Mediating effect of health literacy on social support and self-care ability in older patients undergoing percutaneous coronary stent implantation

Introduction

Coronary heart disease (CHD) is characterized by atherosclerosis, which leads to coronary artery stenosis or even occlusion, and then myocardial ischemia, hypoxia or necrosis (1). By 2020, the number of patients with cardiovascular disease in China has reached 330 million. Among them, the number of with CHD patients is as high as 11.39 million (2). In addition, there are absolutely more and more cases of risk factors, and the mortality rate of CHD in China may increase further in the future (3). Therefore, the physiological and economic burden of CHD has become an important public health problem in China.

At present, percutaneous coronary stent implantation (PCI) is the main method for CHD treatment (4). The diagnostic criteria for CHD treated by PCI in The Chinese Guidelines for Percutaneous Coronary Intervention (2012 Brief Edition), including the stenosis degree of left main artery exceeding 50%, proximal anterior descending branch stenosis over 70%, lesions with 2 or 3 branches, reduced left ventricular function, and extensive myocardial ischemia (5). PCI can only relieve chest distress, chest pain and other uncomfortable manifestations caused by coronary artery stenosis or obstruction. However, it cannot fundamentally prevent adverse cardiovascular events Adverse cardiovascular events such as second restenosis and thrombosis to occur (6). Postoperative patients still need to take long-term anticoagulant drugs, and pay attention to diet and regular exercise to prevent secondary coronary artery stenosis (7). So, health literacy and self-care ability of older patients undergoing PCI are required.

Health literacy refers to the process in which people acquire, understand and accept health information and services, and people can use them to make correct judgments and decisions to promote physical health (8). With the transformation of modern medical mode, the pursuits of the patients are not only survival, prolongation of life and relief of symptoms, but the higher quality of life. Health literacy plays an important role in improving patients’ awareness and empowering them, and limited health literacy has the potential to cause serious problems. For example, Savitz et al. (9) and Shamim et al. (10) have found that patients with poor health literacy are more likely to make clinical decisions with conflicts, and individuals with poor health literacy tend to lack relevant health knowledge, possibly. As a result, they lack self-confidence in self-care ability, and it is difficult for individuals to adhere to self-care ability (11). Self-care ability is a multi-dimensional concept related to health confirmed in many studies, and is a practical activity used by individuals to maintain health (12). With the increasing age of the older persons, the complications such as dizziness, numbness of hands and feet, and fatigue after PCI are easy to cause many physiological and psychological changes. Further, patients may underestimate their ability, leading to hygiene habits that harm physical and mental health (13). So, self-care ability can serve as a very important health resource and become a decisive factor in the management of daily life (14). Furthermore, as a health resource, self-care capacity can be a part of health care to promote self-responsibility, enabling individuals to care for themselves in any health condition.

Social support as one of the important intermediary factors of psychological stress and health status, specifically refers to giving individual spiritual and material help and support from all aspects of society including family, relatives, friends, colleagues, colleagues, partners, party, trade unions and other organizations. It buffers stress, maintains good emotional experience, affects the patient to choose treatment options, and improve treatment compliance and life quality (15). Research suggests that individuals with inadequate social support will also show poor levels of self-care competence (16). There are interconnections health literacy and social support. In previous studies, health literacy was found to be directly related to social support, and indicated that improving the health literacy of caregivers effectively improved their care ability (17,18). This study initially assumed the interactive relationship between health literacy and social support and self-care related behaviors based on the established principles of health cognition and behavior (e.g., the common sense model of self-regulation) (Figure 1) (19). The hypothesis of this study is that by improving their health literacy, good social relations and self-care ability of patients after PCI, which can help them to reverse or delay the disease process and improve their quality of life after surgery. We present this article in accordance with the STROBE reporting checklist (available at https://cdt.amegroups.com/article/view/10.21037/cdt-24-50/rc).

Figure 1 Hypothetical model of the interaction between health literacy and social support and self-care related behaviors in older patients after PCI. PCI, percutaneous coronary stent implantation.

Methods

Study design

This cross-sectional study was conducted between December 2021 and March 2022.

Patients

A total of 260 older patients who underwent PCI in our hospital were included in this study using a convenience sampling method. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013), and it was approved by the Ethics Committee of The General Hospital of Ningxia Medical University (No. 2018-336). All patients signed informed consent forms before participating in this study.

Inclusion criteria: (I) CHD diagnosis treated by PCI (5); (II) patients aged at least 60 year-old and able to carry out daily communication; (III) patients and their families understood and accepted to participate in the study voluntarily.

Exclusion criteria: (I) unable to cooperate; (II) severe cognitive and mental disorders; (III) other serious complications.

Sampling methods

Sample number requirements were based on multi-factor analysis. The sample number should be 5–10 times than the maximum number of items in the scale. Among them, the number of items in the self-protection capacity scale was the largest, with 43 items. Therefore, the minimum sample number was 215, and the 10% invalid answer rate was considered. Therefore, at least 237 questionnaires were issued. In this study, convenience sampling method was used. A flow diagram to report the number of participants at each stage was provided in Figure 2.

Figure 2 The flow chart to report the number of participants at each stage.

Chronic disease health literacy management scale (HeLMS)

Chronic disease HeLMS was designed by Jordan et al. (20), which was translated and improved by Sun HL, a research scholar at Fudan University, China. After translation, revision and reliability evaluation of the HeLMS scale, the coefficient of α-Cronbach was 0.86–0.95. There are 24 entries with four dimensions, including information acquisition, communication and interaction, improved health and financial support. Among the items, there are 5 choices (1–5 points, positive items). “1” means completely impossible, “2” means very difficult, “3” means slightly difficult, “4” means a little more difficult, and “5” means not difficult. The highest score is 120 points, and the lowest score is 24 points. The higher the score, the higher the level of health literacy.

Exercise of self-care agency scale (ESCA)

The scale was designed by American scholars Kearny and Fleischin 1979 according to Orem’s self-care theory, which was the most commonly used tool in China to measure the level of self-care ability. In 2000, Wang and Lafrey translated it into Chinese version, and modifications were made in the wording of items to make them more meaningful for the older women (21). The internal consistency of the Chinese scale is evaluated as 0.86–0.92, and the coefficient of α-Cronbach is 0.77–0.80. There are 43 items, including self-care concept, self-care responsibility, self-care skills and health knowledge level. The score of each item is 0–4 points, with a total score of 172 points, of which 11 items are in reverse score. The score of 116–172 is in high level of self-care ability for exercise, the score of 58–115 is at the medium level, and the score of 0 to 57 is at a low level (22).

Social support rating scale (SSRS)

Social support was measured with the Chinese Social Support Rating Scale (23), which consists of 10 items divided into three dimensions: objective and subjective support and use of social support. Higher scores indicated better social support from family, friends, and colleagues. Each item was scored differently: maximum scores of 4 for items 1–4 and 8–10, 20 for item 5, and 9 for items 6 and 7. The total score was 66 points, and the score of >45 was divided into high level. The coefficient of α-Cronbach in the scale was 0.89–0.94, and the reliability of remeasurement was 0.92.

Data collection

Through the retrieval and reading of relevant literature, the demographic and health history questionnaire was designed by ourselves. The data contained questions on gender, age, type of medical insurance, whether there were other chronic diseases, family history of CHD, smoking history, medication history, etc. Then, questionnaires in paper were sent to 260 patients with PCI in our hospital. A total of 260 questionnaires were sent out in this study, and 256 were returned. After removing seven invalid questionnaires, there were 249 valid questionnaires remaining, with an effective rate of 97.26%. After the questionnaire was sorted out, a database was established.

Statistical analysis

Statistical Product Service Solutions (SPSS) 24.0 and Analysis of Moment Structures (AMOS) 22.0 (SPSS Inc., Chicago, IL, USA) were used for statistical analysis of the data, and the demographic and health history data were described by frequency and percentage. The status quo of health literacy, social support and self-care ability were described by means ± standard deviation (SD). Pearson correlation method was used to analyze the correlation of health literacy, social support and self-care ability. AMOS 22.0 software was used to explore the interaction path between self-care ability, social support and health literacy. Bootstrap method was used to examine the mediating effect between health literacy and social support and self-care ability. The test level was α=0.05.

Results

Demographic and health history

In this study, demographic and health history of patients with PCI was evaluated, such as sex, age, level of education, occupation status, smoking, diet, per capita monthly household income, residence, health care type, associated with other chronic diseases, family history of CHD, the number of PCI or PCI brackets, type of medication taken for a long time, and whether long-term medication was required (Table 1). It was suggested that the older male patients undergoing PCI accounted for 53.41%. Among them, the number of patients with junior high school education or below was the largest, accounting for 59.43%, and there was the largest number of retirees (55.02%). The average monthly household income was less than ¥3,000 (47.79%). Most patients lived in rural areas (63.05%). Most patients had high blood pressure (37.39%) or diabetes mellitus (28.15%). Most of the patients had first PCI and long-term medication (Table 1).

Scores of social support, health literacy and self-care ability in older patients with PCI

The scores of social support, health literacy and self-care ability of older patients with PCI were evaluated and shown in Table 2. The average score of health literacy was 85.96±20.03, including ability of information acquisition (31.94±8.30), ability of communication and interaction (32.08±7.92), ability of improving health (14.79±3.71) and ability of financial support (7.15±1.89). Total score of social support was 25.34±4.93, including subjective support (10.73±2.90), objective support (7.99±1.64) and utilization of support (6.61±2.05). Total score of self-care ability (82.82±27.65) consisted of self-concept (16.71±6.60), self-responsibility (12.31±4.80), self-care skills (21.54±7.13) and health knowledge level (32.25±11.19).

Correlation analysis of social support, health literacy and self-care ability in older patients with PCI

Correlation analysis of social support, health literacy and self-care ability in older patients with PCI was conducted, as shown in Table 3. It was demonstrated that the total score of health literacy in older PCI patients was positively correlated with self-care ability (r=0.142, P=0.02) and social support score (r=0.196, P=0.006). Additionally, the total score of social support was positively correlated with the total score of self-care ability (r=0.179, P=0.009).

The role of social support, health literacy and self-care ability in older patients with PCI

Based on Pearson correlation analysis, we hypothesized that social support had a direct effect on self-care ability, and health literacy was the mediating factor between social support and self-care ability. Therefore, discharge guidance was taken as social support, health literacy as mediating variable, and self-care ability as dependent variable. Maximum likelihood estimation was used to fit the hypothesis model. The model fitting results showed that the mediating effect model had a good degree of fitting (Table 4).

In order to better test the significance of the mediating effect, Bootstrap method with bias correction was used to calculate the confidence interval of the mediating effect, and 5,000 repeated samples were conducted on the data to construct a 95% bias correction confidence interval (CI). The results showed that 95% CI of the total effect, direct effect and indirect effect of the model did not contain 0, and the direct effect was less than the total effect, indicating that rehabilitation health literacy played a partial mediating role between social support and self-care ability. The results of path analysis showed that the direct effect value of patients’ social support on self-care ability was 0.19, the direct effect value of health literacy on self-care ability was 0.06, and the direct effect value of social support on health literacy was 0.25. Therefore, the indirect effect value of social support on self-care ability through health literacy was 0.015. The total effect was 0.205, accounting for 7.32% of the total effect (Figure 3 and Table 5).

Figure 3 Model of the mediating effect of health literacy in social support and self-care ability in older patients after PCI. PCI, percutaneous coronary stent implantation.

Discussion

The HeLMS presents a new approach to assessing health literacy in healthcare settings and is important to patients for seeking, understanding and using health information within the healthcare system (9). In this study, a total of 249 older patients after PCI were investigated, and the total score of health literacy was 85.96±20.03, which was slightly lower than the investigation of Zhang et al. (22). Among them, the score of information acquisition ability is high (31.94±8.30), and the score of financial support ability is low (7.15±1.89), which may be attributed to the following reasons: informatization is the general trend of economic and social development in the world today; information technology makes knowledge more widely disseminated and fully utilized; people have various channels of communication and interaction; and information access is convenient. In this study, 62.65% of the patients came from rural areas, 47.79% of the patients with per capita family income <3,000, and 62.65% of the patients taking medication for a long period of time. Multiple factors have limited the financial support ability of patients.

Orem’s self-care deficit nursing theory considers each individual as a self-care agent with the necessary ability to perform self-care activities individually (24,25). The overall score of self-care ability was at a medium level (82.82±27.65), which was consistent with the research results of Huang et al. (26). The score of health knowledge level in self-care ability was high (32.25±11.19), and the score of self-responsibility was low (12.31±4.80), which may be due to the older age of patients. The long course of CHD itself is often coupled with the long course of hypertension, diabetes and hyperlipidemia, and self-care awareness and behavior of patients will be slack. It is suggested that medical staff should assist patients to strengthen their sense of self-responsibility, provide multidisciplinary teams to give support and help, meet the reasonable needs of patients, reverse or delay the disease process and improve the quality of life of patients after surgery with the joint efforts of patients and their families.

The total score of social support was 25.34±4.93, indicating that the social support of postoperative patients in this study needs to be further improved. Considering that CHD itself is a long-term control process, the social support of patients can be further increased to relieve their physical and mental pressure. In this survey, older patients aged ≥60 years old, due to the physiological restrictions brought by the disease, limited energy, easy to produce fatigue, the maintenance and expansion of social circles will decline. Due to the reasons of residence, some patients are conservative, the communication circle after retirement is relatively limited. They do not want to increase the burden of their children and do not want to seek outside help. So, nursing workers and family members can provide emotional support, material support and information to help them.

The results of this study also showed that the variables of health literacy, self-care ability and social support in older patients after PCI were positively correlated. Specifically, the higher the health literacy level of patients, the higher their self-care ability, which was consistent with the studies of Matsuoka et al. (27), Leung et al. (28), and Liu et al. (29,30). Chen et al. (31) strengthened the health literacy awareness of the older patients in nursing homes through intervention, and found that the self-care ability had been improved. Therefore, nursing workers should strengthen health education for older patients after PCI to improve their health literacy level and enhance their self-care ability. The higher the level of patients’ social support, the higher their self-care ability. A previous study showed that good social support can play a key role in regulating patients’ psychology and behavior (32). Li (33) found that social support has a positive impact on patients’ self-care behavior. Wu et al. (34) provided the evidence that social support can improve patients’ health literacy. It is suggested that medical staff should encourage patients to seek help from the outside world, guide patients’ families to provide emotional and material support, enhance patients’ health literacy, and improve their self-care ability.

The results of structural equation model in this study proved that health literacy plays a partial mediating role between social support and self-care ability in older patients with PCI, which indicates that social support can directly affect self-care ability and indirectly affect self-care ability through health literacy. The social support of older PCI patients includes support from hospitals, families, community health service centers, etc. Patients with high social support can obtain more external resources, and the higher the utilization of their support, especially the stronger the awareness of health care, so as to make up for their defects in self-care ability. A good social network allows patients to have a comprehensive understanding of their condition, which in turn enables them to have a more accurate direction of self-care ability. Studies have shown that health literacy is crucial for individuals to obtain health-related information and take beneficial actions, suggesting that older patients after surgery should actively expand and maintain social network circle, and strengthen health literacy awareness, so as to improve self-care ability and improve postoperative quality of life (35,36). Medical workers should also give patients more confidence and encourage them to communicate effectively with their families for developing patients’ family support and improving the utilization of social support. Finally, it should be noted that health literacy in this study has a partial mediating effect between social support and self-care ability (the mediating effect is 0.015, and the mediating effect value accounts for 7.32% of the total effect), which suggests that there may be other more mediating factors to help improve the self-management level of older patients with PCI. In the future, relevant variables should be included to further supplement the mediating factors of social support and self-care ability.

There are several limitations in this study: First, this is a cross-sectional study with a sample size of 249, and a study with a large sample size is to be investigated in the future. Second, the general demographic data included in this study are limited, and more variables can be included in the future study. Third, other more mediating factors except health literacy are needed to be further investigated in older patients with PCI.

Conclusions

In conclusion, the total scores of health literacy, self-care ability and social support after PCI were 85.96±20.03, 82.82±27.65 and 25.3±4.93, respectively. Health literacy, social support and self-care ability were positively correlated. Social support and health literacy could positively predict self-care ability, and health literacy played a partial mediating role between social support and self-care ability. It is suggested that patients and their families should actively use information technology to improve patients’ health literacy through various channels. Therefore, health literacy becomes a bridge between social support and self-care ability of older patients after PCI.

Acknowledgments

We would like to thank Anna Wei from USA for her help in polishing our paper.

Funding: This study was supported by the Third Batch of Ningxia Young Science and Technology Talents Support Project (No. TJGC2018080) and Key Research and Development Program of Ningxia in 2019 (No. 2019BEG03042).

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://cdt.amegroups.com/article/view/10.21037/cdt-24-50/rc

Data Sharing Statement: Available at https://cdt.amegroups.com/article/view/10.21037/cdt-24-50/dss

Peer Review File: Available at https://cdt.amegroups.com/article/view/10.21037/cdt-24-50/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://cdt.amegroups.com/article/view/10.21037/cdt-24-50/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013), and it was approved by the Ethics Committee of The General Hospital of Ningxia Medical University (No.2018-336). All patients signed informed consent forms before participating in this study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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