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Special Topic: Caregiving

Validity and Reliability of the Caregiver Contribution to Self-Care of Heart Failure Index Version 2

Vellone, Ercole PhD, RN, FESC; Barbaranelli, Claudio PhD; Pucciarelli, Gianluca PhD, RN, FAHA; Zeffiro, Valentina PhD, RN; Alvaro, Rosaria MSN, RN, FAAN; Riegel, Barbara PhD, RN, FAAN

Author Information
The Journal of Cardiovascular Nursing: 5/6 2020 - Volume 35 - Issue 3 - p 280-290
doi: 10.1097/JCN.0000000000000655
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Abstract

Heart failure (HF) has become pandemic worldwide and is increasing its prevalence and incidence because of improvements in the treatment of ischemic cardiopathy and the aging of the population.1 Patients affected by HF are comparable with patients affected by cancer in terms of the burden of symptoms, poor quality of life, and high mortality.2 Heart failure is also associated with repeated hospitalizations and high healthcare cost.3 A recent systematic review estimated that the lifetime costs associated with HF are $126 819 per patient.3

Patients with HF have to comply with a strict, burdensome, and permanent regimen consisting of numerous self-care behaviors such as physical activity, monitoring signs and symptoms, and taking, on average, 13 medications daily.4,5 These self-care behaviors have been shown to improve mortality, quality of life, and hospitalization rates.6

Although self-care is so important for patients with HF, studies show that self-care is inadequate.7 Older age, cognitive impairment, depression, and lack of confidence and motivation are some of the main reasons for poor self-care.7–9 However, social support and the help of a caregiver (eg, a family member) can improve patient self-care10,11 and reduce clinical event risks.12

To measure caregiver contributions (CC) to self-care of HF, we developed the Caregiver Contribution to Self-Care of Heart Failure Index (CC-SCHFI).13 In the article describing development of the CC-SCHFI, we defined CC to HF self-care as “the provision of time, effort, and support on behalf of another person who needs to perform HF self-care” (p 246).

The CC-SCHFI was derived from the Self-Care of Heart Failure Index version 6.2 (SCHFI v.6.2),14 an instrument that measures HF patient self-care, with the same number of items (22) and scales (self-care maintenance, self-care management, and self-care confidence). The only difference between the 2 instruments is that, in the in the SCHFI v.6.2, we ask patients how often they performed self-care behaviors, for example, physical activity, during the last month; in the CC-SCHFI, we ask caregivers how often they recommended the same self-care behaviors to the patients. After the publication of the development article, the CC-SCHFI was adopted in several studies15–17 and currently is available in 12 languages (www.self-care-measures.com).

The CC-SCHFI has been always linked with the SCHFI v.6.2, and when the SCHFI v.6.2 was revised to produce version 7.2,18 with the scales of maintenance, symptom perception, and management, we revised the CC-SCHFI to reflect the same number of items (29) and scales. In addition, with the publication of the Situation-Specific Theory of Caregiver Contributions to Heart Failure Self-Care19 with the concepts of CC to self-care maintenance, CC to symptom monitoring and perception, and CC to self-care management, it became important to develop an instrument reflecting the theory. The previous version of the CC-SCHFI, with the concepts of CC to self-care maintenance, management, and caregiver confidence, reflected the SCHFI v.6.2 but was not based on any theory of CC to HF self-care. In this study, we have tested the psychometric characteristics of the CC-SCHFI 2. We believe that a match between the CC-SCHFI 2 and the theory will support development of the science in this specific field. In addition, we believe that a match between the CC-SCHFI 2 and the SCHFI v.7.2 will be helpful to investigators wishing to conduct dyadic studies.

Methods

Design and Ethical Considerations

We used a cross-sectional design. Approval was obtained from the institutional review board of 1 site where participants were enrolled (letter n° 2424/2016 – Lazio 1). We informed caregivers and patients of the study aims and obtained their signed informed consent, and then participants were asked to complete the battery of the instruments used for this study.

Sample and Settings

We used a convenience sample and recruited caregivers in several outpatient settings in the central Italy. Caregivers were eligible for the study if they (1) were primary caregivers of a patient affected by HF (by definition, the primary caregiver was the person who provided most of the informal care to the patient), (2) were 18 years or older, and (3) were able to understand and speak the Italian language. Patients cared for by our caregivers (1) had a diagnosis of HF, according to the guidelines of the European Society of Cardiology,5 in New York Heart Association (NYHA) functional classes I to IV; (2) did not have severe cognitive impairment, defined as a score of less than 4 on the Six-Item Screener20; (3) had not experienced a coronary event in the preceding 3 months; (4) were 18 years or older; and (5) were able to understand and speak the Italian language.

Procedures of Data Collection

After identifying potential participants who met the eligibility criteria, research assistants, who were all nurses trained for this study protocol, proposed the study to caregivers and patients with HF, explaining the aim of the study and the procedures for data collection. Specifically, research assistants informed HF caregivers and patients that, after they had signed the consent form, they would be asked to complete the research instruments and have clinical data collected from the patient's medical record (eg, NYHA class and comorbid conditions). Data were collected in outpatient settings with a face-to-face interview. The CC-SCHFI 2 was also administered by telephone after 2 weeks for test-retest reliability.

Instruments

The CC-SCHFI 2 is a 29-item instrument that includes 3 scales: CC to self-care maintenance, CC to symptom perception, and CC to self-care management. As reported earlier, the CC-SCHFI 2 was derived from the SCHFI 7.2 with the same number of items and scales. In the development of the CC-SCHFI 2, we only changed the introduction of each scale to investigate how often caregivers recommend self-care behaviors to the patients (eg, get some exercise) or how often caregivers did some activities because the patients were not able to do them (eg, use a system or method to help the patient to remember to take medicines). In addition, we changed the wording of some items of the CC to symptom perception and self-care management to make it clear that symptoms and their management were referred to patients. For example, in the symptom perception scale of the SCHFI 7.2, we ask patients whether they “pay attention to changes in how you feel.” However, in the CC-SCHFI 2, the corresponding item asks caregivers whether they “pay attention to changes in how he/she (ie, the patient) feels.” The CC to self-care maintenance scale includes 10 items and asks the caregiver to report how often he or she recommends that the patient perform behaviors aimed at maintaining HF stability (eg, taking prescribed medicines without missing a dose). The CC to symptom perception scale has 11 items and asks the caregiver to report how often he or she recommends that the patient monitor common signs and symptoms of HF such as daily weight or medicine side effects. Finally, the CC to self-care management scale, with 8 items, asks the caregiver to report how likely he or she is to recommend behaviors aimed at responding to an HF exacerbation such as limiting fluid intake or calling the healthcare professional for guidance in case of symptoms.

Each CC-SCHFI 2 scale has a standardized score from 0 to 100, with higher scores indicating better self-care. The CC to self-care maintenance scale uses a 5-point Likert format for responses from “never” to “always.” Nine items of the CC to symptom perception scale use the same Likert format of the CC to self-care maintenance scale for responses. Two items measuring symptom recognition have 7 response options that use a skip-pattern format. These items use a 5-point Likert response format (“not quickly” to “very quickly”) plus 2 additional responses (“I did not have symptoms” and “I did not recognize the symptom”). If these negative responses are chosen, the items are not considered in the computation of the total scale score because it means that the patient did not have symptoms so the caregiver was not able to recognize them. Because the total scale score is standardized from 0 to 100, the previously mentioned responses do not modify the total score. The CC to self-care management scale uses a 5-point Likert format for responses (“not likely” to “very likely”). However, 1 item measuring treatment evaluation uses a skip-pattern format with the option “I did not do anything.” If the caregiver selects this option, the item is not considered for the total scale score. As for the previously mentioned example, because the total scale score is standardized, this response does not alter the scale score. A score of 70 or greater is considered adequate CC to self-care on each scale. This cutoff is based on previous studies performed on the SCHFI v.7.2.18

The Caregiver Contribution to Heart Failure Self-Care Scale (CACHS)21 is a 20-item instrument that also measures CC to HF self-care. Different from the CC-SCHFI 2 that was developed by modifying into a caregiver version of the SCHFI v.7.2, the CACHS was developed using qualitative interviews.22 Caregivers of patients with HF were asked to report their contributions in the dimensions of self-care maintenance (8 items; eg, take responsibility for making sure patient pills are organized), self-care monitoring (7 items; eg, watching for any changes in patient breathing), and self-care management (5 items; eg, talking to the patient to help figure out what he or she is feeling). The CACHS was tested with an item response theory approach that resulted in a high discrimination (median, 2.13) and appropriate item difficulty (−2.7 to 1.4). Internal consistency reliability was also supportive with a Cronbach α of .94.

The SCHFI v.7.218 is a 29-item instrument consisting of 3 scales: self-care maintenance, symptom perception, and self-care management. The self-care maintenance scale consists of 10 items and measures the extent to which a patient with HF is engaged in behaviors that help maintain HF stability (eg, seeing the healthcare provider for routine healthcare). The symptom perception scale includes 11 items and measures how often a patient monitors HF signs and symptoms (eg, body weight). The self-care management scale consists of 8 items that measure the response to signs and symptoms of an HF exacerbation (eg, limiting activity until feeling better). Each item of each scale uses a 5-point Likert scale for responses and the embedded screening questions, as described in the CC-SCHFI 2. The total score per each scale is standardized from 0 to 100, with higher scores indicating better self-care. A score of 70 or greater is considered adequate self-care. The SCHFI v.7.2 was tested with confirmatory factor analysis (CFA) that revealed supportive fit indices for the 3 scales (comparative fit index [CFI] from 0.96 to 0.97; root mean square error of approximation [RMSEA] from 0.031 to 0.050). Reliability tested with the global reliability index for multidimensional scales ranged between 0.70 and 0.85 among the 3 scales.

We used the CACHS and the SCHFI v.7.2 to test concurrent validity. Because the CC-SCHFI 2 measures CC to HF self-care, we hypothesized a significant correlation with the CACHS because the CACHS also measures CC to HF self-care. We hypothesized a significant correlation between the CC-SCHFI 2 and the SCHFI v.7.2, because caregivers who contribute better to patient self-care should be associated with better self-care in patients.

Statistical Analysis

The statistical analysis was performed in 5 steps. In the first step, descriptive statistics (eg, mean and SD) were used to describe the sample characteristics (eg, caregiver age and gender) and CC-SCHFI 2 items (eg, skewness and kurtosis). In the second step, CFA was used to test the factorial structure of the CC-SCHFI 2. The 3 CC-SCHFI 2 scales were tested separately considering the same factorial structure of the SCHFI v.7.2.18 Specifically, we hypothesized the following factors in the CC to self-care maintenance scale: dietary behaviors (items 3, 6, and 8) and consulting behaviors (items 1, 2, 4, 5, 7, 9, and 10). In the CC to symptom perception, we hypothesized 2 factors: symptom monitoring (items 11–19) and symptom recognition (items 20 and 21). Finally, in the CC to self-care management scale, we hypothesized 2 factors: recommended behaviors (items 22–24 and 26) and problem-solving behaviors (items 25 and 27–29).

In CFA, because several items were not normally distributed, we used the robust maximum likelihood method for parameter estimation. To examine the model fit of each scale, the following fit indices were used: the CFI, the Tucker-Lewis Index (TLI), the RMSEA, and the standardized root mean square residual (SRMR).23–25 Comparative fit index and TLI values of 0.90 to 0.95 or, better, greater than 0.95 indicate supportive fit.26 Root mean square error of approximation values of 0.05 to 0.08 or, better, less than or equal to 0.05 indicate a well-fitting model.27 Standardized root mean square residual values of 0.08 or less indicate a good fit. We also used the χ2 statistic, but this was not used in interpreting model fit because it is sensitive to sample size. Once the definitive model was identified for each scale, we tested the internal consistency reliability of each scale with Cronbach α and the global reliability index for multidimensional scales.28 Both estimates should have a value of 0.70 or greater. In addition, we computed the item-total corrected correlations, which should have a value of 0.30 or greater.29

In the fourth step, we tested concurrent validity of the CC-SCHFI 2. Finally, in the fifth step, we tested CC-SCHFI 2 test-retest reliability with intraclass correlation coefficient. Test-retest reliability was performed on 120 caregivers who completed the CC-SCHFI 2 at baseline and again after 2 weeks. Data were analyzed using Mplus version 8.2 (Muthén & Muthén, 1998) and IBM SPSS Statistics version 22.

Results

Sample Description

In total, 277 caregivers and 277 patients with HF were enrolled in the study. The average age of HF caregivers was 52.7 years (SD, 14.9), and most were female (70.4%); approximately 68% of caregivers were married, and 60% were educated at a high school or university level. A large proportion of caregivers (46.9%) were adult children, and more than half (55.6%) did not live with the patient with HF (Table 1).

TABLE 1
TABLE 1:
Sociodemographic Characteristics of Caregivers and Patients With Heart Failure (N = 277)

The sociodemographic characteristics of patients with HF are reported in Table 1. On average, patients with HF were 75.4 years old (SD, 10.8), with a slight prevalence of men (54.9%). The majority were married, and 74% were educated only at an elementary or middle school level. Most patients with HF (84.8%) were retired. Most were in NYHA classes II (38.3%) and III (32.5%) (Table 2). The most common HF etiology was ischemic (37.9%). Common comorbidities were hypertension (75.8%), previous myocardial infarction (38.3%), and atrial fibrillation (32.9%). The mean (SD) HF duration was 51.3 (50.2) months.

TABLE 2
TABLE 2:
Clinical Characteristics of Patients With Heart Failure (N = 277)

Item Descriptive Analysis and Scales' Scores

Table 3 illustrates the descriptive analysis of the CC-SCHFI 2 items. Regarding the CC to self-care maintenance scale, the item with the highest score (mean [SD], 4.36 [0.99]) was item 5 (“take prescribed medicines without missing a dose”), whereas the item with the lowest score (mean [SD], 3.18 [1.53]) was item 9 (“use a system or method to help remember to take medicines”). The CC to symptom perception scale item with the highest score (mean [SD], 4.24 [1.02]) was item 15 (“ask the healthcare provider how he or she is doing”), whereas the item with the lowest score (mean [SD], 2.49 [1.50]) was item 21 (“how quickly did you know that the symptom was due to heart failure”). The CC to self-care management scale item with the highest score (mean [SD], 4.35 [0.95]) was item 25 (“call the healthcare provider for guidance”); the item with the lowest score (mean [SD], 2.58 [1.45]) was item 29 (“Think of what you did the last time the person you care for had symptoms…Did the treatment you used make him or her feel better”). Several items of the 3 scales were not normally distributed, with skewness and kurtosis greater than 1.

TABLE 3
TABLE 3:
Caregiver Contributions to Self-Care of Heart Failure Index 2 Item Descriptive Analysis

The CC to self-care maintenance, CC to symptom perception, and CC to self-care management scales had a mean (SD) score of 70.02 (19.90), 67.01 (20.37), and 67.57 (19.67), respectively. Caregivers with adequate contributions to self-care in self-care maintenance, symptom perception, and self-care management were 57.8%, 40.9%, and 44% of the sample, respectively. The CACHS scales of self-care maintenance, self-care monitoring, and self-care management had mean (SD) scores of 62.70 (16.09), 71.53 (19.65), and 78.18 (18.78), respectively. Finally, the SCHFI v.7.2 scales of self-care maintenance, symptom perception, and self-care management had mean (SD) scores of 59.18 (17.81), 57.17 (18.41), and 59.61 (21.09), respectively.

Psychometric Analysis of the Caregiver Contributions to Self-Care Maintenance Scale

Dimensionality

Confirmatory factor analysis testing the 2-factor structure of the CC to self-care maintenance scale, with the dietary behaviors (items 3, 6, and 8) and consulting behaviors (items 1, 2, 4, 5, 7, 9, and 10) factors, initially had unsatisfactory fit indices: χ2(34) = 81.03; P < .001; CFI, 0.90; TLI, 0.87; RMSEA, 0.07 (90% confidence interval [CI], 0.051–0.09; P(RMSEA ≤ 0.05) = .045); and SRMR, 0.068. An inspection of the modification indices revealed a cross-loading of item 3 (“eat a low salt diet”) on the consulting behavior factor needed to be specified. When the CFA was rerun with item 3 loading on both factors, the model had an adequate fit to the data (Figure 1): χ2(33) = 57.06; P < .01; CFI, 0.95; TLI, 0.93; RMSEA, 0.051 (90% CI, 0.027–0.073; P(RMSEA ≤ 0.05) = .443); and SRMR, 0.05. All factor loadings were significant and high except for item 1 (“get some exercise”), which had a low but significant loading of 0.147 (Figure 1).

FIGURE 1
FIGURE 1:
Confirmatory factor analysis of the caregiver contributions to self-care maintenance scale. The numbers near the 1-headed arrows are factor loading coefficients; the numbers near the 2-headed arrows are correlation coefficients; the numbers aiming to the items through a 1-headed arrow are residual variances. Abbreviation: i, item.

Scale Internal Consistency Reliability and Item-Total Correlation

When the Cronbach α coefficient was computed on the entire scale, an adequate coefficient of .83 was obtained. However, α assumes that the items satisfy a unidimensional structure. Knowing that there are 2 dimensions represented in this scale, we used a reliability coefficient that takes multidimensionality into account—the global reliability index for multidimensional scales. This coefficient was 0.79. All the items had adequate discrimination, with an item-total corrected correlation of greater than 0.30.

Psychometric Analysis of the Caregiver Contributions to Symptom Perception Scale

Dimensionality

The CC to symptom perception scale was hypothesized to have 2 dimensions: symptom monitoring (items 11–19) and symptom recognition (items 20 and 21). When this 2-factor model was tested, the model fit was adequate: χ2(45) = 98.96; P < .001; CFI, 0.93; TLI, 0.91; RMSEA, 0.065 (90% CI, 0.048–0.083; P(RMSEA ≤ 0.05) = .071); and SRMR, 0.052. However, inspection of the modification indices suggested an estimation of the error covariances between item 11 (“monitor your weight daily”) and item 19 (“keep a record of symptoms”). When the model was respecified to include this error covariance, model fit improved (Figure 2): χ2(44) = 86.65; P < .001; CFI, 0.94; TLI, 0.93; RMSEA, 0.059 (90% CI, 0.040–0.077; P(RMSEA ≤ 0.05) = .201); and SRMR, 0.047. All factor loadings were significant, and the factor correlation was 0.499 (Figure 2).

FIGURE 2
FIGURE 2:
Confirmatory factor analysis of the caregiver contributions to symptom perception scale. The numbers near the 1-headed arrows are factor loading coefficients; the numbers near the 2-headed arrows are correlation coefficients; the numbers aiming to the items through a 1-headed arrow are residual variances. Abbreviation: i, item.

Scale Internal Consistency Reliability and Item-Total Correlation

When the internal consistency reliability analysis was performed on the whole sample, the Cronbach α coefficient of the CC to symptom perception scale was .81. Knowing that the factorial structure of this scale is bidimensional, we recalculated reliability using the global reliability index for multidimensional scales. This coefficient was 0.86. All items had adequate discrimination, with an item-total corrected correlation of greater than 0.30.

Psychometric Analysis of the Caregiver Contributions to Self-Care Management Scale

Dimensionality

The 8 items measuring CC to self-care management scale were hypothesized to reflect 2 dimensions: recommended behaviors (items 22–24 and 26) and problem-solving behaviors (items 25 and 27–29). When these 2 dimensions were specified at CFA, the resulting fit indices were unsupportive: χ2(19) = 140.1; P < .001; CFI, 0.76; TLI, 0.64; RMSEA, 0.154 (90% CI, 0.131–0.178; P(RMSEA ≤ 0.05) < .001); and SRMR, 0.118. An inspection of the modification indices revealed that item 29 was a much better marker of the recommended behavior factor and item 26 was a much better marker of the problem-solving factor. After switching the 2 items across factors, the respecified model had an adequate fit to the data (Figure 3): χ2(19) = 45.63; P < .001; CFI, 0.95; TLI, 0.93; RMSEA, 0.071 (90% CI, 0.045–0.097; P(RMSEA ≤ 0.05) = .091); and SRMR, 0.053. All factor loadings were significant, and the factor correlation was 0.43 (Figure 3).

FIGURE 3
FIGURE 3:
Confirmatory factor analysis of the caregiver contributions to self-care management scale. The numbers near the 1-headed arrows are factor loading coefficients; the numbers near the 2-headed arrows are correlation coefficients; the numbers aiming to the items through a 1-headed arrow are residual variances. Abbreviation: i, item.

Scale Internal Consistency Reliability and Item-Total Correlation

The internal consistency reliability analysis of the CC to self-care management scale, when tested with Cronbach α, was .81. When reliability was retested with the global reliability index for multidimensional scales, the coefficient was 0.85. All items had adequate discrimination, with an item-total corrected correlation of greater than 0.30.

Concurrent Validity and Test-Retest Reliability of the Caregiver Contributions to Self-Care of Heart Failure Index 2

Table 4 reports the correlations between the CC-SCHFI 2, the CACHS, and the SCHFI v.7.2 scale scores. The CC-SCHFI 2 scores were significantly correlated with both the CACHS and the SCHFI v.7.2 scale scores. In addition, considering the CC-SCHFI 2 cutoff for CC adequacy, caregivers with a score of greater than 70 had a significantly higher scores at the CACHS than those who were not adequate (Table 5). Test-retest reliability of the CC-SCHFI 2 resulted in an intraclass correlation coefficients of 0.91, 0.72, and 0.91 for the CC to self-care maintenance, CC to symptom perception, and CC to self-care management scales, respectively.

TABLE 4
TABLE 4:
Concurrent Validity of the Caregiver Contributions to Self-Care of Heart Failure Index
TABLE 5
TABLE 5:
Caregiver Contribution to Heart Failure Self-Care Scale Scores by Caregiver Contributions to Self-care Adequacy

Discussion

Our analysis showed that the CC-SCHFI 2 is a valid and reliable measure of CC to HF self-care. Because caregivers have a key role in caring for patients affected by HF and previous studies have shown that CC to HF self-care can improve patient outcomes, it is important to have a valid and reliable instrument to measure these contributions. The CC-SCHFI 2 advances the characteristics of the older version of the CC-SCHFI30 in several ways. First, the CC-SCHFI 2 is theoretically based because it reflects the Situation-Specific Theory of Caregiver Contributions to Heart Failure Self-Care.19 Second, the CC-SCHFI 2 expands on the original CC to self-care maintenance by including additional behaviors (eg, ask the healthcare provider about prescribed medicines). Third, the CC-SCHFI 2 investigates CC to symptom perception, which was not considered in the original CC-SCHFI. Fourth, the CC to self-care management scale considers the support of family member and friend caregivers in responding to an HF exacerbation. These characteristics make the CC-SCHFI 2 stronger than the previous version. Interestingly, as we found for the SCHFI, the CC-SCHFI 2 reflects the factorial structure of the SCHFI v.7.2, which provides evidence that patients and caregivers share the same construct of self-care.

Regarding the CC to self-care maintenance scale, we found 2 dimensions within this scale: dietary behaviors and consulting behaviors. Interestingly, item 3, asking how often caregivers recommend that patients eat a low-salt diet, had a cross-loading with the consulting behavior factor. This was not unexpected because this same item in the original CC-SCHFI had a cross-loading with the factor that we named “medical treatment adherence.” Our interpretation of this cross-loading is that, in the Italian culture, physicians recommend that patients with HF reduce salt in the diet. The low loading of item 2 (“get some exercise”) was another expected finding, because caregivers in Italy rarely advise patients to perform physical activity,31 probably because they are afraid that activity can harm the patient.

In the CC to symptom perception scale, we found 2 factors: symptom monitoring and symptom perception. The covariance that we allowed after inspection of the modification indices (covariance between residuals of item 11 [“monitor weight daily”] and item 19 [“keep a record of symptoms”]) was logical because caregivers are often taught by providers to keep a record of patient weights and other signs and symptoms. According to Fornell32 and Bagozzi,33 allowing measurement errors to correlate in CFA is reasonable when it is plausible, from a theoretical and methodological point of view, and when specification of covariance between measurement errors does not alter the estimation of the other parameters. This was our situation.

Regarding the CC to self-care management scale, we identified 2 dimensions: recommended behaviors and problem-solving behaviors. The hypothesized model that reflected the patient model (SCHFI 7.2) did not fit the data well. The misfit was due to 2 items that were better markers of the other dimension. Specifically, item 29 (“think of what you did the last time the person you care for had symptoms: Did the treatment you used make him or her feel better”), originally specified in the dimension “problem-solving behaviors,” was better in the “recommended behaviors”; item 25 (“call the healthcare provider for guidance”), originally specified in the dimension “recommended behaviors,” was better in the “problem-solving behaviors” factor instead. These differences between caregivers and patients in the self-care management scale may reflect a different approach to dealing with signs and symptoms of HF. It seems that, regarding recommended behaviors, patients limit salt in the diet, reduce fluid intake, take a medicine, and call the provider, whereas caregivers recommend that patients limit salt in the diet, reduce fluid intake, take a medicine, and then evaluate whether signs and symptoms have been reduced. Regarding problem-solving behaviors, when signs and symptoms occur, patients consult family members and friends, try to figure out the reasons for the symptoms, limit their activity until they feel better, and then evaluate whether this problem solving worked. Caregivers do almost the same sequence of behaviors, but in the end, they call the provider to get guidance.

Each scale had good internal consistency reliability. However, as we have already demonstrated in the case of the SCHFI v.6.2,34 because the construct of self-care in the 3 scales is multidimensional, Cronbach α is not the best measure of reliability.35 However, we observed a convergence between the 2 reliability estimates, which gives further strength to the reliability of the CC-SCHFI 2.

In this study, we tested the concurrent validity of the CC-SCHFI 2 with the SCHFI v.7.2 and the CACHS. The significant and moderate correlations between the CC-SCHFI 2 and the SCHFI v.7.2 scales were expected because HF patient self-care and CC to HF self-care are correlated. Regarding the 3 CACHS dimensions, because both instruments measure CC to HF self-care, we expected stronger correlations. Instead, these correlations were only moderate. The CC-SCHFI 2 and the CACHS were developed with 2 different approaches. As reported earlier, the CC-SCHFI 2 was developed by modifying the SCHFI v.7.2 items into a format appropriate for caregivers. The items in the SCHFI v.7.2 represent evidence-based behaviors that patients should adopt to deal with HF. The CACHS was developed with semistructured interviews conducted with informal HF caregivers. These interviews were guided by the Middle Range Theory of Self-care of Chronic Illness and were conducted to explore which behaviors caregivers adopt to help patients maintain HF stability (self-care maintenance), monitor their conditions (self-care monitoring), and respond to HF exacerbations (self-care management). Interestingly, whereas some items are similar in the 2 instruments (eg, those investigating exercise or watching for changes in breathing), others are completely different (eg, keeping a record of symptoms is present only in the CC-SCHFI 2, and watching for changes in sleeping patterns is only present in the CACHS). We believe that a combination of the 2 instruments may improve the measurement of CC to HF self-care in future research and may enrich our understanding of the role of caregivers in HF self-care. For these 2 purposes, the Situation-Specific Theory of Caregiver Contributions to Heart Failure Self-Care19 may be useful because the 3 theoretical dimensions of CC to self-care maintenance, CC to symptom monitoring and perception, and CC to self-care management are measured by both the CC-SCHFI 2 and the CACHS.

Regarding test-retest reliability, the high values of the intraclass correlation coefficients illustrate the stability of the 3 CC-SCHFI 2 scales across time. This characteristic is important in situations where the CC-SCHFI 2 is used to measure the efficacy of an intervention to improve CC to HF self-care.

Users of the CC-SCHFI will note that the caregiver confidence scale is not included in the CC-SCHFI 2. As with the SCHFI v.7.2, we excluded this scale because caregiver confidence, although important in improving CC to self-care, is not self-care per se. We strongly recommend measuring confidence (self-efficacy to contribute to self-care) and have developed a generic instrument to measure caregiver confidence to self-care. This generic instrument can be used for any variety of chronic conditions, not only HF. Its psychometric characteristics will be published soon.

This study has several limitations. We used a convenience sample from only 1 European country; consequently, our results should be considered with caution in other cultures and countries. It would be advisable to test the CC-SCHFI 2 also in other cultures and countries to enrich our understanding of CC to HF self-care especially if authors of future studies test the measurement invariance of the CC-SCHFI 2. Another limitation is that we excluded patients with important cognitive impairment, so generalization of our finding to this specific population should be done with caution.

This study has several clinical and scientific implications. From a clinical perspective, the CC-SCHFI 2 could allow a better and comprehensive assessment of CC to HF self-care including also CC to symptom perception, which was missing from the original CC-SCHFI. Caregiver role in symptom monitoring and perception is important because changes in signs and symptoms may be an alert of HF decompensation. From a scientific perspective, the use of the CC-SCHFI 2 would allow a deeper understanding of CC to HF self-care and a further development of the Situation-Specific Theory of Caregiver Contributions to Heart Failure Self-Care, which is still in its infancy. In fact, the complex relationships among the components of the theory—contributors, the process of CC to HF self-care, and its outcomes—are not well known yet. For example, in a previous study that we conducted,36 CC to HF self-care maintenance reduced patient clinical event risks (mortality, hospitalizations, and access to emergency department), but CC to self-care management did the contrary. From a clinical and scientific perspective, the combined use of the SCHFI v.7.2 and the CC-SCHFI 2 with patients with HF and their caregivers would allow a comprehensive assessment of the self-care process performed by the dyad.

Conclusion

In conclusion, this study demonstrates that the CC-SCHFI 2 is a psychometrically sound instrument with proven validity and reliability that can be used in clinical practice and research to assess CC to HF self-care. A combined use of the CC-SCHFI with the CACHS would allow a better understanding of CC to HF self-care, and a combined use of the CC-SCHFI 2 with the SCHFI v.7.2 would facilitate dyadic studies on the self-care process.

What’s New and Important
  • The CC-SCHFI 2 is a theoretically driven instrument that measures CC to self-care in HF.
  • The CC-SCHFI 2 evaluates CC with 3 scales: CC to self-care maintenance, assessing CC in maintaining HF stability; CC to symptom perception, assessing CC in symptom monitoring and perception; and CC to self-care management, which evaluates CC in responding to signs and symptoms of HF exacerbations.
  • The CC-SCHFI 2 is valid and reliable and can be used in clinical practice and in research.

REFERENCES

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Keywords:

caregivers; heart failure; psychometrics; reliability; self-care; validity

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