Health-related quality of life (HRQOL) in patients with heart failure (HF) is poor, and hospitalization and mortality rates are high.1–5 Symptoms are the primary factors responsible for poor HRQOL and the main antecedents to high hospitalization and mortality rates.1,6 Nonadherence to dietary sodium recommendations explained 22% to 62% of cases of worsening HF symptoms,7,8 and excessive sodium retention explained 55% of hospitalizations for HF decompensation in studies.9 The Heart Failure Society of America and the American Heart Association (AHA) recommend that HF patients restrict dietary sodium intake to 2 to 3 g/d or less than 3 g/d, respectively.10,11
Although patients with HF are advised to follow a low-sodium diet, they commonly do not have the information and skills needed to successfully follow a low-sodium diet.12–15 Therefore, it is necessary to improve dietary sodium adherence effectively to prevent worsening HF symptoms and avoid high rates of hospitalizations and poor HRQOL in patients with HF.
In HF, low-sodium diet education has been a component of many disease management programs.16–18 However, tailored low-sodium diet education based on patients’ actual sodium intake has not been commonly provided.19–21 Some studies show a potential for tailored dietary interventions (TADIs) to reduce sodium intake, although actual dietary sodium adherence rates were not reported. Dietary sodium adherence rate reported in a study was improved after a TADI with social support, but it was still poor (only 46% were adherent).13 In these studies, patients’ perceived barriers to following a low-sodium diet had not been fully analyzed and managed. Social support has been suggested to be helpful to patients as they try to follow a low-sodium diet,14,15 but few programs provide this.13
Development of any successful intervention depends on using a strong conceptual model to support intervention components. In the current study, we have developed a TADI based on a modification of the Social Cognitive Theory and on relevant literature (Figure 1) to provide more effective TADI.22–24 In this theoretical framework, a patient expects better outcomes after following the low-sodium diet, including improved symptom status and HRQOL. To achieve the positive outcomes, the patient sets goals and plans. The patient’s beliefs and values about the benefits of and barriers to the behavior can affect expected outcomes, goals, and action plans.25,26 To perform the action plans effectively, the patient needs behavioral capacity, including the knowledge and skills that lead to confidence.27 After evaluation of behavior and outcomes, the patient continues or modifies his/her behavior. Reinforcement, including psychosocial support and positive outcomes, will help the patient to continue making progress. In the current study, the intervention was tailored based on data analysis of each patient’s diet and beliefs and values, confidence, and behavioral capability at baseline. The tailored intervention was then delivered to improve each of these variables. Education, feedback, counseling, demonstration, practice, and role play were used to enhance patients’ learning and practicing processes. Psychosocial support was used to facilitate patients’ active engagement in following a low-sodium diet.13,14 In this article, we demonstrate the development of the theory-based TADI and present the development processes and the test of feasibility and acceptability in patients with HF.
Study Design, Sample, and Setting
A development team, consisting of 5 experts in HF, nutrition, and clinical trials, developed educational modules for the intervention. The modules were revised based on feedback from the research team, patients with HF, and clinicians. Five symptomatic patients with HF formed the group to pilot test the intervention in their homes and provided data on dietary sodium adherence and factors affecting it (ie, beliefs and values, confidence, and behavioral capability) before and after the intervention and the acceptability of the intervention sessions and educational modules after the intervention. All of the patients were recruited from a hospital in a Midwestern city in the United States. The inclusion criteria were confirmed diagnosis of HF by medical record, New York Heart Association functional class II to IV based on patient interview, and absence of cognitive problems assessed using the Mini-cog test. Patients were excluded if they were referred for heart transplantation, referred for other intervention studies, or had acute myocardial infarction within the previous 3 months.
Institutional review board approval was obtained. Written informed consent was obtained from all participants. Demographic and clinical characteristics were collected at baseline using questionnaires and patient interview. After baseline assessment, intervention sessions were delivered by a registered dietitian and 2 nurses, including the first author. The nurse was trained in the protocol by the dietitian and the first author. Each session was delivered approximately 1 week after the previous session. Acceptability data for sessions 1 through 4 were collected after each session by telephone or face-to-face interview.
Feasibility of Intervention
Refusal, Dropout, and Attendance Rates. Data on refusal rate (number of patients approached and number of patients who refused to participate), dropout rate (number of patients who participated in the intervention sessions and number of patients who dropped out), and attendance rates at the sessions were collected.
Dietary Sodium Adherence. Dietary sodium adherence was defined as consumption of less than 2.5 g of sodium per day based on the recommendation of the Heart Failure Society of America (the midpoint between 2 and 3 g/d)10 and was assessed using a 4-day food diary. The 4-day food diary was chosen because (1) it can provide information that urine sodium cannot provide, such as the sodium content of each meal, intake of specific high-sodium foods, and cooking methods and (2) it is more reliable than the food frequency questionnaire or 24-hour recalls in assessing dietary sodium intake.28,29 To ensure the accuracy of the data, all patients were provided with a digital food scale and instructions on its use. Patients were instructed to record details, amounts, and preparation methods of all foods and beverages consumed. Patients recorded their diet for 3 week days and 1 weekend day to capture variance in food and sodium intake during the week and on weekend days. Food diaries were completed at baseline and follow-up (after intervention) and were reviewed and clarified by a trained research nurse. The diary data were analyzed using Nutrition Data Systems-R software (NCC, University of Minnesota).
Beliefs and Values. Beliefs and values related to following a low-sodium diet were measured at baseline and follow-up (after intervention) by the Beliefs About Dietary Compliance Scale.30,31 This instrument consists of 12 items with 5 response options and assesses individuals’ perceptions of the benefits of and barriers to following a low-sodium diet. Possible scores range from 12 to 60, and higher scores indicate more positive beliefs and fewer barriers. Reliability is satisfactory (Cronbach’s α = .66–.88), and construct validity is acceptable.30,31
Confidence. Confidence related to following a low-sodium diet was measured at baseline and follow-up (after intervention) by the Self-care Confidence in Following a Low-Sodium Diet Scale developed by the authors. This instrument consists of 7 items with 4 response options and assesses confidence in ability to select and prepare low-sodium foods. Possible scores range from 7 to 28, and higher scores indicate greater confidence. Content validity was evaluated and supported by the research team who are experts in HF and nutrition and diet.
Knowledge. Knowledge was measured at baseline and follow-up (after intervention) by the knowledge subscale of the Heart Failure Knowledge and Barriers to Dietary Sodium Scale. This subscale has been used in several HF projects to measure knowledge of HF management and assesses patients’ general knowledge of symptoms and self-care.32 The subscale consists of 13 items with 5 response options. Possible scores range from 13 to 65, and higher scores indicate better knowledge. Cronbach’s α was .70.32 The validity of this instrument was supported by significant relationship between knowledge and self-care behaviors.32
Skills. Skills related to following to a low-sodium diet were measured at baseline and follow-up (after intervention) by the Low-Sodium Diet Skills Scale. It assesses skills in the selection and preparation of low-sodium foods, including selection of low-sodium foods, reading food labels, estimating the sodium content of foods, and substituting low-sodium foods for high-sodium foods. Demonstrations using canned foods are used to assess skills. Possible scores range from 1 to 29, and higher scores indicate better skills. Content validity was evaluated and supported by the research team.
Acceptability of Intervention
The acceptability of each intervention session was assessed using the Acceptability of Intervention Questionnaire developed by the research team. The questionnaire measures usefulness of the sessions and the educational material(s) used, preferences for delivery method, the degree to which patients’ educational needs were met, and the appropriateness of the time spent. Higher scores indicate more acceptability. Content validity was evaluated and supported by experts in the research team.
Data on sociodemographic and clinical characteristics were collected using the Sociodemographic and Clinical Characteristics questionnaires. Data on low-sodium diet recommendations from healthcare providers were collected by patient interview, using questions from the Dietary Sodium Restriction Questionnaire, asking specifically whether they had received dietary recommendations from their healthcare providers and whether they followed them.
Nine educational modules were developed using the following steps: (1) development of the content and materials and (2) revision based on the feedback from the research team, clinician (ie, 1 cardiologist, 1 cardiac nurse, and 1 dietitian outside the research team), and 4 patients with HF (ie, 1 white man, 1 white woman, 1 African American man, and 1 African American woman). The feedback form for the modules consisted of 3 parts: (1) content (ie, appropriateness, coverage, and understanding), (2) format (ie, readability, appropriateness of text size and shape, the amount of information, and acceptability of layout), and (3) an open response item for other content and format issues. On the basis of the feedback of 2 patients, the research team decided to provide study participants with an AHA low-sodium cookbook.
Module 1 provides information about the relationship of diet to symptoms using figures, pictures, and words. Module 2 is a very brief introduction to low- and high-sodium foods using pictures and words. Module 3 shows specific examples of low-, medium-, and high-sodium foods with pictures and words. Module 4 provides feedback to the patient on sodium intake in each meal and high-sodium foods in it, daily sodium intake, and specific substitution methods based on the analysis of the patient’s 4-day food diary. It also shows comparison of dietary sodium intake recommended and the patient’s actual sodium intake. Module 5 explains how to read food labels with canned and/or prepared low- and high-sodium foods using a figure and words. Module 6 provides tips and strategies for selection of low-sodium foods at restaurant and social events using pictures and words. Modules 7 and 8 provide tips for saving time, energy, and money in preparing low-sodium foods using pictures and words. Module 9 provides information about low-sodium seasonings for several categories of foods such as fish, meat, and vegetables using pictures and words.
Development and Delivery of Intervention Sessions
The 5-session TADI was developed and revised by the research team member and delivered to the 5 HF patients to test the feasibility and acceptability. All sessions were delivered to all of the patients (Figure 2 and Table). Sessions 1 and 2 were delivered by the dietitian by telephone and took approximately 30 to 45 minutes. The goal for session 1 was to provide general knowledge on the reasons for following a low-sodium diet and low- and high-sodium foods using modules 1 through 3. During the counseling process, some barriers that each individual had were discussed. The goal for session 2 was to provide situation-specific knowledge about each patient’s eating habits, including sodium intake and high-sodium foods in his/her diet, and strategies on how to substitute low-sodium foods for high-sodium foods using module 4 and the AHA cookbook. Module 4 was developed for each patient by the first author (nurse) and the dietitian based on the patient’s sodium intake and eating habit (eg, high-sodium foods and food components in the diet) and delivered to the patient before session 2. The patient could see the mean amount of sodium eaten per day for the 4 days and the amount of sodium in each meal and also in each high-sodium component in the meal. High-sodium foods or components of high-sodium foods were highlighted with the amount of sodium. In addition, specific suggestions for substituting low-sodium foods or food components for high-sodium foods were presented.
Sessions 3 through 5 were delivered by 2 nurses, including the first author, at the patient’s home and took approximately 30 minutes to 1 hour. The content of sessions 3 through 5 was tailored by the 2 nurses based on the baseline data (eg, beliefs and values, confidence, knowledge, and skills; Figure 2 and Table). The 2 nurses checked each item of the instruments to determine areas in beliefs and values, confidence, knowledge, and skills that needed attention. For example, if a patient already knew how to read food labels but did not know how to select low-sodium foods because of no knowledge about the cut point for low-sodium foods, we delivered information about the cut point and had the patient read the labels of some foods in the house to demonstrate his/her ability to check the sodium amount in the foods. The goals for session 3 were to enhance the general and situation-specific knowledge provided during sessions 1 and 2 and to allow the patient to practice skills in preparing and selecting low-sodium foods at home and outside the home using modules 5 through 9 and the AHA cookbook. The goals for sessions 4 and 5 were to reinforce knowledge obtained during sessions 1 through 3 and provide skills in preparing and selecting low-sodium foods at home and outside the home. Several delivery methods, including education, counseling, feedback, demonstration and practice, role play, and decisional and psychosocial support, were used during all sessions.
Psychosocial support included celebrating patients’ achievements and progress and providing emotional support as necessary. For example, a patient started to use the cookbook and actively collected recipes for low-sodium diet to cook low-sodium foods. The nurse encouraged the patient to set up goals and plans for each week. The nurse celebrated progress with the patient and encouraged continued use of the recipes to cook low-sodium foods. Another patient shared that the patient’s family member cooked low-sodium foods for him more frequently than before because the patient shared what he learned during the sessions. The nurse praised the patient for what he did and celebrated support from the family. The nurse also encouraged the patient to share what he learned in the sessions with others outside the house to receive support from friends and relatives.
In addition, a common activity in all sessions was to set up goals and plans with the patient to perform what was learned in each session and to evaluate achievement of goals, celebrate achievements, and discuss barriers and solutions. Patients were encouraged to share what they learned with their family, friends, and significant others, to practice it and to get more support from them in following a low-sodium diet.
The research team screened 29 patients to determine eligibility for the delivery of the intervention. Fifteen were eligible, 10 were approached, and 6 gave written consent. Reasons for not participating were no interest (2 patients), plans to move to another state (1 patient), and personal life situation (1 patient). One patient had to withdraw before the baseline data collection because of conflicts with her time schedule. All patients who participated in baseline data collection completed all of the sessions.
The 5-session TADI was delivered to 3 female and 2 male patients with HF. Their mean age was 55 years, and mean education level was 12.4 years. All patients were New York Heart Association class III. Patients had HF for between 1.3 and 6.2 years. All reported that they were recommended a low-sodium diet by their healthcare providers and tried to follow it, but only 1 could report the recommended amount of sodium intake (ie, ≤2 g sodium diet). This patient intentionally decided to study a low-sodium diet, knew how to follow it, and had followed it. The other patients reported the recommendations as “only low-sodium diet,” “watch your salt,” or “stay away from salt.”
Mean (SD) dietary sodium intake decreased from 2.38 (1.26) g/d at baseline to 1.30 (0.78) g/d at follow-up. At baseline, 3 of 5 patients ingested more than 2.5 g of sodium daily, but all the patients reduced their intake to less than 2.5 g/d at follow-up. All data on beliefs and values, confidence, and behavioral capacities were collected from all participants without difficulty. Scores on beliefs and values, confidence, and behavioral capability were higher at follow-up than at baseline, but significance could not be tested because of the small sample size (beliefs and value scores increased from 46 to 51 of 60; confidence from 20 to 24 of 28; knowledge from 54 to 57 of 65; and skills from 15 to 28 of 29). Most patients perceived that there were benefits to following a low-sodium diet at baseline and perceived them more positively at follow-up. Patients reported at both baseline and follow-up that a low-sodium diet made it difficult to go to restaurants. Patients were less confident in estimating sodium amount at baseline, and 3 patients were extremely confident at follow-up. Patients’ skills scores showed the greatest improvements between baseline and follow-up in differentiation of high- and low-sodium foods, selection of low-sodium foods outside the home, and estimation of sodium amount in their diet.
During sessions 2 through 5, patients shared what they or their family did related to following the low-sodium diet the past week. For example, 1 patient was excited to show the nurse low-sodium foods that she bought while grocery shopping. Another patient showed the nurse low-sodium food that his niece brought for him because he shared information about a low-sodium diet with her. One patient reported that the family members showed interest in a low-sodium diet and provided low-sodium foods more frequently.
For sessions 1 through 4, acceptability data from the patients were collected after each session. The mean scores for sessions 1, 2, 3, and 4 were 98%, 97%, 100%, and 100% of 100%, respectively. The reasons for the lack of 100% acceptability rating for each session were explored. In session 1, 2 patients reported that they knew some of the content, 1 patient wanted to know more about fruits and vegetables, and 1 patient could not pick any specific thing, but felt unable to give a perfect score because he felt that there is always room for improvement. In session 2, 2 patients wanted more situation-specific information about the low-sodium diet, including modifying strategies, and 1 patient wanted a face-to-face delivery method.
This study demonstrated the feasibility and acceptability of the TADI program and the potential of this program for improving dietary sodium adherence. Patients evaluated the modules and intervention sessions positively and showed a potential for improving dietary sodium adherence.
Several strategies to enhance patients’ practical learning were used in the current study. For example, patients received information on the content of each meal they ate, sodium intake in a meal with high-sodium foods or food components, average daily sodium intake compared with the recommended sodium intake for patients with HF, and methods for substituting high- with low-sodium foods. This information was designed to help the patients estimate sodium amount in the foods they regularly ate and substitute low-sodium items rather than eliminating their usual foods entirely. This intervention used repeated demonstration, practice, and role play to enhance patients’ confidence and behavioral capability. The repeated sessions promoted gradual change that is more amenable to patients and does not force radical changes that patients are likely to ignore.
The intervention provided patients psychosocial support to enhance their learning and facilitate their active engagement in following a low-sodium diet. Psychosocial support has been reported as a factor affecting dietary sodium adherence.13,14 The nurse established goals and made plans with the patients that took into account their eating habits, confidence, and behavioral capability. The nurse celebrated the achievement of goals with patients and discussed barriers with them, providing practical and emotional support to overcome barriers. In addition, the nurse encouraged patients to share their knowledge and skills related to a low-sodium diet with their significant others. As a result, several patients reported that they had more support from their families in following a low-sodium diet.
The current study showed a potential for improving dietary sodium adherence and factors affecting it. In 1 dietary education and counseling study,13 dietary sodium decreased in an education and counseling only group from 2.07 to 1.75 g/d and in an education and counseling combined with family support group from 2.03 to 1.78 g/d. In the current study, average sodium decreased from 2.38 to 1.30 g/d. However, the sample size in the current study was very small. Thus, further studies with appropriate sample size will be helpful to test the effects of TADI on reduction in dietary sodium intake.
The findings of this study provide some explanation for how this intervention improved dietary sodium adherence. Knowledge alone is not enough to improve self-care.33–35 Skills and confidence have been suggested to impact self-care.24 Skills related to preparing and selecting low-sodium foods were poor at baseline compared with other factors affecting dietary adherence and showed the greatest improvement after the intervention in this study. However, skills and situation-specific knowledge about dietary sodium intake have been rarely a focus of dietary interventions in HF. In this study, all patients received dietary recommendations from their healthcare providers and had some general knowledge, confidence, and beliefs and values about HF and general disease management. However, they did not have appropriate levels of situation-specific knowledge and skills to make practical changes in diet. Patients in this study did not know how much sodium they ate on a daily basis. They were unable to identify high-sodium foods in their diet. Thus, they could not know whether they needed to change their diet, what needed to be changed, or how it could be changed. Therefore, situation-specific knowledge and skills should be provided to improve dietary sodium adherence.
The findings of this study support the feasibility and acceptability of a TADI combined with psychosocial support to improve dietary sodium adherence and factors affecting it. A randomized controlled trial with a larger, more diverse sample is planned to test the effects of the intervention on outcomes.
What’s New and Important
- This study shows the potential of a theory-based TADI on dietary sodium adherence and factors affecting it.
- This study shows possible barriers in following a low-sodium diet: lack of situation-specific knowledge and skills.
- This study shows the development and test processes of a theory-based new dietary intervention.
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Keywords:Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved
dietary intervention; heart failure; self-care; sodium