Confirmatory Factor Analysis
The 3-factor structure for the CRI was tested using confirmatory factor analysis using the maximum likelihood estimation method. Outcome anxiety, process anxiety, and autonomy were entered into the model as latent variables; each was connected to their corresponding 6-component CRI items that were entered as observed variables. This model converged but, as typically expected with large samples,34 produced a poor global χ2 test outcome (χ2132 = 426, P < .001). Other accepted goodness-of-fit estimates34 for the model were adequate (CMin/df = 3.2, root-mean-square error of approximation = 0.073 with 90% confidence interval, 0.065–0.081, PClose < .001).
In an attempt to strengthen the fit of the model, a 2-factor model was created by repeating the factor analysis. This simplest 2-factor structure with no cross-loading of items between components was found using Oblimin rotation with Kaiser normalization (factor 1, items 45, 46, 54, 40, 37, 41, 51, and 31 with α = .825 and rSB = 0.811; factor 2, items 16, 15, 14, 23, 17, 34, 53, and 43 with α = .669 and rSB = 0.628). The 2-factor structure was also tested using confirmatory factor analysis, but this did not improve the goodness of fit of the model (χ2103 = 321, P < .001; CMin/df = 3.1, root-mean-square error of approximation = 0.071 with 90% confidence interval, 0.062–0.080, PClose < .001). Consequently, the original 3-factor CRI structure was accepted; the confirmatory factor analysis model with standardized regression weights (factor loadings) is presented in the Figure.
Multiple Regression Analysis of the Cardiac Rehabilitation Inventory
The total amount of variance (adjusted r2) in CR intentions that could be explained by the revised CRI was 57.5% (r2 = 0.575; F3, 414 = 189, P < .0001). Outcome anxiety accounted for 71.6% of variance in CR intentions (adjusted r2 = 0.716, β = 1.0, t = 20.3, P < .0001), process anxiety accounted for 3.1% of the variance (adjusted r2 = 0.031, β = .04, t = 0.9, P = .369), and autonomy accounted for 11.0% of the variance (adjusted r2 = 0.110, β = .17, t = 3.4, P = .001).
Demographic Categories, Cardiac Rehabilitation Inventory Outcomes, and Cardiac Rehabilitation Intentions
Respondent Cohort Comparisons
Between the UK and NZ cohorts, there were no differences in the proportion of age categories (χ24 = 4.2, P = .373) or the proportion of men and women (χ21 = 0.6, P = .455). However, there were differences between the UK and NZ cohorts in the representation of ethnic groups (χ25 = 11.6, P = .04), educational achievement (χ24 = 22.3, P < .001), employment status (χ24 = 124.1, P < .001), access to transport (χ24 = 16.2, P = .003), and Transtheoretical Model stage of change (χ24 = 42.4, P < .001). Frequency and percentage data for each demographic category are presented in Table 3.
Demographic Category Comparisons
Differences for outcome anxiety were found between the United Kingdom and New Zealand (t416 = 3.5, P < .001) and between age groups (F4, 392 = 3.6, P = .007), access to transport categories (F4, 393 = 4.1, P = .003), and stage of change categories (F4, 417 = 20.6, P < .001). For process anxiety, differences were found between age groups (F4, 392 = 5.2, P < .001), ethnic groups (F5, 394 = 3.5, P = .004), and access to transport categories (F4, 393 = 5.8, P < .001). Autonomy differences were found between the UK and NZ cohort (t416 = −2.2, P = .03), age groups (F4, 392 = 5.1, P < .001), and stage of change categories (F4, 417 = 2.9, P = .021). Differences in CR intentions were found between age groups (F4, 392 = 4.5, P = .002), access to transport categories (F4, 393 = 2.5, P = .041) and, as expected, strongly according to stage of change (F4, 417 = 57.3, P < .001). There were no other CRI outcome or CR intention differences among demographic groups. All CRI and intention outcomes, with Tukey post hoc comparisons, are presented in Table 3.
Outcome anxiety, process anxiety, and autonomy were identified as important constructs of CR engagement and were found to be a good predictor of CR intentions. We labeled the first CRI subscale outcome anxiety because the items focus on beliefs about experiencing negative outcomes either as a direct or an indirect consequence of CR. We would define outcome anxiety in this context as apprehensive feelings, thoughts, or dispositions about the consequences of participating in CR. Interestingly, this construct is similar to the feelings of fear and anxiety that some patients attribute to limiting their physical activity.35 Process anxiety differs in that it represents feelings, thoughts, and dispositions of apprehension that are specifically associated with the CR intervention itself. This CRI subscale perhaps reflects some of the barriers to participating in CR that have been identified by others, such as low self-efficacy,36 worries about exercising in front of others,20,37,38 and kinesiopohbia (fear of movement).39 The final CRI subscale, autonomy, focuses on the agency patients feel to be able to improve their prognosis by developing a better understanding of their condition, participating in CR, and implementing other lifestyle changes. Autonomy is perhaps an indication of participants’ proclivity to take an active role and responsibility for their rehabilitation, which, as indicated in a previous study,24 is associated with a sense of control. A recent systematic review revealed that patients who view their condition as symptomatic, as controllable, and with severe consequences and who feel that they understand their condition are more likely to attend CR.40
Outcome anxiety accounted for just under three-quarters of the variance in CR intentions. We also found that CR attendees (actors and maintainers) had significantly greater outcome anxiety compared with nonattenders (precontemplators, contemplators, and preparers). Clearly, those not attending CR have no reason to be anxious about an outcome of something they are not doing, but what our results do highlight is than during the initial period of CR uptake, attendees may experience an increase in anxiety about the effects of CR on their condition and health. Individual support might then focus on reducing outcome anxiety because dropout rate is greater among those with elevated levels of anxiety.41
Process anxiety was a poor predictor of CR intentions, but respondents younger than 60 years were found to be less anxious about CR processes than were older respondents. Given that age is a known barrier to CR uptake and adherence,19–22 more effective age group support might focus on reducing process anxiety. Examples of how this might be achieved include varying the induction process, refining age-appropriate activities, or using peer buddies or CR mentors. These or other similar methods might also help increase feelings of autonomy, which, somewhat unsurprisingly, were found to be lowest among those older than 70 years.
Autonomy, measured using the CRI, accounted for only 11% of CR intentions but was lowest among the precontemplators. Most CR guidelines focus on support for those already attending CR, but much could be done to better understand how to support and encourage nonattenders, especially given the recent added importance placed on improving uptake and adherence.42 Although it is not possible to say how strong an influence low autonomy has on the decision not to participate in CR, it might be that efforts to support self-efficacy, locus of control, and autonomy could help such individuals move out of a precontemplative stage.
Practical Cardiac Rehabilitation Inventory Recommendations to Support Individual Patient Needs
By convention, CR is structured according to patient clinical status or risk stratification,5 and it is less common to provide further tailoring around psychosocial factors despite substantial evidence of their importance to uptake and adherence.10,11,13,16–20 Tailoring CR according to individual preference, choice, and psychosocial factors has been advocated in a variety of studies, reviews, and guidelines.3,4,7,18–20,24,35,43,44 The remainder of this discussion will focus on how the CRI can be used to determine individual patient needs and some of the practical steps that can be taken to accommodate those needs.
Administering the CRI to CR attendees should be carried out at the earliest opportunity, once it is known they will be referred for CR and regardless of whether the person intends to uptake CR or not. As previously discussed, it is especially important to engage with precontemplators, and the CRI will provide information that can help in supporting the particular needs of this group of patients. First, it is important to gather early information upon which individual needs can be accommodated in any subsequent CR plan. Second, the process of administering and discussing CRI outcomes provides an opportunity for collaborative interaction with the practitioner, which, in itself, should help to develop genuine feelings of agency, confidence, and individuality among attendees. Further detailed guidelines on how to interpret CRI responses are provided in Supplement 2 (http://repository.essex.ac.uk/id/eprint/12463).
Supporting High Outcome Anxiety, High Process Anxiety, or Low Autonomy
After completing the CRI, each respondent will have profile of scores for the 3 components. Generally speaking, lower outcome anxiety scores, lower process anxiety scores, and higher autonomy scores are good. Respondents could score poorly in an individual component or any combination of components. The extent of their needs will be broadly proportionate to both the number of components that they score poorly in as well as the magnitude of each score. Once the CRI profile for a respondent has been established, attempts should be made to negotiate a CR program with them that corresponds with their individual needs. This kind of accommodation and intervention should have a preservative influence on CR intentions and, as suggested in other studies, engagement and adherence behavior.11–13,16–20,37,38,40
Those with high outcome anxiety may be reluctant to persist with CR because of feelings of vulnerability and an irrational fear that CR will exacerbate their prognosis. As noted earlier, those attending CR have high outcome anxiety than nonattendees do; therefore, once an individual agrees to attend CR, help should be provided to prepare them for the increase in anxiety that they will most likely experience. Once they have started, support should focus on reducing outcome anxiety. It may be advantageous for such individuals to begin CR by attending education sessions before any involvement in exercise in an attempt to redress irrational beliefs and assuage their anxiety. Those with high process anxiety may feel unfamiliar, uncomfortable, or intimidated by the group or exercise environment associated with CR, and as we have reported, older individuals appear to be particularly prone to these feelings. Such individuals may benefit from having a progressive introduction to CR that perhaps first involves watching an exercise session, meeting other CR participants in a nonexercising context, and having a mentor who is an existing participant. It may also be beneficial to take into consideration their individual preferences with respect to types of exercise and gender groups. Those who have low autonomy scores are likely to have a high external locus of control, resulting in greater dependency on others and passive engagement in CR. In some instances, it will be possible to address low autonomy by simply helping with the practical matters, such as CR travel, timing, location, and subsidization. For other individuals, a lack of autonomy might be improved by involving them in decision-making processes about their CR, offering them a choice, and then getting them to reflect on the outcomes of their choices. These suggestions of how to address high anxiety and low autonomy are by no means exhaustive but rather examples of how practitioners might use CRI information to provide appropriate levels of individual support. The overarching principle is to tailor support according to individual need, and the CRI can provide some of the information needed in this process.
There are several limitations to the CRI development work presented in this article. First is the need for more extensive validity testing against actual attendance and engagement with CR. Although we have shown that CRI measurements differ between respondents at different stages of change, what is now needed is to perform a large-scale validation study to assess whether the 3 CRI constructs have any predictive, discriminant, or concurrent validity against actual CR engagement. A further study is also needed to assess whether interventions involving CRI informed tailored support improves the uptake and ongoing engagement with CR. Another limitation, evident in Table 3, is that certain demographic groups were underrepresented in our study. In particular, we would like to see better representation of women, nonwhite ethnic groups, and pre-retirement age groups in further CRI studies. In addition, the inclusion of other demographic information in future studies would also improve the validity of the CRI, such as marital status, primary CHD diagnosis, and history of CHD.
We have developed the CRI, which can be used to identify individual needs of individual CR patients with respect to 3 dimensions of outcome anxiety, process anxiety, and autonomy. The CRI and its subscales were found to be reliable. Differences in CRI outcomes were found between those at different Transtheoretical Model stages of change, helping to validate the scale. Although we recognize that further validity testing is needed, the CRI is a useful instrument that can furnish CR practitioners with the information they need to tailor the CR environment and program according to individual needs. The CRI has heuristic potential in terms of future implementation and could impact on meaningful client outcomes and future CHD preventative strategies.
What’s New and Important
- Outcome anxiety, process anxiety, and autonomy are useful constructs in attempting to understand the individual needs of community-based CR patients.
- The CRI is an evidence-based short questionnaire that can help CR practitioners to identify the individual needs of their patients.
- The CRI has heuristic potential in terms of future implementation and could impact on meaningful client outcomes and future coronary heart disease preventative strategies.
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Keywords:Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved
cardiovascular diseases; exercise; questionnaires; rehabilitation