used often by older adults, which is consistent with the findings of the study by Amoako on older adults and their self-medication practices [
13]. Furthermore, most respondents reported the habitual use of these OTC drugs more than once per week or more than once per month. There are some concerns about the health management and OTC drug use practices of older adults because some of them indicated that their medications include nonsteroidal anti-inflammatory drugs or H2 blockers listed in the Beers criteria [
40,
41,
42,
43]. The Beers criteria, which were initially developed by an expert consensus panel in 1991, are the most widely used criteria for determining medications that are inappropriate for use by older individuals due to their high risk of adverse drug events [
41]. Furthermore, because of their propensity to use OTC drugs arbitrarily, older adults need to have accurate knowledge of their medications to avoid serious risks.
This study aimed to investigate the awareness of safe medication use in older adults using a questionnaire developed based on the KAP model and to confirm the correlations among each element of KAP. In this model, K represents knowledge of diseases and medications, A represents the attitude toward those diseases and medications, and P represents practice or preventive actions to protect against diseases and unsafe medication use [
27]. The results confirmed that knowledge related to the safe use of medications positively affected attitudes and practice, which was in line with the results of the study by Hope that investigated the associations among adherence, knowledge, and skills of patients with congestive heart failure and confirmed that the medication use behaviours of the subjects improved after they received proper education [
44]. Several studies have revealed that older adults often lack knowledge about side effects, usage methods, and dosage of their medication; however, most individuals are aware of the purpose of their medication [
45,
46,
47]. Additionally, Tesfamariam et al. reported that poor knowledge was one factor that resulted in inappropriate OTC medication use [
47]. These results emphasise the importance of and the need for medication safety education, especially among older adults using OTC drugs. Furthermore, Kim et al. reported the impact of education on preventing medical errors [
48]. These findings have great implications for the importance of drug safety education. Therefore, it is necessary to provide this education and to reinforce its adherence for it to become effective.
In this study, although the survey participants had a little safe drug use education experience, they reported high satisfaction with that education and indicated that they prefer education in the form of on-site lectures and audio–visual materials rather than other methods such as textbooks. Some studies also found that education using audio–visual methods is more effective than that using brochures or pamphlets [
49,
50,
51]. Therefore, these preferred types of educational materials need to be developed and adapted to help ensure the safety of these individuals.
Few questionnaires have used the KAP model for medication safety practiced by older adults. Therefore, this study is valuable for two reasons: First, the survey was conducted by directly contacting older adults in various regions. Second, this study revealed actual OTC medicine use habits and the importance of knowledge among older adults. Most importantly, we confirmed that older adults also recognise their need for education and are able to identify their preferred form of education.
This study was limited by its use of a paper survey rather than one available through the use of newer tools such as multimedia. However, because the questionnaire was paper and administered face-to-face to the respondents, it may be more suitable for older adults who find technology to be challenging.