This study is a parallel, single-blind, randomized controlled trial. The study protocol has been reviewed and approved (No. 9411449005) by the Institutional Review Board (IRB) at Tehran University of Medical Sciences (TUMS, Tehran, Iran). The study protocol is based on the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 guideline [34].

This study will be conducted at the Tehran Heart Center (THC) HF clinic affiliated with TUMS. THC is one of the best equipped diagnostic and therapeutic cardiology centers with full-time specialists and well-trained nursing staff in the region and is a referral center for cardiology in Iran with more than 1,300,000 outpatient visits, and 280,000 patient hospitalizations from 2001 to the end of 2017 [35].

The research nurse (author MN) will screen the medical records of adult patients (≥18 years of age) of both genders for the following inclusion criteria in the HF clinic. The eligibility of each participant will be confirmed by the HF specialist (see Textbox 1).

In this study, the intervention is an integrated package consisting of 3 components: (1) HF self-care education, (2) regular home self-monitoring of weight and SOB, and (3) scheduled call follow-ups.

The first component of the package includes HF self-care education that will be delivered in the HF clinic of the THC according to the Australian Heart Foundation educational booklet entitled “living well with chronic HF” [38]. Individual education will be provided by the research nurse (MN) according to the participants understanding and literacy for a 40-minute face-to-face session between 8 am to 1 pm. A Farsi version of the booklet will be given to each participant. Also, during the educational session, the instructor and the participant will review the booklet content together, and the instructor will answer any questions. The booklet contains information on disease definition, diagnosis, symptoms, and ways to manage them, lifestyle issues, medicines, and other treatments. In order to obtain permission to translate the booklet to Farsi language for local use in Iran, one of the authors (MN) contacted the Australian Heart Foundation on April 5, 2016. After obtaining permission, it was translated to the Farsi language by an individual who was also proficient in the English language and knowledge of cardiovascular terminologies. Two nursing faculty members and 2 cardiology faculty members affiliated with TUMS approved the Farsi version of the booklet.

The second component of the package includes regular home self-monitoring of weight and SOB and recording them in the appropriate 3-color daily diaries for 3 months. Since the graphical display of values help patients to recognize their symptoms and contact their health care provider [23], we created a paper-based weight and SOB self-monitoring daily diary color-coded system that was analogous to TLS.

Based on previous studies, a graphical representation of health-related information is the preferred method for patients compared to numerical/tabular displays [39,40] for communicating medical risk information [41]. This approach results in better participant comprehension. The patient pays attention and extracts more information with less effort [31]. Thus, both research diaries have been designed in 3 colors and categorize the participants’ condition into 3 color-coded zones: green (excellent), yellow (use caution), and red (warning). The green, yellow, and red color-coded zones have been defined based on a combination of American Heart Association self-check plan for HF management [42] and the HF self-monitoring toolkit [43]. The colored diary will display recorded data in both graphical and tabular format. It is expected that this will result in a better participant understanding of their condition.

In the HF clinic, participants will be instructed by the research nurse on the daily measurement of weight and SOB and recording them in the daily diary during a 20-minute individual session between 8 am and 1 pm. The weight diary is a 7-page colored diary with instruction on the first page followed by 6 blank pages to record daily weight for 15 continuous days on each page.

At the time of referral to the THC, the HF specialist will measure the weight of eligible participants by analog weight scale (RASA scale, model 230, Iran). Then, 2 upper control limits will be determined for participants by the research nurse to identify 1 and 2.5 kg greater than the baseline weight that is considered as yellow and red zones in the weight diary, respectively [23] (see Figure 1). During instruction, the participants will be asked to weigh themselves daily after going to the toilet, before breakfast, with the same type of clothing, at the same time [38] and record it regularly in the weight diary for 3 months. If participants miss a weight measurement for any reason, they will be asked to record the reason for the missed date. They also will be instructed to contact the research nurse in case of sudden weight gain of 1 kg in one day (yellow zone) and 2.5 kg in one week (red zone) [44].

The SOB diary is a 4-page colored diary that includes instructions on the first page and 3 blank pages to record the difficulty of breathing for 30 continuous days on each page. The participants will be instructed on how to use the SOB colored diary, and how to rate the difficulty of breathing for the entire day after taking evening medications and at the end of each day for 3 months [23]. They will also be instructed to record the reason for any missed measuring dates.

The SOB rating scale was designed based on 0 to 10 pain assessment visual analog scale. In this scale, scores are categorized as follows: none (0), mild (1-3), moderate (4-6), and severe (7-10) [45] that have been marked by green, yellow, and red colors, respectively. Green, yellow, and red color zones will be explained to participants as no new or worsening (none-mild SOB), worsening with activity or at night when lying down (moderate SOB), and struggling to breath or at rest or while sitting (severe SOB), respectively [42] (see Figure 2). Participants will be instructed to contact the research nurse if they reach the yellow color zone to increase the diuretic dosage and contact with the emergency medical services in the red color zone [38].

The third component of the package includes scheduled follow-up phone calls (days 1, 3, and 7 after referral to the HF clinic and every week after that) for 3 months [21]. The research nurse will give participants a list of call dates and will call each subject in the evenings between 6 pm and 9 pm. Each follow-up phone call will last 5-15 minutes [21] and is designed to review the content of the instructional session, encourage participants to continue weight and SOB self-monitoring, and record them in the daily diaries. Also, the research nurse will ask the participants about the color zone during the previous week and will recommend the appropriate action (see Figure 3). Also, we predict that during the call follow-ups, participants in the intervention group will report another symptom that may be due to a side effect of the medications or the disease. The research nurse will be able to provide the appropriate recommendation for each symptom reported in the intervention group during these (see Figure 4).

At the end of the one-hour instructional session in the HF clinic, a plastic folder containing the instructional booklet, weight, and SOB colored diaries, pen, pencil, eraser, and a pencil sharpener will be delivered to each subject in the intervention group. They will be asked to keep diaries clean and deliver them to the research nurse at the end of the study.

After randomization and allocating participants to 2 groups, those in the control group will receive the usual care. In HF clinic at THC, usual care for patients with HF is limited to a brief instruction by HF specialists on limiting water and salt intake, taking medications as prescribed, physical activity, weight monitoring and increasing the diuretic dosage in the condition of peripheral edema, weight gain, and SOB. They will receive 1 monthly phone call for 3 months. Out of respect for the ethical principles of human research, HF self-care instruction will be provided to the participants in the control group, and they will receive an educational booklet at the end of the study.

Eligible patients will be asked to read and sign a written informed consent form. The research nurse will then collect demographic and clinical characteristics by participant self-reporting and from a medical chart and then record these in data collection forms (see Table 1). Also, participants will be asked to complete baseline surveys (SCHFI, HF knowledge, HFQOL, and health literacy) by themselves in the HF clinic before randomization.

In order to assess participant health literacy, we will use the Heart Failure-Specific Health Literacy Scale with Cronbach alpha=.71. It consists of 12 items each with 4 possible scores (1 to 4): inapplicable (1) to strongly applicable (4) where a higher score indicates a higher level of health literacy except items 1 to 4 [55]. The Iranian version of this scale was prepared after getting the developer’s permission. Thus, it was first translated into Persian by a forward-backward translation method. Then, face and content validity were approved by an expert’s opinion (nursing faculty, nurse practitioners, and cardiologists) and discussion with patients with HF. A pilot study was conducted to assess the reliability with 30 HF patients and where a Cronbach alpha value of .77 was determined. Deletion of items could not improve the value similar to the original scale. Therefore, we decided to retain all items [55]. We will ask the participants to complete the health literacy scale as a baseline survey.

In order to measure the HF knowledge at the end of the study, monthly self-care behavior, and the HFQOL, the outcome assessor will be blinded to study group assignments. The assessor will send the DHFKS, SCHFI, and MLHFQ to the participants in both groups by telegram mobile application in the morning of each monthly call follow-up and ask them to send answers before 6 pm of the same day.

The SPIRIT 2013 template was used to schedule enrolment, interventions, and assessments (Table 1) [34]. A schematic representation of the study design is shown in Figure 5.

In this study, the sample size was calculated based on the minimal clinically important difference (MCID) approach for self-care as measured by SCHFI for the primary outcome. No specific MCID for SCHFI was available to the best of our knowledge and based on our search of the PubMed database.

The suggested MCID for assessing dyspnea with the visual analog scale (0-100 score index) was the range 10-20 [56]. Thus, improving self-care for ≥10 scores from the baseline at the end of the study has been considered as MCID for the present study in order to reach a large sample size. According to the Jurgens et al [22] study in 2013, a mean of 70.8 for self-care in the control group at the end of study (90-days) and a fixed standard deviation of 27.2 (the largest SD) have been considered. In order to calculate sample size by G*Power free software (version 3.1.9.2), the input parameters are as following: effect size (Cohen f) of 0.168, the alpha error probability of .05, a statistical power of 80% to detect MCID≥10 scores between the 2 groups at the end of the study, 3 times measurement of outcome with monthly intervals, and a correlation coefficient of .5 among repeated measurements. Thus, by considering the overall attrition rates of 10%, the sample size was set at 68 participants (34 participants in each group).

During the run-in phase of the study, the research nurse at the HF clinic will be present Sunday through Wednesday of each week from 8 am to 1 pm. The nurse will screen the patients for the eligibility criteria at the time of admission. Participant screening will continue until the target population is achieved. Simultaneously, an HF specialist will confirm the subject`s eligibility and adjust the drug dosages of the eligible participants. Also, the specialist will provide each patient with additional details about the study. This is our main strategy for achieving adequate participant enrollment.

The block balanced randomization method will be used for allocation. Before initiation of the run- in phase of the study, the statistician (AAK) will generate the randomization plan by website Randomization.com [57]. Therefore, twenty blocks of 4 for both the intervention group (group A) and the control group (group B) will be prepared. The statistician will fold the paper containing 4-size blocks 2 times, put them in the standard envelopes and write the serial numbers on them. All envelopes will be kept at the recruitment center. Thus, for every eligible patient, the research nurse randomly selects one of the envelopes after shuffling and assign participants into intervention and control groups.

Due to the nature of the intervention, it is impossible to blind the participants assigned to the study groups to the data collector. However, the outcome assessor will be blinded and instructed not to ask the participants whether or not they received the intervention.

Data will be collected in paper format. A file for each subject will be stored in numerical order in a secure place and manner. Files will be maintained at the recruitment center for 3 years after completion of the study. The statistical expert will prepare the data generated by the IBM/SPSS statistical software (version 16). This expert will train the data clerk to enter the data by specific codes and labels. Also, after finishing the data entry, all data will be double checked. All forms related to the study will be kept in a locked cabinet with restricted access in the recruitment center. All reports will be prepared in a manner in which no individual participants can be identified.

Three researchers from TUMS not involved in the study and chosen by the university will monitor data and supervise the conduct of the study.

Statisticians will prepare the data sheets to collected data. Data will be entered into the SPSS software (version 16). The Kolmogorov-Smirnov test will be used to normality. A transformation approach will be used to handle non-normal distribution. For the between-group comparison of continuous and categorical baseline characteristics, independent t test and chi-square test will be used. For categorical variables between the 2 groups, the two-tailed Fisher exact test will be used instead of the chi-square test in the case of too small expected cell frequencies. A P value <.05 will be considered statistically significant.

The study protocol, data collection forms, educational booklet, and the template of informed consent form was reviewed and approved by the Research Ethics Committee (REC) at TUMS on February 5, 2017 (No. IR.TUMS.FNM.REC.1395.1653). Researchers are committed to updating the agreement with the IRB and REC at TUMS for any administrative and methodological changes of the study protocol which may affect the study.

In order to obtain the informed consent, the research nurse and HF specialist will introduce the trial to each eligible participant. Every eligible participant will receive an information sheet and a written informed consent. The research nurse will then obtain written informed consent from all participants willing to participate in the trial.

The participant informed consent form will be prepared according to the Declaration of Helsinki. It gives the subject information on what the research is about and what happens following participation in the study. It contains information on “purpose of the trial, potential benefits and risks; subject`s right to refuse participation or to withdraw consent at any time; institutional affiliation and potential competing interests of the researcher; and sources of trial funding” [59].

One critical issue that the researchers will be experiencing is posttrial care. Due to the nature of the intervention, this trial will not have any harm for participants that need to be treated during or after the trial. However, the HF specialist is the responsible physician and will assess and manage participants in the event of worsening of the symptoms.

All study-related forms will be stored securely in the recruitment center by code number. Informed consent containing names and other personal identifiers will be stored separately from the forms identified by code number.

Intellectual property of the data belongs to the TUMS research and technology deputy. Thus, the final trial dataset/analysis will be available from the corresponding author upon request and by permission of the TUMS research and technology deputy.