Development and validation of the self‐volume management behaviour questionnaire for patients with chronic heart failure

Abstract

Aims

We aim to develop and validate a questionnaire on the behaviour of self‐volume management of patients with chronic heart failure.

Methods and results

Based on the specific situation theory of heart failure self‐care, the items of this questionnaire were formed through literature review and expert consultation. Content validity is judged by expert consultation. Item analysis was used for further filter entries. Cronbach's alpha and retest were used for reliability. Exploratory factor analysis and confirmatory factor analysis were used to test the structural validity. The questionnaire finally contained 3 subscales and 22 items. The Cronbach's α was between 0.732 and 0.797. The reliability of the retest was between 0.983 and 0.998. In expert consultation, the I‐CVI of each item was 0.92–1, and the S‐CVI of each subscale was 0.99, 1.00, and 0.99. In exploratory factor analysis, each subscale has two factors. In confirmatory factor analysis, the model fits of the three subscales were good: χ ²/df < 3, RMSEA < 0.08, CFI > 0.9, TLI > 0.9, and SRMR < 0.05.

Conclusions

The study has shown that the questionnaire on the behaviour of self‐volume management of patients with chronic heart failure has good reliability and validity. It can be used as an evaluation tool for evaluating the self‐volume management behaviour of patients with chronic heart failure.

Introduction

Chronic heart failure (CHF) is a persistent state of heart failure. Approximately 64.3 million individuals worldwide suffer from CHF, and the incidence has been rising recently, especially among the elders. ¹ , ² Patients with CHF are often repeatedly admitted to the hospital due to insufficient symptom management skills, which seriously affects the quality of life of patients, brings greater economic and care giving burdens to their families, and causes greater pressure on public health management. ³ , ⁴

Volume overload is one of the most important patho‐physiological changes faced by patients with CHF in self‐management. The symptoms and signs of volume overload, including sudden weight gain, dyspnoea, and peripheral circulating water, have been proven as the main reasons for unplanned admissions and HF‐related deaths. ⁵ , ⁶ Low cardiac output and less effective circulating blood volume set off a range of compensatory processes in the human body, while the triggers (e.g., infection) may easily result in hemodynamic abnormalities, fluid retention, and volume overload. Volume overload can cause pulmonary and systemic congestion, compensatory fluid redistribution, interstitial fluid retention, and various organ physiological dysfunction. ⁷ Volume overload actually exists for a long time prior to the onset of HF congestion symptoms. The manifestation of the symptoms and signs indicates the severe condition of volume overload, and the patient may immediately enter the HF decompensation phase. ⁸ Therefore, volume management is the top priority of health education for patients with CHF and self‐volume management is essential for patients with CHF to prevent the progress of HF and improve their quality of life.

Although no exact definition of volume management in patients with CHF exists, the objectives of volume management usually include hemodynamic stabilization, preventing volume overload, and assisting patients in achieving the ideal fluid balance state. Diuretic use, volume status monitoring, and lifestyle modification (fluid restriction and dietary sodium restriction) are three major components of volume management. ⁷ Therefore, it is vital to pay more attention to these major components of volume management behaviour of patients with CHF to manage their volume status.

We discovered that earlier research on volume management in people with CHF had a strong emphasis on medication and physiological evaluation. ⁹ , ¹⁰ Although the volume management of patients with CHF has attracted the attention of Chinese medical staff in recent years, ¹¹ , ¹² there has always been a lack of research on volume management from the perspective of patients. However, studies on volume management from the patient's perspective are scarce. Patients' perspectives can reflect patients' deficiencies intuitively, help to improve disease care strategies, and serve as a foundation for patient–nurse decision‐making. ¹³ Thus, it is critical to investigate how patients with CHF perceive the assessment of volume management behaviour.

The Situation‐Specific Theory of Heart Failure Self‐Care is a theory from the perspective of patients, which deeply explains the decision‐making process of self‐care behaviour of heart failure patients. ¹⁴ It contains three independent and interrelated stages, which are often manifested as progressive structural relationships, namely self‐care maintenance‐symptom perception‐ self‐care management. ¹⁵ Our research focused on self‐volume management in self‐care. This theory was in line with our original intention of the research assumption and laid a solid foundation for our research.

To the best of our knowledge, there are few studies focusing on the self‐volume management behaviours of patients with CHF in China. There are many questionnaires that could be used for symptom management assessment and self‐management behaviour in patients with CHF. ⁵ , ¹⁶ However, the deficiencies of these instruments include overlooking the details of volume management, utilizing overly general wording that might vaguely reflect the current status of volume management, or lacking disease‐specificity. And there is no suitable evaluation instrument for the self‐volume management behaviour of patients with CHF. The primary aim of this study was to create a questionnaire to evaluate the self‐volume management behaviour of patients with CHF. This questionnaire can help medical staff understand the current status of self‐volume management behaviour of CHF, and develop targeted volume management interventions based on feedback from relevant item scores.

Methods

Design and participants

Convenience sampling is used to select patients with CHF from comprehensive secondary and tertiary hospitals in Shanghai, China. The data were collected from July 2021 to February 2022. There is no material compensation for the participants.

Participants were included following the inclusion criteria: Patients (1) who met the diagnostic criteria for CHF ¹⁷ and were diagnosed with chronic heart failure by a cardiovascular specialist, (2) with New York Heart Association (NYHA) Cardiac Function Grade II–IV, ⁴ (3) aged at least 18 years, (4) who can complete the questionnaire independently or with the help of the researcher. A uniform interpretation for patients with low literacy rates or questions about the items is developed. Exclusion criteria: Patients (1) who do not need to take diuretics, (2) who are judged to be unable to participate in the study for any other reason (e.g., psychiatric disorder and life‐threatening co‐morbidity), (3) who have been unable to take care of themselves for a long time.

Sample size

According to the requirements of factor analysis, the sample size required for exploratory factor analysis (EFA) is 5–10 times the number of items, and the sample size of confirmatory factor analysis (CFA) should be at least 200 cases in addition to meeting this standard. ¹⁸ Considering 5–10 subjects per item and 23 items of the questionnaire, the sample size required in the first stage was between 115 and 230. Two trained investigators (L. Z. L. and R. T. T.) collected data face‐to‐face. After signing the informed consent forms, they filled out the research questionnaire. The study was conducted on the ethical principles from the Declaration of Helsinki and had been annotated by the Ethics Committee of Shanghai Sixth People's Hospital (No. 2021‐231, Date: 28 October 2021). Written informed consent will be obtained from all participants prior to study enrolment, and they could withdraw from the study if they felt uncomfortable.

Questionnaire development

Phase 1: Create initial items

The questionnaire was originally written in Chinese. The researchers who have been trained in systematic evidence‐based methodology summarized the best evidence of self‐volume management in patients with CHF from the five guidelines and two expert consensus. ¹⁹ The initial 25 items for the questionnaire were generated from the evidence (L. Z. L. and R. T. T.). Based on the Situation‐Specific Theory of Heart Failure Self‐Care, the initial structures of the self‐volume management behaviour questionnaire for patients with CHF was formed, comprising three subscales. The three subscales include (1) ‘Maintenance of Self‐volume management’ (11 items), to evaluate the performance of self‐volume management behaviours such as diuretics and dietary sodium and fluid intake restriction in patients with CHF during daily self‐care; (2) ‘perception of volume overload’ (9 items), to evaluate the monitoring and identification of common symptoms and signs of volume overload in patients with CHF; (3) ‘coping with volume overload’ (5 items), to evaluate coping behaviour in patients with chronic heart failure when symptoms and signs of volume overload are present.

Through discussion, the research team prepared the general information questionnaire to investigate the patient's socio‐demographic information (variables included age, gender, education level, marital status, occupation, mode of residence, medical insurance status, etc.) and disease information (variables included diagnosis, comorbidities, drug use, LVEF value, length of illness, number of hospitalizations, BNP, etc.).

Phase 2: Initial assessment of the items

At this stage, we invited cardiologists (n = 2), chronic disease management specialists (n = 6), and nursing research experts (n = 5) to review these items. Likert 4 scale was to used to assess whether items were suitable for assessing self‐volume management behaviour in patients with CHF, with 1 = very unsuitable; 2 = need to be modified, otherwise, it is not suitable; 3 = fair but still modifiable; 4 = very suitable and propose modifications. Expert ratings were summarized for the calculation of content validity. Evaluation of the content validity is completed during expert consultation. The item‐level content validity index (I‐CVI) is calculated based on the number of experts with an item score of ‘3’ or ‘4’ divided by the total number of experts. The scale‐level content validity index (S‐CVI) is the mean of I‐CVI. I‐CVI more than 0.78, and S‐CVI more than 0.80 are preferred. ²⁰

After two rounds of expert consultation, three items were removed from the first subscale. ‘Adjust diuretics for changes in weight and symptoms’ was removed, which has a similar meaning to ‘Taking diuretics’ in the third dimension. ‘Choose a low‐salt diet when eating out’ and ‘Choose a low‐salt diet when visiting friends and relatives’ were merged into one item (No. 5). ‘Whether there is a habit of consuming specific liquids (e.g., milk, tea …)? What is the daily intake?’ was removed. Because this item is difficult for patients to answer and coincides with the item ‘Utilize tools or methods for estimating the daily fluid intake’. At the same time, one item ‘going to the doctor or consulting a medical staff for guidance or consulting a medical staff for guidance’ in the third subscale was split into two items (No. 22, 23). Thus, the questionnaire was finalized with three subscales and 23 total items.

Phase 3: Refining the questionnaire and testing psychometric properties

At this stage, we used item analysis, reliability tests, and validity tests to assess the psychometric attributes of the questionnaire. Data were statistically analysed using IBM SPSS 20.0 and Mplus v8.3 software. The test level was taken as bilateral P < 0.05, which was statistically significant. Socio‐demographic and health‐related variables would be reported descriptively.

The critical ratio (CR) value method and Pearson correlation analysis method are used for item analysis. The degree of differentiation of the items was evaluated. The questionnaire's overall scores were ranked from high to low. The top 27% of the research subjects and the bottom 27% of the research subjects were designated, respectively, as the high group and the low group. ²¹ An independent‐sample t‐test using the means of the two groups for each entry and assessing the degree of differentiation of the scores of each item between the high group and the low group was conducted. The representativeness of the items was assessed and the association between the scores for each item and the sub‐overall questionnaire's score was examined using the Pearson Correlation Analysis. Any items that showed a lack of contributions to internal consistency reliability, lack of discrimination capacity, or lack of representativeness were removed. ²¹ , ²²

EFA and CFA were used to evaluate the validity of the structure of the questionnaire. Kaiser–Meyer–Olkin (KMO) > 0.5 and Bartlett spherical test P < 0.01 are the prerequisites for EFA. To extract the factors with an eigenvalue of more than 1, the principal component analysis method and varimax‐rotation method were chosen for hierarchical factor analysis. During exploratory factor analysis, the eigenvalue, the inflection point of the scree plot, and cumulative variance contribution rate >50% were comprehensively considered to determine the optimal number of factors.

We performed CFA based on the Situation‐Specific Theory of Heart Failure Self‐Care and the results of EFA. In CFA, the model fit was determined based on the following criteria: chi‐square to the degree of freedom ratio (χ ²/df) < 3, the root mean square error of approximation (RMSEA) < 0.080, the comparative fit index (CFI) > 0.90, and the Tucker–Lewis index (TLI) > 0.90 and the standardized root mean square residual (SRMR) < 0.050. ¹⁸ , ²³

The reliability of the scale was assessed by internal consistency reliability and test–retest reliability. Cronbach's α coefficient more than 0.70 indicates good reliability. Test–retest reliability was used to confirm the stability of the questionnaire. Eighteen patients with CHF who met the inclusion and exclusion criteria were randomly selected to fill out the questionnaire again 3 weeks after the initial measurement. Intraclass correlation coefficient (ICC) > 0.70 indicates good reliability. ²¹ , ²⁴

Results

A total of 358 valid data were collected (150 for the first stage and 208 for the second stage). Socio‐demographic and health‐related variables on the subjects are shown in Table 1 .

Table 1.

Sociodemographic and health‐related variables of participants (n = 358)

Variables	Group 1 (N = 150)		Group 2 (N = 208)
	x̅ ± s	N (%)	x̅ ± s	N (%)
Age (years)
	71.60 ± 11.69		71.51 ± 12.93
Gender
Male		97 (64.71)		128 (61.5)
Female		53 (35.33)		80 (38.5)
Marital status
Married		106 (70.67)		145 (69.7)
Single a		44 (29.33)		63 (30.3)
Living status
Alone		20 (13.33)		24 (11.5)
With a spouse		65 (43.33)		98 (47.1)
With children		27 (18.00)		37 (17.8)
With spouse and children		34 (22.67)		40 (19.2)
Others		4 (2.67)		9 (4.3)
Education
Primary School or under		47 (31.33)		57 (27.4)
Junior high school		54 (36.00)		60 (28.8)
High school or above		49 (32.67)		91 (43.8)
Course of disease (years)
≤1		57 (38.00)		100 (48.08)
1 < y ≤ 4		51 (34.00)		57 (27.40)
4 < y ≤ 10		38 (25.33)		42 (20.19)
≥10		4 (2.67)		9 (4.33)
NYHA
II		63 (42.00)		99 (47.6)
III		61 (40.67)		109 (52.4)
IV		26 (17.33)		0 (0.00)
Complication
Coronary heart disease		70 (46.67)		129 (62.0)
Myocardial infarction		31 (20.67)		62 (29.8)
Atrial fibrillation		49 (32.67)		68 (32.7)
Dilated cardiomyopathy		16 (10.67)		31 (14.9)
Hypertension		89 (59.33)		132 (63.5)
Diabetes		39 (26.00)		68 (32.7)
Cerebral infarction		9 (6.00)		21 (10.1)
COPD		4 (2.67)		9 (4.3)

COPD, chronic obstructive pulmonary disease; NYHA, New York Heart Association.

^a These include unmarried, divorced or separated, and widowed.

Item analysis

(1) CR value. The differentiation results of each item are shown in Table 2 . With the exception of Item 23 (P > 0.05), all items showed a good degree of differentiation between high and low groupings (P < 0.01).

Table 2.

The critical ratio value and Pearson correlation

Items	t	P	r
Maintenance of Self‐volume management
1 Take diuretics on time and in the right dose according to your doctor's recommendations.	3.294	0.002	0.468 **
2 Regularly consult the medical staff about the medication plan of diuretics (including drug name, dosage, time, frequency, purpose, adverse reactions, and precautions).	6.190	0.000	0.677 **
3 Regular blood tests to monitor the side effects of diuretics (including serum potassium, serum sodium and other electrolyte indicators, and renal function indicators).	5.200	0.000	0.629 **
4 Adjust diet according to the recommendations of medical staff (such as a low‐salt diet or appropriately increase sodium intake, eating foods high in potassium).	6.207	0.000	0.659 **
5 Choose low‐salt meals when you eat out.	7.009	0.000	0.683 **
6 Pay attention to the sodium content listed on food packaging.	7.641	0.000	0.749 **
7 Use measuring spoons or other methods to gauge how much salt is being used when eating or cooking at home.	7.165	0.000	0.691 **
8 Utilize tools or methods for estimating the daily fluid intake (including all liquids like water, soup, etc.).	6.217	0.000	0.566 **
Perception of volume overload
9 Weigh yourself at a fixed time every day.	7.976	0.000	0.605 **
10 Measure blood pressure and heart rate every morning.	7.638	0.000	0.629 **
11 Pay attention to whether there is chest tightness and shortness of breath in daily activities.	3.255	0.002	0.476 **
12 Check whether there is oedema in the calves, ankles, and other parts.	6.037	0.000	0.569 **
13 Pay attention to whether you have bloating, increased abdominal circumference, or loss of appetite.	4.199	0.000	0.542 **
14 Focus on whether you are tired more easily than usual during your daily activities.	3.957	0.000	0.595 **
15 Pay attention to whether there is a change in urine output every day.	4.184	0.000	0.556 **
16 Make a note of the symptoms that appear.	6.261	0.000	0.606 **
17 Pay close attention to whether you have new symptoms.	5.224	0.000	0.549 **
Coping with volume overload
18 Adjust diuretics according to the guidance of medical staff (such as upping the dosage or taking an additional medication).	7.047	0.000	0.605 **
19 Further reduce salt in your diet for the day.	7.489	0.000	0.788 **
20 Further reduce the intake of liquids (water, soup, etc.) on the day.	9.238	0.000	0.795 **
21 Seek help from family or friends.	4.307	0.000	0.659 **
22 Consult medical staff for guidance by telephone, WeChat, or other online channels.	5.101	0.000	0.704 **
23 Go to the hospital.	1.707	0.092	0.282 **

r is the Pearson correlation coefficient between the score of each item and the score of the sub‐questionnaire.

^* P < 0.05.

^** P < 0.01.

(2) Pearson correlation analysis. The correlation coefficient results of each item and subscale score are shown in Table 2 . With the exception of Item 23, item‐total correlations for all other items ranged from 0.468 to 0.795, while the correlation coefficient for Item 23 was 0.282, which was lower than the cut point >0.30. ²²

Pre‐reliability test

The Cronbach's α coefficients of the three subscales ranged from 0.724 to 0.797. Due to Item 23 showing both a lack of discrimination capacity and a lack of contribution to the homogeneity of the subscale in the item analyses, Cronbach's alpha was calculated both with and without Item 23. When Cronbach's alpha without Item 23 was calculated, it was 0.765, increased from 0.724 with Item 23. Thus, Item 23 was removed because of the results.

Validity

• 1Content validity

In this study, the I‐CVI of each item was 0.92–1, and the S‐CVI of each subscale was 0.99, 1.00, and 0.99.

• 2Construct validity

Exploratory factor analysis

• ①Maintenance of self‐volume management

At this level, Kaiser–Meyer–Olkin (KMO) = 0.791 and Bartlett spherical test P < 0.01. Two factors were extracted, and the cumulative variance contribution rate was 57.102%. The composition of the extracted factors is consistent with the theory, see Table 3 . Items around diuretic use are grouped as ‘taking diuretics’(e.g., ‘Take diuretics on schedule and in the amount recommended by your doctor.’ Items 1–3). And items around eating and drinking are grouped as ‘Limiting water and sodium intake’(e.g., ‘Pay attention to sodium content on food packaging.’ Items 4–8).

• ②Perception of volume overload

Table 3.

The factors of the level of maintenance of self‐volume management (N = 150)

No.	Factors
	Limiting water and sodium intake	Taking diuretics
6	0.800
7	0.792
5	0.681
4	0.645
8	0.633
2		0.792
1		0.764
3		0.719

Rotation converges after three iterations.

At this level, KMO = 0.754 and Bartlett spherical test P < 0.01. Two factors were extracted, and the cumulative variance contribution rate was 48.664%. The extracted factor composition was consistent with the theory, see Table 4 . Items describing the patient's detection and recognition of basic physical signs and changes are grouped as ‘Perception of Somatic Symptoms/Signs’ (e.g., ‘Measuring blood pressure and heart rate every morning.’ Items 9–10, 16–17). Items describing detection and recognition of symptoms and signs of volume overload go to ‘Perception of volume overload symptoms/signs’ (e.g., ‘Focus on changes in urine output from day to day.’ Items 11–15).

• ③Coping with volume overload

Table 4.

The factors of the level of perception of volume overload (N = 150)

No.	Factors
	Perception of volume overload symptoms/signs	Perception of somatic symptoms/signs
13	0.744
14	0.729
12	0.709
11	0.567
15	0.484
16		0.791
10		0.770
9		0.669
17		0.559

Rotation converges after three iterations.

Item 23 gets removed from this level after the inspection procedures because it is poorly differentiated and unrepresentative. At this level, KMO = 0.672 and Bartlett spherical test P < 0.01. A total of 2 factors were extracted, and the cumulative variance contribution rate was 74.469%. The composition of the extracted factors was consistent with the theory, and the included items were in line with the hypothesis, see Table 5 . In ‘coping with volume overload’, items describing self‐regulating behaviours are classified as ‘self‐adjustment behaviours’ (e.g., ‘Further reducing salt in your diet for the day.’ Items 18–20) and items describing consulting others as ‘Counselling behaviours’ (e.g., ‘Ask family or friends for help.’ Items 21–22).

Table 5.

The factors of the level of coping with volume overload (N = 150)

No.	Factors
	Self‐adjustment behaviours	Counselling behaviours
19	0.885
20	0.863
18	0.740
21		0.851
22		0.831

Rotation converges after three iterations.

Confirmatory factor analysis

Confirmatory factor analysis is used to further validate the factor model created after EFA. Mplus8.3 software was used to build the model utilizing the data gathered during the second step (Group 2). Based on the Situation‐Specific Theory of Heart Failure Self‐Care and the results of EFA, the three subscales were validated separately. ²⁵ ‘Maintenance of Self‐volume management’ has two factors called ‘taking diuretics’ and ‘limiting water and sodium intake’(see Figure 1 ). ‘Perception of volume overload’ has two factors called ‘perception of somatic symptoms/signs’ and ‘perception of volume overload symptoms/signs’ (see Figure 2 ). ‘Coping with volume overload’ has two factors called ‘self‐adjustment behaviors’ and ‘counselling behaviours’ (see Figure 3 ). The χ ²/df ratios in the three subscales were 1.647, 1.693, and 1.335, respectively. The RMSEAs in the three subscales were 0.056, 0.049, and 0.046, respectively. The CFIs in the three subscales were 0.973, 0.959, and 0.993, respectively. The TLIs in the three subscales were 0.958, 0.938, and 0.983, respectively. The SRMRs in the three subscales were 0.038, 0.043, and 0.022, respectively (Table  6 ). The model fits well and conforms to the idea.

Figure 1.

Maintenance of self‐volume management. Note: ‘1’ means ‘taking diuretics’; ‘2’ means ‘limiting water and sodium intake’; ‘a’ means ‘No.’.

Figure 2.

Perception of Volume Overload. Note: ‘1’ means ‘perception of somatic symptoms/signs’; ‘2’ means ‘perception of volume overload symptoms/signs’; ‘a’ means ‘No.’.

Figure 3.

Coping with volume overload. Note: ‘1’ means ‘self‐adjustment behaviours’; ‘2’ means ‘counselling behaviours’; ‘a’ means ‘No.’.

Table 6.

The result of confirmatory factor analysis (N = 208)

Subscale	χ 2 /df	RMSEA	CFI	TLI	SRMR
Maintenance of self‐volume management	1.647	0.056	0.973	0.958	0.038
Perception of volume overload	1.693	0.049	0.959	0.938	0.043
Coping with volume overload	1.335	0.046	0.993	0.983	0.022

χ ² /df means chi‐square to the degree of freedom ratio.

CFI, comparative fit index; RMSEA, root mean square error of approximation; SRMR, standardized root mean square residual; TLI, Tucker–Lewis index.

Reliability

• 1Internal consistency reliability

The Cronbach's α coefficients of the three subscales ranged from 0.732 to 0.797. The Cronbach's α coefficients of the six factors ranged from 0.520 to 0.775 (see Table 7 )

• 2Test–retest reliability

Table 7.

Reliability tests

Subscale	Cronbach's α		Test–retest reliability
Maintenance of Self‐volume management	0.797		0.995*
‐ Limiting water and sodium intake		0.775
‐ Taking diuretics		0.715
Perception of volume overload	0.732		0.983*
‐ Perception of volume overload symptoms/signs		0.699
‐ Perception of somatic symptoms/signs		0.605
Coping with volume overload	0.765		0.998*
‐ Self‐adjustment behaviours		0.717
‐ Counselling behaviours		0.520

^* P < 0.01.

ICC of the scores measured by each subscale was between 0.983 and 0.998 (Table  7 ), all of which were statistically significant (P < 0.01).

Summary

After the above steps, the questionnaire on the behaviour of self‐volume management in patients with chronic heart failure (see Data S1 ) is composed of three subscales: maintenance of self‐volume management (8 items), perception of volume overload (9 items), and coping with volume overload (5 items) was formed, which was tested to have good reliability, and validity in the target population, and could be used as an effective tool for self‐volume management behaviour assessment of patients with CHF.

Discussion

According to our knowledge, this study was one of the first studies to develop a self‐volume management behaviour questionnaire for patients with CHF in China. With respect to the maintenance of self‐volume management, perception of volume overload, and coping with volume overload, this questionnaire assessed the self‐volume management behaviour in patients with CHF comprehensively. It is a trustworthy instrument that can direct medical workers in volume management.

Item 23 (‘going to the hospital’) was removed during the first stage based on lack of discrimination capacity, lack of contribution to the homogeneity of the subscale, and increase in Cronbach's alpha without this item. In addition, the authors found a theoretical mismatch between the item and the purpose of the subscale. This item assesses patients after self‐response was ineffective. However, the purpose of the scale was intended to measure the self‐management and response measures taken by patients when they experienced volume overload. Thus, Item 23 was removed from this scale. The reliability of the three subscales was supported by Cronbach's α coefficients >0.70 and ICCs between 0.983 and 0.998. ²⁴

We also tested the reliability of each of the six factors. However, the results of ‘perception of volume overload symptoms/signs’, ‘perception of somatic symptoms/signs’ and ‘counselling behaviours’ are unsatisfactory. There are two main reasons for this. First, the smaller number of items. Reliability indicates how well a set of items in a scale or subscale measures a single, unidimensional construct. When the number of items in a scale is small, there are fewer opportunities for covariance and lack of shared construct among items and more sensitivity to any variations in how individual items contribute to the overall measurement. ²⁵ Second, there is a subtle effect on the content of the items. For ‘perception of volume overload symptoms/signs’ and ‘perception of somatic symptoms/signs’, patients with heart failure have different levels of knowledge about different symptoms, thus there will be subtle differences in the degree of attention. ²⁶ For ‘counselling behaviours’, the two items are related to support from family and friends vs. healthcare providers. The differences in the nature and characteristics of the two different types of support may cause a lack of a single, unidimensional construct, which decreases Cronbach's alpha. ²⁷ , ²⁸

When conducting the questionnaire reliability and validity test, we referred to the test method of heart failure self‐care index based on the specific situation theory of heart failure self‐care. ²⁹ The questionnaire was divided into three subscales and measured separately. This way can not only detect the psychological measurement attributes of questionnaires but also increase the diversity of questionnaire applications. All three subscales have good reliability and validity. When measuring self‐volume management behaviour in patients with CHF, the three subscales can be used alone or in combination.

The self‐volume management behaviour questionnaire for patients with chronic heart failure was developed and validated in this study based on the Situation‐Specific Theory of Heart Failure Self‐Care, which makes up for the lack of Chinese research on volume management in patients with chronic heart failure. However, since there is no mature scale to assess the behaviour of self‐volume management in patients with CHF, we have not tested the validity of the calibration association of the questionnaire. Further multi‐regional and large‐sample surveys can be carried out in the future to increase the applicability of the questionnaire. Due to the small number of items that each factor contains, the reliability of each factor is not good. Follow‐up investigators could explore more advanced statistical methods for deeper reliability testing.

We include examples in English in the table to help readers better comprehend the questionnaire items. In order to better serve patients with chronic heart failure in various countries, the authors will make the questionnaire available in Chinese and encourage researchers from other nations to adapt it in terms of language and culture.

Conclusions

Based on the Situation‐Specific Theory of Heart Failure Self‐Care, a tool is developed to evaluate the maintenance of self‐volume management, perception of volume overload, and coping with volume overload in patients with CHF. The reliability and validity were proved in the study. This questionnaire can provide a reliable evaluation for medical staff and be used for the construction of a protocol for the self‐volume management behaviour of patients with CHF.

In addition, it would be useful to assess how this questionnaire performs in patients with CHF from other cultures with similar/dissimilar medical backgrounds. Cross‐cultural validation could visualize the cultural specificity of different countries to better assess the self‐volume management behaviour of patients with CHF in each country.

Conflict of interest

None declared.

Funding

None.

Supporting information

Data S1. Supporting Information.

Luo, Z. , Ruan, T. , Xu, M. , Ding, Y. , and Zhu, L. (2024) Development and validation of the self‐volume management behaviour questionnaire for patients with chronic heart failure. ESC Heart Failure, 11: 1076–1085. 10.1002/ehf2.14656.