Effects of a Health Literacy Education Program on Mental Health and Renal Function in Patients With Chronic Kidney Disease: A Randomized Controlled Trial

ABSTRACT Background Chronic kidney disease (CKD) refers to permanent damage to the kidneys that occurs gradually over time. Further progression may be preventable depending on its stage. Purpose This study was developed to evaluate the effect of a health literacy education program (HLEP) on mental health and renal functioning in patients with CKD. Methods A single-blind, randomized controlled trial study was conducted. Data were collected from March 25 to December 18, 2021. Participants were randomly assigned to either the experimental group (n = 42), which received multidisciplinary care and HLEP, or the control group (n = 42), which received multidisciplinary care only. Data were collected at baseline (T1), Month 3 (T2), and Month 6 (T3), and the data included patient characteristics, estimated glomerular filtration rate, and responses to the Mandarin Multidimensional Health Literacy Questionnaire and Beck Depression Inventory. Results After 6 months of the HLEP intervention, the results of generalized estimating equations analysis showed that, compared with the control group, the experimental group had significantly higher health literacy at Month 3 (β = −3.37, 95% CI [−5.68, −1.06]), significantly improved depression at Month 3 (β = −2.24, 95% CI [−4.11, −0.37]) and Month 6 (β = −4.36, 95% CI [−6.60, −2.12]), and a significantly higher estimated glomerular filtration rate at Month 6 (β = 5.87, 95% CI [1.35, 10.38]). Conclusions/Implications for Practice The findings of this study may provide a reference for healthcare providers to educate patients with Stage 3–4 CKD using the HLEP. Positive effects on health literacy, depression, and renal function in patients with Stage 3–4 CKD were observed in the short term. Findings from this study may facilitate the implementation of multidisciplinary and nurse-led strategies in primary care to reinforce patients' health literacy, self-care ability, and adjustment to CKD as well as delay disease progression.


Introduction
Chronic kidney disease (CKD) is a global public health issue that affects many people around the world.Of the estimated 14.4% of adults in the United States who have CKD, up to 90% are unaware of their disease (U.S. Renal Data System, 2021).A study on 3,713 patients with Stage 3-4 CKD categorized the sample into four risk levels for renal failure within 5 years: minimum risk (< 2%), low risk (2%-4%), moderate risk (5%-14%), and high risk (≥ 15%).The study concluded that up to 51% of patients in the moderate-and high-risk populations were unaware of their CKD.Patients have a much lower awareness of CKD than of diabetes and hypertension (Chu et al., 2020).However, the onset and progression of a chronic disease tend to be slow, and patients with CKD often have one or more concurrent chronic diseases (Elliott et al., 2020).The progression of chronic disease also affects the mental health of patients.Studies have shown that up to 75.5% of patients with CKD experience depression, which in turn compromises their quality of life (QOL; Kunwar et al., 2020).This emphasizes the importance of aggressive screening and early intervention.
Conclusions/Implications for Practice: The findings of this study may provide a reference for healthcare providers to educate patients with Stage 3-4 CKD using the HLEP.Positive effects on health literacy, depression, and renal function in patients with Stage 3-4 CKD were observed in the short term.Findings from this study may facilitate the implementation of multidisciplinary and nurse-led strategies in primary care to reinforce patients' health literacy, self-care ability, and adjustment to CKD as well as delay disease progression.
transplantation, is required to avoid kidney failure (National Kidney Foundation, 2022).Therefore, delaying CKD progression is the key focus of medical care.In Taiwan, since the enactment of the National Health Insurance's Healthcare and Health Education for Pre-End Stage Renal Disease Patients Program in 2003, the high-risk population with CKD (patients in Stages 3b-5) has been subject to case management and receives care from a professional medical team responsible for assessing each patient's self-care and self-management abilities.Furthermore, this team follows up on patient health status to help maintain residual renal function.As part of the program, the CKD Clinical Practice Guidance recommends initiation of a low-protein diet (0.6-0.8 g/kg a day) and ketogenic amino acid treatment for patients with Stage 3 CKD to reduce kidney damage caused by nitrogenous wastes and delay dialysis or death (Xu, 2015).
Health literacy is a relatively new field of research in the area of medicine and health.Different age groups require different health literacy programs to empower them to implement beneficial health behaviors (Quaglio et al., 2017).A systematic review by Sørensen et al. (2012) defined health literacy as the "knowledge, motivation, and competencies of accessing, understanding, appraising, and using health-related information within the healthcare, disease prevention and health promotion setting in daily life to make judgment and decisions in order to maintain or improve the overall QOL."Therefore, health literacy influences self-care efficacy and disease prognosis.Lack of health literacy has been reported in 17.7% of patients with Stage 1-5 CKD (Schrauben et al., 2020), and low or absent health literacy has been reported in 22.5% of patients with Stage 3-4 CKD (Hanpaiboon & Pratoomsoot, 2019).Wei et al. (2017) has evaluated the validity of the Mandarin Multidimensional Health Literacy Questionnaire (MMHLQ) on a sample of 2,394 adults in Taiwan, finding the highest score in the domain of "understanding health information," followed by "accessing health information," "communication and interaction," "applying health information," and "appraising health information."Factors that affect health literacy include age, gender, educational level, marital status, spouse cohabitation status, family income, CKD stage, duration of CKD, and number of comorbidities (Y.-C.Chen et al., 2018;Hanpaiboon & Pratoomsoot, 2019;Wong et al., 2018).Patients with higher health literacy show better self-care behaviors (Schrauben et al., 2020).
Patients with CKD tend to experience depression because they are forced to attend numerous hospital visits and face complex treatment plans, drug side effects, dietary restrictions, and uncontrollable clinical symptoms as their disease progresses (S.F. V. Wu et al., 2018).The prevalence of depression is related to CKD stage.A meta-analysis of 22 studies that investigated the correlation between depression and death in patients with CKD reported an average depression prevalence of 27.4% in predialysis patients with CKD (Palmer et al., 2013).Patients with CKD experiencing depression exhibit poor compliance to drug treatment and poor QOL, resulting in increased utilization of medical resources and higher rates of morbidity and mortality (Palmer et al., 2013).
A study conducted by S. F. V. Wu et al. (2018) applied an innovative health education program promoting self-management in a sample of patients with Stage 3b-5 CKD.The program delivered one 100-minute session per week for 4 weeks, and the participants were followed up for 3 months.Outcomes included significantly improved blood urea, nitrogen, and creatinine; reduced depression; and higher self-efficiency and self-management.However, the intervention had no effect on eGFR.Wang et al. (2018) conducted a cross-sectional study to compare the effect of participation in a comprehensive healthcare program on self-care behaviors and kidney function in patients with CKD.The results revealed a slower rate of deterioration in kidney function and better self-management behaviors in patients participating in the healthcare program.Machida et al. (2019) studied the effects of a 1-week inpatient education program on kidney function in patients with Stage 3-5 CKD.The patients were followed from 6 months before hospitalization to 24 months after discharge.Implementation of the program delayed kidney function deterioration during the 2-year observation period, especially in patients with low proteinuria (urinary protein < 0.5 g/gCr).Thus, the authors recommended the program be initiated in patients with low proteinuria.A randomized clinical trial conducted by Lin et al. (2021) investigated patients with Stage 1-3a CKD, with the study group receiving routine care and health coaching for 6 weeks in addition to 12 months of postintervention followup.The findings indicate health coaching improves QOL, self-management, patient activation, and self-efficiency.
On the basis of the evidence in the literature, health education programs are beneficial to patients with CKD.Health literacy can influence self-care behaviors and renal function in these patients.However, there is a lack of rigorous research on the impact of health literacy on the psychology of patients with CKD.Therefore, the aim of this study was to investigate patients with Stage 3-4 CKD (the largest group in Taiwan's Pre-End Stage Renal Disease Patients Program), develop a health literacy education program (HLEP), and evaluate the effect of this program on participants' mental health and renal function.This study addressed the following research hypotheses: 1. Patients with CKD who participate in the HLEP will have increased health literacy compared their nonparticipant peers.2. Patients with CKD who participate in the HLEP will have improved depression compared their nonparticipant peers.3. Patients with CKD who participate in the HLEP will have improved renal function compared their nonparticipant peers.

Design
The study design was a single-center, two-group, single-blinded, randomized controlled trial with a repeated-measures design.
The participants were randomized into either the HLEP with multidisciplinary care (experimental) group (EG) or the multidisciplinary care (control) group (CG).Block randomization with 1:1 allocation was conducted using a computer-generated sequence and was performed by one of the authors not involved in screening, patient recruitment, clinical care, or data collection using a random number generator.Sequentially numbered, opaque, sealed envelopes were used to conceal the sequence until the interventions were assigned at an outpatient nephrology clinic.Patients were followed for 6 months.Data were collected before health education (T1) and at 3 months (T2) and 6 months (T3) after completion of the HLEP (Figure 1).

Setting
The participants in this study were conveniently sampled from the nephrology outpatient clinic of a 988-bed regional educational hospital in northern Taiwan.

Participants
Patients who met the selection criteria were recruited.The inclusion criteria were patients aged ≥ 20 years who were able to communicate in Mandarin or Taiwanese, were diagnosed by a nephrologist with Stage 3 or 4 CKD, and had received less than 1 year of comprehensive care.The exclusion criteria included having a cognitive disorder or mental illness (severe depression, schizophrenia), being on routine hemodialysis, or current hospitalization.

Sample Size
Following Wang et al. (2018), minimal sample size was calculated using G*Power V3.1 statistical software with eGFR as the primary efficacy variable (EG: eGFR = 0.072 ± 8.212, n = 118; CG: eGFR = −2.978± 8.680, n = 117).The effect size was estimated as 0.36, α was set at .05, and power was set at 0.95.The participants were divided into two groups with three measurements each.The minimum sample size was calculated as 70.Assuming a follow-up loss of 20%, the final sample size was set as 84 (42 per group).

Experimental Intervention and the Control Group
The main components of the HLEP are shown in Table 1.
The HLEP included a self-management health education manual and a dietary health education video designed for patients with Stage 3-4 CKD.The health education manual was developed by the researchers based on the Health Literacy Concept and Material Preparation Guide (National Health Insurance Administration, Ministry of Health and Welfare, Taiwan, ROC, 2020) and frequently asked questions from patients and family members.The preliminary review focused on the content and format of the draft, with subsequent revisions made based on comments (Devellis, 2016).Five experts were invited to assess the content validity, with the content validity index assessed in terms of "appropriateness," "accuracy," and "readability" as .98,.88,and .95,respectively, on a 5-point Likert scale, with an overall content validity index of .93.The content of the health education manual was edited based on the experts' comments to create the final version.In the interests of portability, the size of the health education manual was designed as 145 mm in length and 210 mm in width with 15 pages.As most of the participants in this study were older adults, the dietary principles were presented in video format.To maximize learning outcomes, an attending physician from the department of nephrology and one of the researchers personally introduced the dietary principles for patients with Stage 3-4 CKD based on the health education manual.Media professionals were hired to produce the video and sound recordings using PhotoImpact and Adobe Audition for conversion to MP3.The video was designed with a minimum of text and used simple words, pictures, cartoon figures, large fonts, and interactive images.
In the EG, members received one-on-one health education from a study team member with 6 years of experience in kidney disease nursing.The HLEP was delivered using a health education manual in the nephrology outpatient health education classroom.After each session, the participants and their families watched a health education video and were encouraged to ask questions until they fully understood the concepts.In addition, EG participants were taught how to access the videos via their smartphones on YouTube or by scanning a QR code on the cover of the health education manual.
CG participants received routine one-on-one health education from a case manager at the participating hospital who explained the blood analysis results and precautions and distributed an A4-sized health education leaflet.

Data Collection
Data for this study were collected from March 25 to December 18, 2021.The data were collected at three time points: before HLEP implementation (T1) and at 3 months (T2) and 6 months (T3) after HLEP.For participants who were illiterate or had difficulty reading and thus not able to complete the questionnaire independently, a designated staff member explained the questionnaire and assisted them to complete it based on their answers.EG participants received

The Journal of Nursing Research
Hsiao-Ling HUANG et al.
multidisciplinary care, participated in the HLEP, and conducted monthly phone discussions with the researcher about the program's content on the first Monday of each month.CG participants received multidisciplinary care, and their data were collected at the same time points as EG participants.

Ethical Considerations
This study was approved by the research ethics committee of National Taiwan University Hospital Hsinchu Branch (Approval No. 91T-27-0026) before initiation.The investigator explained the study purpose and procedure to the participants before they signed informed consent.The participants were informed they were free to withdraw at any time during the study and that their withdrawal would not affect their treatment or cause any negative impact.The study data were coded and analyzed anonymously.

Demographic and disease characteristics
The patient characteristics considered in this study included age, gender, educational level, marital status, monthly income, CKD stage, chronic disease history, and duration of treatment in the nephrology department.

Mandarin Multidimensional Health Literacy Questionnaire
The MMHLQ developed specifically for adults in Taiwan by Wei et al. (2017) was used in this study.The 20 items of the MMHLQ assess health information, health information comprehension, health information appraisal, health information application, communication, and interaction using a 4-point scale: 1 = very difficult, 2 = difficult, 3 = easy, and 4 = very easy.Total and subscale scores are converted to a 0-50 range using the equation (Mean − 1) Â (50/3), with 0-25 indicating insufficient, 25-33 indicating limited, 33-42 indicating sufficient, and 42-50 indicating excellent level of health literacy.Higher scores on the MMHLQ indicate better health literacy.The internal consistency reliability analysis revealed good internal consistency (Wei et al., 2017), with a Cronbach's alpha of .92 in this study.

Beck Depression Inventory
The 21-item Beck Depression Inventory-II (BDI-II) Chinese version was used in this study to measure depression.Items are scored on a 4-point Likert scale, with 0 = no, 1 = mild, 2 = moderate, and 3 = severe symptoms.The participant chooses the statement in each item that best describes how they felt over the past 2 weeks (including the day of the examination).The total score ranges between 0 and 63, with 0-13 indicating normal emotion, 14-19 indicating mild depression, 20-28 indicating moderate depression, and 29-63 indicating severe depression.The BDI-II is aligned with the diagnostic principles of depression in the Diagnostic and Statistical Manual Disorders, Fourth Edition and thus may be used to determine depression status.The BDI-II has excellent validity (H.Y. Chen, 2000), and the internal consistency Cronbach's α value in this study was .82.

Renal function
In this study, eGFR was used to monitor kidney function.Data were collected from medical records, and eGFR was calculated using the Modification of Diet in Renal Disease simplified equation developed by the Modification of Diet in Renal Disease Study Group (Levey et al., 2007).The participating hospital scheduled visits for the patients every 3 months, and one blood sample was collected based on the guidelines of the comprehensive care program for kidney disease.Blood samples were collected from the patient during the week before the scheduled visit date.

Data Analysis
IBM SPSS Statistics for Windows 20.0 (IBM Inc., Armonk, NY, USA) was used for data archiving and statistical analysis, with results presented as frequency, percentage, mean, and standard deviation.The demographic and disease characteristics were compared between the groups using the w 2 test, independent samples t test, and paired samples t test.The outcome variables, including health literacy, depression, and eGFR, were compared between the two groups using a generalized estimating equation with repeated measures.

Results
Eighty-four participants completed the study (0% attrition), with 42 each in the EG and CG.Age ranged from 30 to 87 years and averaged 65.39 (SD = 11.39)years.No significant differences between the two groups were found in terms of demographic and disease characteristics (Table 2).
As shown in Table 3, no significant differences between the two groups were found in terms of health literacy, depression, or eGFR before the HLEP intervention.The average MMHLQ score of the participants before health education was categorized as "limited."The highest scores for both groups were reported in the domain of "understanding health information," followed by "communication and interaction," "applying health information," "appraising health information," and "accessing health information."In terms of depression, only 16 (19.1%)participants reported depression before the intervention, including 15 (17.9%) with mild and one (1.2%) with severe depression.There were 31, 10, 0, and 1 participant in the EG and 37, 5, 0, and 0 participants in the CG with normal, mild, moderate, and severe depression, respectively, with no significant between-group difference in depression noted (w 2 = 10.129,p = .928).The MMHLQ, depression, and eGFR scores over time for the two groups are presented in Figure 2, and a summary of the GEE results for MMHLQ, depression, and eGFR is shown in Table 4.A model with an exchangeable correlation matrix and model-based estimates of variance was used.
After adjusting for age and gender, relationships between health literacy and, respectively, time, group, and Time Â Group interaction were explored.The model showed the time effect as more significant for T2 and T3 compared with T1.Trend differences (interactions between time and group) revealed significant differences in health literacy at T2,

Discussion
The participant characteristics align with the general population with Stage 3-4 CKD in Taiwan, with a predominantly male (79.8%) and Stage 3 CKD (66.6%) study group, averaging 65.39 years old (SD = 11.39).According to statistics from the 2016 to 2018 kidney disease in Taiwan annual report, CKD is most prevalent in older adult men, with Stage 3 being the most commonly observed stage (National Health Research Institutes & Taiwan Social of Nephrology, 2020).The top three concomitant chronic diseases reported by the participants were hypertension (79.8%), diabetes (53.0%), and gout (35.7%).The largest percentage (40.5%)had two concomitant diseases, 32.1% had three, and 25% had one.These findings are consistent with previous statistical data on patients with CKD, who frequently report one to two concomitant chronic diseases (Elliott et al., 2020).According to the 2020 kidney disease in Taiwan annual report, the top three concomitant diseases reported in the previous year by new dialysis patients were hypertension, heart disease, and diabetes (National Health Research Institutes & Taiwan Social of Nephrology, 2020).These data were based on the kidney biopsy results presented in the kidney disease in Taiwan annual report, in which nephrotic syndrome and proteinuria of unknown cause accounted for 46.4% of the cases, and 20.2% of acute renal injury was caused by the improper use of nonsteroidal anti-inflammatory drugs.Nonsteroidal anti-inflammatory drugs are the most used drugs by patients with gout (National Health Research Institutes & Taiwan Social of Nephrology, 2020).
The health literacy of the participants before the intervention was "limited," which is similar to the result reported by the National Health Research Forum (2020).Up to 50% of older patients lack sufficient health information for health decision making because of an insufficient level of health literacy.The MMHLQ used in this study returned the highest score for both groups in the "understanding health information" domain, followed by "appraising health information" and "accessing health information."Only the "understanding health information" domain achieved a "sufficient" level, whereas the other domains were "limited."This finding differs from the results of several previous studies (Wei et al., 2017;C. L. Wu et al., 2020).Wei et al. reported the highest mean MMHLQ score in the "understanding health information" domain, followed by the "accessing health information," "communication and interaction," "applying health information," and "appraising health information" domains.C. L. Wu et al., investigating the health literacy of 458 patients from eight patient support groups, reported the highest mean MMHLQ score in the "understanding health information" domain, followed by the "communication and interaction," "accessing health information," "applying health information," "understanding health information," and "appraising health information" domains.The difference in findings may be attributed to differences in study purposes and samples.Nevertheless, health education materials and approaches for patients with CKD should emphasize these four domains of MMHLQ, with particular focus given to the health information domain.
Health literacy improved significantly in the EG between T1 and T2 and remained relatively unchanged between T2 and T3.One possible reason for this outcome is that 65.5% of the participants had an educational level below the college level and were predominantly older individuals who likely required more time to learn.The level of health literacy before health education was "limited" for both groups and had improved to "sufficient" for the EG at T2 and T3 and to "sufficient" for the CG only at T3.The EG showed a more significant growth trend in health literacy compared with the CG, indicating that an even longer follow-up period is necessary to determine the long-term effects of the intervention.
Before the intervention, only 19.1% of the participants reported experiencing depression, with 17.9% having mild depression and 1.2% having severe depression.This differs from Loosman et al. (2015), which found a 34% prevalence of depression among patients with Stage 3b-4 CKD and a mean eGFR of 20.4 (SD = 6.3) ml/min per 1.73 m 2 at baseline.Their findings suggest that the proportion of patients with depression rises as renal function declines.The prevalence of depression among the participants in this study was relatively low, which may be explained by most participants (65.5%) being in Stage 3 CKD and the overall mean eGFR at baseline being 35.96 ± 11.53 ml/min per 1.73 m 2 , indicating better renal function.At T2 and T3, depression had improved significantly in the EG, which is similar to S. F. V. Wu et al. (2018), who also employed an innovative self-management program on a group of patients with Stage 3b-5 CKD.In their study, depression decreased significantly at 3 months after the intervention, which included individual health education every 3 months during the study period and a visit and phone interview on the first week of each month.Regular contact and establishing excellent rapport helped make subjects feel concern for their physical and mental issues, which further improved their depression.
The participants in this study included 65.5% in Stage 3 and 34.5% in Stage 4 CKD.According to the CKD prevalence in adults in a cohort study conducted from 2015 to 2018, 5.8% patients had Stage 3, 0.4% had Stage 4, and 0.1% had Stage 5 CKD, with Stage 3 comprising the highest proportion (U.S. Renal Data System, 2021).In our study, after the intervention, eGFR increased consistently with time in the EG and decreased significantly with time in the CG until T3, at which time the eGFR was significantly higher in the EG than the CG.This result supports the recommendations of S. F. V. Wu et al. (2018).In their study, the EG was enrolled in an innovative self-care program, and no significant improvement was observed in eGFR after 3 months of follow-up.The authors suggested that the follow-up period should be extended to 6-12 months to better detect the effect.Wang et al. (2018) reported similar results in their study investigating patients with Stage 1-5 CKD.In patients receiving more than 1 year of comprehensive CKD care, the healthcare program group attained a 2.83-fold higher likelihood of experiencing a slower deterioration of kidney function than the non-healthcare program group.eGFR increased by 3.87 ml/min per 1.73 m 2 on average in the EG and decreased by 1.81 ml/min per 1.73 m 2 on average in the CG at 6 months after the intervention.On the basis of their findings, HLEP was deployed in this study to enhance kidney function.

Limitations of the Study
This study was affected by several limitations.First, recruitment in this study was limited to patients with Stage 3-4 CKD at a single district teaching hospital in northern Taiwan.Although their characteristics were similar to the general population of patients with Stage 3-4 CKD in Taiwan, the results may not be generalizable to patients with CKD nationwide.Future studies should include larger sample sizes from multiple hospitals with different stages of CKD.Second, this study followed the patients for a postintervention period of 6 months only, which may not capture the long-term effects on health literacy of the HLEP program.Therefore, the study period should be extended in future studies to evaluate long-term efficacy.Third, the participants in this study were patients who had participated in a multidisciplinary care program for less than a year.Future studies should include patients with no prior multidisciplinary care program experience to determine the effectiveness of the self-management health education program on this patient group.Finally, the study was conducted in a single clinic, and the intervention and data collection were performed by the same researcher, which may have introduced a Hawthorne effect.To minimize the potential for this bias, future studies should recruit from multiple clinics and use different researchers for intervention and data collection tasks.

Conclusions and Implications for Practice
The results of this study indicate the developed HLEP program significantly and positively affects the health literacy of patients with CKD within 3 months of program completion.Moreover, at 6 months posttest, the severity of depression decreased and kidney function improved significantly in the EG.Furthermore, the mean eGFR increased in the EG by 3.87 ml/min per 1.73 m 2 at 6 months posttest, whereas eGFR decreased by 1.81 ml/min per 1.73 m 2 in the CG.These findings suggest the HLEP may be an effective tool for improving health literacy and clinical outcomes in patients with CKD.This study may serve as a reference for nephrology case managers responsible for educating patients with Stage 3-4 CKD using the HLEP.In practice, the HLEP developed in this study may be accessed by patients at home on their computer/cellphone or via the provided QR code.The provided health education manual is small and easy to carry and may be used as a reference when dining out.Health education manuals are a more convenient format than traditional health education leaflets.A good health education tool can enhance case manager performance, increase patient confidence in controlling their kidney disease, and delay disease progression.Therefore, this tool is worth considering in practice.Overall, the results of this study suggest providing tailored health education to patients with Stage 3-4 CKD using the HLEP can improve health literacy and clinical outcomes and benefit both patients and healthcare providers.

Figure 1
Figure 1Research Design Flowchart

Figure 2
Figure 2 Group Comparisons of Outcomes at Baseline, Month 3, and Month 6

Table 1
Main Contents of the Health Literacy Education Program Note.CKD = chronic kidney disease.

Table 2
Homogeneity Test of Demographic and Clinical Characteristics (N = 84) Note.EG = experimental group; CG = control group; CKD = chronic kidney disease.a Fisher's exact test.

Table 4
Results of Generalized EstimatingEquations for MMHLQ, Depression, and eGFR Score (N = 84) Note.Adjusted: age and gender.MMHLQ = Mandarin Multidimensional Health Literacy Questionnaire; eGFR = estimated glomerular filtration rate.a Reference group: control group.b Reference group: baseline (T1).c Reference group: Control Group Â Baseline.