ORIGINAL RESEARCH: EMPIRICAL RESEARCH – QUANTITATIVE
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Effects of a transtheoretical model–based exercise stage–matched intervention on exercise behaviour and quality of life in patients with coronary heart disease: a randomized controlled trial
Accepted for publication 24 May 2014
Correspondence to S-C. Ho: e-mail: [email protected]
Z H U L - X . , H O S - C . , S I T J . W . H . & H E H - G . ( 2 0 1 4 ) Effects of a transtheoretical model–based exercise stage–matched intervention on exercise behaviour and quality of life in patients with coronary heart disease: a randomized controlled trial. Journal of Advanced Nursing 00(0), 000–000. doi: 10.1111/jan.12469
Abstract
Aim. To examine the effects of a transtheoretical model–based exercise stage– matched intervention on exercise behaviour and quality of life in patients with coronary heart disease. Background. Exercise-based cardiac rehabilitation has been shown to be beneficial to quality of life for patients with coronary heart disease. However, patients’ participation in rehabilitation programmes is poor. The transtheoretical model has been found to be an effective model for changing exercise behaviour in various populations; however, few studies have examined its effects on patients with coronary heart disease. Design. Randomized controlled trial. Methods. A total of 196 eligible patients were recruited from September 2009– January 2011 and randomly allocated to the control, ‘sham’ or experimental group. Outcome measures including exercise behaviour and quality of life were assessed at baseline, immediate postintervention and at 3- and 6-month followups. The chi-square test and Kruskal–Wallis test were used to analyse data. Results. Findings showed that, compared with the other two groups, patients in the Experimental group were more likely to be at the action and maintenance stages according to the exercise stages of change scale. They also showed longer moderateintensity exercise duration as recorded by a logbook and significantly greater improvements in physical functioning, general health, vitality, social functioning, mental health, physical component summary and mental component summary of SF-36 after the 8-week intervention and up to 3- and 6-month follow-ups. Conclusion. The transtheoretical model–based exercise stage–matched intervention has positive effects on exercise behaviour and quality of life in patients with coronary heart disease.
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Li-Xia Zhu PhD RN PhD Graduate, Post-doctoral Researcher School of Nursing, The Hong Kong Polytechnic University, Hong Kong, China Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Li-Xia Zhu, Shuk-Ching Ho, Janet Wing Hung Sit & Hong-Gu He
Shuk-Ching Ho PhD RN Assistant Professor School of Nursing, The Hong Kong Polytechnic University, Hong Kong, China
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Janet Wing Hung Sit PhD RN Associate Professor The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong, China
Hong-Gu He MD PhD RN Assistant Professor Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Keywords: coronary heart disease, exercise behaviour, exercise stage–matched intervention, nursing, quality of life, transtheoretical model
© 2014 John Wiley & Sons Ltd
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L-X. Zhu et al.
Patients with coronary heart disease have poor quality of life and regular exercise or exercise-based cardiac rehabilitation has been shown to be beneficial for improving their quality of life. Patients’ participation in, and adherence to, exercise programmes is poor. The transtheoretical model has been found to be an effective model for changing exercise behaviour; however, few studies have examined the effects of such interventions on
patients scored lower in most domains of SF-36 within a period of 25 years following myocardial infarction (Worcester et al. 2007, Zhang et al. 2011). Exercise-based cardiac rehabilitation has been shown to benefit CHD patients’ QoL (Heran et al. 2011). However, participation in, and adherence to, exercise-based cardiac rehabilitation programmes is poor (Suaya et al. 2007, van Engen-Verheul et al. 2013). Thus, improving the uptake of, and adherence to, exercise-based cardiac rehabilitation programmes – which in turn improve CHD patients’ QoL – is a global concern.
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Why is this research or review needed?
patients with coronary heart disease.
Patients who received exercise stage–matched intervention
were more likely to engage in regular exercise (namely, at the action and maintenance stages) and demonstrated
longer duration of moderate-intensity exercise (minutes/ week) than those who received conventional care and general patient education after the 8-week intervention and up to their 6-month follow-up.
Patients who received exercise stage–matched intervention
showed greater improvements in quality of life than those
who received conventional care and general patient educa-
How should the findings be used to influence policy/ practice/research/education?
To provide evidence that the transtheoretical model–based, exercise stage–matched intervention has positive effects on
exercise behaviour and quality of life in patients with coronary heart disease.
It is necessary and important to provide patients with cor-
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onary heart disease with a structured, transtheoretical model–based patient education programme.
Introduction
Coronary heart disease (CHD) is the leading cause of death and disability among adults worldwide and has become the third leading cause of death among Chinese adults (Health Statistics Information Centre of the Ministry of Health PRC 2012). Previous studies have shown that patients with CHD have poor quality of life (QoL) (Bengtsson et al. 2004, Brink et al. 2005, Kristofferzon et al. 2005). Compared with an age- and sex-matched healthy population, CHD
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Exercise training alone or exercise-based cardiac rehabilitation has been shown to be beneficial for improving the QoL of patients with heart disease (Heran et al. 2011). However, patients’ participation in, and adherence to, exercise-based cardiac rehabilitation programmes has been discouraging globally. Previous studies have shown that only 26–835% of CHD patients participate in at least one session of a formal cardiac rehabilitation programme (Goto et al. 2007, Suaya et al. 2007, Bethell et al. 2008, Dressler & Lewin 2013, van Engen-Verheul et al. 2013), with the participation rate being lowest in patients with stable angina pectoris (van Engen-Verheul et al. 2013). Of those who participated in cardiac rehabilitation programmes, the dropout rates reached approximately 50% during the first 6 months of the programmes (Sanderson & Bittner 2005, Sarrafzadegan et al. 2007). Thus, it is imperative to call for a more patient-centred approach in tailoring interventions to improve the uptake of, and adherence to, exercise-based cardiac rehabilitation programmes, which in turn could improve CHD patients’ QoL. Previous studies have illustrated that the transtheoretical model (TTM) (Prochaska & DiClemente 1983) is effective for changing exercise behaviour in various populations from young adults (Kim 2008, Huang et al. 2009) to older people (M€ arki et al. 2006, Greaney et al. 2008). Unfortunately, few studies have examined the effects of TTMbased interventions on changes in exercise behaviour in cardiac patients (Zhu et al. 2013). Our literature review found that only four studies have used the TTM to motivate cardiac patients to engage in or maintain regular exercise. These four studies have shown inconsistent conclusions about adherence to regular exercise and all of them recruited participants immediately after completion of a formal cardiac rehabilitation programme (Hughes et al. 2002, 2007, Naser et al. 2008, Pinto et al. 2011). In addi-
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tion after the 8-week intervention and up to their 6-month follow-up.
Background
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What are the key findings?
© 2014 John Wiley & Sons Ltd
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barriers of changing their behaviour, which vary across stages of change. The TTM offers a promising approach to integrating the stages and processes of change. Based on the stages of change, researchers can develop stage-matched interventions, which refer to interventions that match the individual’s current stage of behavioural change (Prochaska & DiClemente 1983). Thus, ESMI refers to the delivery of strategies and techniques (processes of change) that are matched to the individual’s current stage of readiness for change in his/her exercise behaviours (Kim 2008). For patients at different exercise stages of change, different goals are set and different processes of change (strategies and techniques) are used to help them move on to a more advanced stage. Subsequently, ESMI improves individuals’ exercise stages of change, exercise self-efficacy and exercise decisional balance (Kim 2008, Huang et al. 2009). Individuals with higher exercise self-efficacy have more confidence about changing their exercise behaviour, which results in a more positive shift in exercise stages of change. When the benefits of changing one’s exercise behaviour increase to the same level as the barriers, individuals start to take action to change their exercise behaviour. When the benefits outweigh the barriers, individuals are more likely to successfully adhere to regular exercise, moving on to the action and maintenance stages. The result is motivation [a force that initiates, guides and maintains a goal-oriented behaviour (Cherry 2011)] to engage in regular exercise and increase exercise duration, which is beneficial for improving CHD patients’ QoL (Heran et al. 2011). A theoretical framework for the ESMI used in this study is shown in Figure 1.
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tion, few studies have examined the effects of the TTMbased exercise interventions on QoL among CHD patients as a result of changes in exercise behaviour. Few studies have demonstrated inconsistent conclusions in their effect on QoL. Two studies showed that TTM-based exercise interventions resulted in significantly greater improvement in QoL immediately after the intervention, as measured by SF-36 (Beckie & Beckstead 2011, Pinto et al. 2013). However, Beckie and Beckstead (2011) focused their research on women and multiple changes in behaviour (e.g. diet, exercise and stress management) based on the TTM and Pinto et al. (2013) focused theirs on exercise maintenance in patients after phase II cardiac rehabilitation. The other two studies indicated that the TTM-based exercise intervention had no significant effect on QoL (Taylor et al. 2006, Hughes et al. 2007). In detail, Taylor et al. (2006) found that a lifestyle exercise programme based on the TTM and social cognitive theory resulted in no significant improvements in QoL as measured by SF-36 6 months after patients with prostate cancer underwent intervention. The authors explained that the lack of significant differences may be due to the limited power of the study, owing to a small sample size. Hughes et al. (2007) also revealed that an exercise consultation programme based on the TTM indicated no significant changes in all domains of SF36 after the 6-month intervention. The authors explained that this result was due to the high scores of all domains of SF-36 at baseline. Thus, it is imperative to conduct a study to examine the effect of a TTM-based, exercise stage– matched intervention on exercise behaviour and QoL in CHD patients.
TTM-based exercise intervention for CHD patients
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Theoretical framework of the study In this study, the design of the exercise stage–matched intervention (ESMI) was guided by the TTM (Prochaska & DiClemente 1983). The TTM consists of four constructs: stages of change, processes of change, self-efficacy for behavioural change and decisional balance. According to the stages of change, individuals are divided into one of five stages: pre-contemplation, contemplation, preparation, action and maintenance stages. The processes of change are covert and overt strategies and techniques that individuals engage in when they attempt to modify their behaviours (Prochaska et al. 1992). Self-efficacy for behavioural change is an important predictor of progress, with a linear increase from the pre-contemplation to the maintenance stage. Higher self-efficacy means that individuals have a higher level of confidence in their ability to engage in regular exercise. Decisional balance includes the benefits and
© 2014 John Wiley & Sons Ltd
The study Aim This study aimed to examine the effects of a TTM-based ESMI on exercise behaviour and QoL among sedentary patients with CHD. The primary outcome is exercise behaviour in terms of exercise stages of change and the duration of moderate-intensity exercise (minutes/week). The secondary outcome is QoL.
Hypotheses
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Patients in the experimental group would be more likely to be at the action and maintenance stages than those in the control and sham groups.
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design and group allocation. The CONSORT diagram of the study is shown in Figure 2.
ESMI
Decisional balance
Stages of change
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Increase exercise duration
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Self-efficacy
Improve quality of life
Figure 1 Theoretical framework of the study.
Patients in the experimental group would demonstrate longer duration of moderate-intensity exercise (minutes/week) than those in the control and sham groups. Patients in the experimental group would demonstrate greater improvement in QoL than those in the control and sham groups.
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• •
Design and methodology
This study was a randomized controlled trial with repeated measures design. In total, 196 patients were recruited and randomly allocated to the control group (n = 67), sham group (n = 64) or experimental group (n = 65) using a random number table (Yan 2005) with the stratification of the patients’ exercise stages of change (e.g. pre-contemplation, contemplation and preparation stages) at baseline. Data were collected at baseline (T0), immediately following intervention (T1), and at 3-month (T2) and 6-month (T3) follow-ups by a trained nurse who was blind to the study 4
Participants and setting This study was conducted in three tertiary hospitals in a large urban city of Southern China. These three hospitals provided similar conventional care. The inclusion criteria were: (i) having been diagnosed with angina pectoris or myocardial infarction (ICD9:410-413) or having undergone percutaneous coronary intervention (PCI), for at least 3 months as only patients with a stable condition or angina in the past 3 months were included (Wang & Hui 2004); (ii) sedentary [according to Centers for Disease Control and Prevention (1993), individuals with no or irregular exercise were viewed as having a sedentary lifestyle. These patients were at the pre-contemplation, contemplation and preparation stages of exercise behaviour according to the exercise stages of change scale (Courneya 1995)]; (iii) over 18 years old; and (iv) able to communicate and read in Mandarin. The exclusion criteria were: (i) had previously participated in any cardiac rehabilitation programme; (ii) having any cognitive impairment (e.g. dementia) or psychiatric illnesses (e.g. psychosis); (iii) having depression as ascertained by scores equal to or higher than 11 on the Hospital Depression Subscale (HADS-D) (Arving et al. 2008); and (iv) having contraindications for exercise training, such as unstable angina, critical aortic stenosis, uncontrolled symptomatic heart failure (e.g. New York Heart Association Classification III/IV) and uncontrolled atrial or ventricular arrhythmias (e.g. atrial fibrillation) (Briffa et al. 2006).
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Processes of change
Sample size determination The sample size of this study was calculated to achieve a medium effect size of 025 for ANOVA analysis (Cohen 1988), a power of 080, three groups (u = 2) and an attrition rate of 20% (Jiang 2005) with a significant level of 005 (two-tailed test). Thus, 189 patients were required with 63 patients in each group (Cohen 1988). Randomization A total of 196 eligible patients were enrolled in this study. The patients were first stratified by their exercise stages of change indicated by their baseline data and then were randomly allocated to the control, sham, or experimental group according to a random number table (Yan 2005). Interventions Control group. Patients in the control group received only conventional care, which consisted of simple and unstruc© 2014 John Wiley & Sons Ltd
JAN: ORIGINAL RESEARCH: EMPIRICAL RESEARCH – QUANTITATIVE
TTM-based exercise intervention for CHD patients
Screening for eligibility - Screening assessment - Sign consent form
T0: Baseline data collection (N = 196): Demographic and clinical data, exercise stages of change (ESC), moderate-intensity exercise duration (MED) and quality of life (QoL)
4 dropouts - Diagnosed with lung cancer (1) - Too busy with taking care of her husband who was diagnosed with gastric cancer (1) - Left Xiamen City (1) - Refusal (1)
‘Sham’ group (n = 64)
Experimental group (n = 65)
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Control group (n = 67)
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Randomisation with stratification of patients’ exercise stages of change
11 dropouts - Diagnosed with lung cancer (1) - Too busy with taking care of grandchild (2) - Left Xiamen City (2) - Refusal (6)
9 dropouts - Left Xiamen City (3) - Hospitalised (1) - Refusal (5)
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T1 : Immediate post-intervention (n = 172): ESC, MED and QoL 8 dropouts - Became sick (1) - Left Xiamen City (2) - Refusal (5)
1 dropout - Left Xiamen City (1)
1 dropout - Felt uncomfortable (1)
T2 : Three-month follow-up (n = 162): ESC, MED and QoL
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5 dropouts - Hospitalised (1) - Left Xiamen city (2) - Not contactable (1) - Refusal (1)
5 dropouts - Left Xiamen city (2) - Not contactable (1) - Refusal (2)
2 dropouts - Refusal (2)
T3 : Six-month follow-up (n = 150): ESC, MED and QoL
Figure 2 The CONSORT diagram of the study.
tured patient education about diet, exercise and medication suited to cardiac patients. Sham group. Patients in the sham group received conventional care, a 2-hour patient education session, a booklet about cardiac rehabilitation and eight weekly sessions of general patient education about exercise. The 2-hour patient education session included: (i) an introduction to the heart and CHD; (ii) the risk factors of CHD; (iii) the diagnostic investigation and treatment of CHD; and © 2014 John Wiley & Sons Ltd
(iv) information about diet and exercise. Patient education was delivered in groups of 6–10 patients. The booklet on cardiac rehabilitation (developed by the Hong Kong Cardiac Rehabilitation and Prevention Centre of Tung Wah Hospital and the organization Care for Your Heart) was given to the patients immediately after the 2-hour patient education session. The 8 weekly follow-up sessions of general patient education on exercise were delivered after the 2-hour patient education session via face-to-face or telephone contacts, but each patient was required to receive 5
L-X. Zhu et al.
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Experimental group. Patients in the experimental group received conventional care, the same 2-hour patient education session and the booklet about cardiac rehabilitation as the sham group, and 8 weekly sessions of ESMI, together with exercise stage–matched pamphlets. The detailed ESMI has been described elsewhere (Zhu et al. 2014). In formulating the ESMI, guidelines – such as goals, processes of change and strategies and techniques for changing exercise behaviour at each stage – were set with reference to those developed by Burbank and colleagues (Burbank et al. 2002). Briefly, the goal for patients at the pre-contemplation stage was to increase their awareness of the need to change. Information about the potential benefits of exercise and risks of sedentary lifestyle and possible ways of engaging in exercise at home were provided. The discussions focused on encouraging the patients to think about and initiate change. The goal for patients at the contemplation stage was to increase their motivation and confidence in their ability to change. Attention was focused on finding out what was stopping the individual from engaging in exercise and decreasing the barriers to exercise and further discussing the benefits of exercise. For patients at the preparation stage – that is, those who were prepared to engage in exercise – the goal was to negotiate a plan for exercising and to undergo a physical examination with a cardiologist, who would give an exercise prescription (e.g. mode, frequency, intensity, duration and progression of exercise) based on the patient’s physical condition. They selected their preferred exercise mode from a list of examples of moderate-intensity exercise (30–60 METs) (Ainsworth et al. 2000), such as brisk walking (3– 4 mph) and tai chi. The goal for those at the action stage was to reaffirm commitment and follow–up to prevent relapse. This was done through rewarding regular exercise and seeking social support to maintain it. The researcher (ZLX) delivered the ESMI according to the aforementioned guidelines throughout the whole study. The ESMI was carried out after the 2-hour patient education session. ZLX assessed each patient weekly according to the exercise stages of change scale (Courneya 1995) before delivering the ESMI. The ESMI was delivered through face-to-face or telephone contact according to the patients’ availability, but each patient was required to receive two sessions of face-to-face contact over the
8 weeks (the same as that of the sham group). Each face-to-face contact lasted about 30 minutes, while each telephone contact was around 10 minutes, depending on the complexity of the patient’s concerns. Patients in the experimental group also received exercise stage–matched pamphlets, so they could review the strategies and techniques implemented at each stage at home. These pamphlets were developed with reference to those designed by Blissmer (2000), taking into account the factors of CHD and the guidelines of the ESMI. To ensure the patients’ fidelity to the intervention, they used a logbook to record their exercise, including the type of exercise that they had engaged in and the frequency, intensity and duration of each episode. With the help of the logbook, the patients could be monitored on whether they had adhered to the intervention at home. During the 8-week intervention period, the patients’ adherence was monitored by cross-checking the weekly compliance records and the logbook information through either face-to-face or telephone contacts. The weekly contacts also monitored the patients’ safety for undertaking exercise.
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two sessions of face-to-face contact over the 8 weeks. Each face-to-face session lasted about 30 minutes, while each telephone contact lasted about 5 minutes. The 8-week patient education included compliance checking and delivering information related to the benefits and importance of regular exercise.
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Data collection
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Data were collected from September 2009–January 2011. Data were collected at four time points by the trained nurse. At baseline, before allocating the patients into groups, the nurse collected the patients’ demographic and clinical data from their self-report and medical records, as well as the baseline data (T0). After completion of the 8-week intervention, the nurse collected data again immediately after the intervention (T1) and at 3-month (T2) and 6-month (T3) follow-ups. Instruments In this study, exercise behaviour was measured by exercise stages of change and moderate-intensity exercise duration (minutes/week). Patients’ exercise stages of change were assessed by the exercise stages of change scale (Courneya 1995), which consists of one item (‘Do you engage in exercise regularly?’), with five statements representing each stage from the pre-contemplation to the maintenance stage: (i) ‘No and I do not intend to in the next 6 months’; (ii) ‘No, but I intend to in the next 6 months’; (iii) ‘No, but I intend to in the next 30 days’; (iv) ‘Yes, I have been for less than 6 months’; and (v) ‘Yes, I have been for more than 6 months’. Regular exercise refers to accumulating at least 30 minutes of moderate-intensity exercise throughout the day more than 5 days of the week (American College of Sports Medicine 2006). Patients were asked to select the © 2014 John Wiley & Sons Ltd
JAN: ORIGINAL RESEARCH: EMPIRICAL RESEARCH – QUANTITATIVE
Ethical considerations
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Before commencing the study, ethics approval was granted by the Human Subjects Ethics Committee of the university and access approvals were obtained from the three participating hospitals. The purposes and procedures of the study were explained to each patient by ZLX using an information sheet and a consent form was obtained if the patient agreed to participate in the study. Voluntary participation was emphasized. A code number was assigned to each patient and all collected data were kept anonymous. This study has been registered at the Chinese Clinical Trial Registry (Registered No.: ChiCTR-TRC-12002852).
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statement that best described their current level of exercise. This scale has been tested to have good reliability. The 2-week test–retest reliability was 079 (Courneya 1995). This scale was translated into Chinese by Tung (2003) using forward-translation, back-translation and panel review and showed good acceptance (Tung 2003). A logbook was provided to each patient to record the details of his/her daily exercise, including the type of exercise; frequency, intensity and duration of each episode of exercise; whether angina occurred during exercise; and the number of additional anti-anginal medicine tablets or pills taken due to exercise. The intensity of exercise was assessed by Borg’s Rating of Perceived Exertion (RPE) Scale, which ranges from six (very, very light)–20 (exhausted). Moderate-intensity exercise referred to exercise up to RPE 11–13 and 30–60 METs (Ainsworth et al. 2000) performed in the past week. The patients’ moderate-intensity exercise duration (minutes/week) was assessed based on their selfreport and their logbook at each time point. QoL was measured by SF-36, which is a generic and comprehensive instrument to measure health-related QoL in the previous 4 weeks (Ware & Sherbourne 1992, McHorney et al. 1993). It measures eight domains of health: physical functioning, role-physical, bodily pain, general health perception, vitality, social functioning, role-emotional and mental health. These eight domains can be grouped into two summary dimensions: the physical component summary (PCS) and the mental component summary (MCS). The PCS includes the first four domains of health and the MCS includes the last four. A Chinese version of SF-36, which was translated by Fang (2005), was used in this study to measure the QoL of the participants. The test–retest reliability coefficients of these eight subscales ranged from 06–09 (Jiang 2005). Each subscale was computed to give a scaled score ranging from 0 (lowest level of well-being)–100 (highest level of wellbeing).
TTM-based exercise intervention for CHD patients
Data analysis
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Data analyses were conducted based on the intention-to-treat principle of analysis. Last observation carried forward (LOCF) was employed to handle missing data. After conducting the normality and homogeneity tests, data on exercise duration and each domain of the SF-36 were not normally distributed and the homogeneity of variance was also violated among the three groups. Thus, the differences in demographic and clinical data and exercise stages of change among the three groups were compared by the chi-square test. The differences of exercise duration, each domain of SF36, PCS and MCS among the three groups were analysed by the Kruskal–Wallis test at each time point. The Friedman test was adopted for within-group comparisons of outcome variables over time. All statistical analyses were performed using SPSS 21.0 (IBM, Armonk, NY, USA). The significant level of data analysis was set at 005 with two-tailed tests.
Validity and reliability
Validated instruments with good psychometric properties were adopted to enhance the validity and reliability of the data. All data were carefully checked immediately after being collected to avoid any missing answers. Data were crosschecked for verification after being entered in SPSS. Descriptive analyses were used to identify any obvious data errors and outliers. All suspicious data, including outliers, were checked with reference to the original data sources and errors (if found) corrected by the researcher. Related statistical assumptions were tested before conducting data analyses. © 2014 John Wiley & Sons Ltd
Results
A total of 196 patients were recruited, of whom 46 patients withdrew from the study during the study period. The main reasons for withdrawal are shown in Figure 2. Their ages ranged from 26–82 years old, with an average age of 638 (SD 96). There were no significant differences in demographic and clinical characteristics and baseline outcome measures among the control, sham and experimental groups in this study (Tables 1 and 2).
Exercise behaviour All the three groups increased the number of patients at the action and maintenance stages (engaging in regular exercise) after the 8-week intervention. More patients in the experimental group than those in the control and sham 7
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Table 1 Demographic and clinical characteristics of the patients. Experimental group (n = 65) n (%)
Chi-square test v2
P
14 (209) 29 (433) 24 (358)
21 (328) 30 (469) 13 (203)
25 (385) 29 (446) 11 (169)
9060
0060
49 (731) 18 (269)
49 (766) 15 (234)
8 (119) 59 (881)
3 (47) 61 (953)
56 (836) 11 (164) 45 (672) 16 (239) 6 (90) 2 (45) 61 (896) 4 (60)
45 (692) 20 (308)
0880
0644
4 (62) 61 (938)
2746
0253
16 (250) 31 (484) 17 (266)
13 (200) 39 (600) 13 (200)
0293
0864
52 (813) 12 (188)
48 (738) 17 (261)
3314
0507
43 (671) 16 (250) 5 (78)
45 (693) 11 (170) 9 (138)
2476
0651
0 (00) 57 (890) 7 (109)
1 (15) 59 (908) 5 (77)
2938
0568
38 26 41 21 41
43 22 45 21 46
3249
0197
0688 0153 3650
0709 0926 0161
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12 (179) 38 (567) 17 (254)
34 33 42 20 53
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Sham group (n = 64) n (%)
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Age ≤60 years 61–70 years >70 years Gender Male Female Marital status Single/widowed Married Education Primary school Secondary school College or above Current employment status Not working Part-time/full-time work Family income per month ≤$5,000 RMB $5,001–10,000 RMB ≥$10,001 RMB Type of medical payment Fully reimbursed Partially reimbursed Totally self-paid Diagnosis Angina pectoris Myocardial infarction PCI/stent Diagnosed with diabetes mellitus Diagnosed with hypertension Smoking status Non-smoker Quit smoking Current smoker Alcohol drinking Non-drinker Quit drinking Current drinker Exercise stages of change (T0) Pre-contemplation Contemplation Preparation HADS-D scores [mean (SD)]
Control group (n = 67) n (%)
(507) (493) (627) (299) (791)
(594) (406) (641) (328) (641)
(662) (338) (692) (323) (708)
30 (469) 20 (313) 14 (219)
35 (538) 21 (323) 9 (138)
1762
0779
55 (821) 9 (134) 3 (45)
53 (828) 6 (94) 5 (78)
50 (769) 7 (108) 8 (123)
3157
0532
10 9 48 22
17 9 38 28
11 17 37 24
3233
0199
3420
0181*
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31 (463) 23 (343) 13 (194)
(149) (134) (716) (23)
(266) (141) (594) (24)
(169) (262) (569) (20)
*Kruskal–Wallis test. PCI, percutaneous coronary intervention; HADS-D, Depression Subscale of Hospital Anxiety and Depression Scale.
groups were found to be at the action and maintenance stages at time points T1–T3 (Figure 3) and these differences among the three groups at T1, T2 and T3 were significant when the chi-square test was adopted to analyse the differ8
ences (P < 0001). The decreasing trend in the number of patients at the action and maintenance stages was also observed in the experimental group from T1–T3 (Figure 3). © 2014 John Wiley & Sons Ltd
T2 mean (SD)
435 (1227) 1354 (2074) 2429 (2449)
833 (113) 852 (110) 875 (138)
720 (407) 691 (410) 800 (337)
765 (232) 762 (235) 876 (171)
573 (257) 646 (213) 735 (200)
684 (180) 717 (162) 798 (141)
836 (223) 834 (199) 919 (165)
344 (870) 1091 (1993) 2466 (2523)
806 (126) 827 (114) 864 (137)
© 2014 John Wiley & Sons Ltd 799 (359) 742 (383) 862 (265)
822 (222) 799 (224) 877 (167)
560 (237) 642 (208) 718 (210)
683 (192) 709 (169) 802 (151)
828 (224) 816 (227) 900 (176)
0002**
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Effects of a transtheoretical model–based exercise stage–matched intervention on exercise behaviour and quality of life in patients with coronary heart disease: a randomized controlled trial
Accepted for publication 24 May 2014
Correspondence to S-C. Ho: e-mail: [email protected]
Z H U L - X . , H O S - C . , S I T J . W . H . & H E H - G . ( 2 0 1 4 ) Effects of a transtheoretical model–based exercise stage–matched intervention on exercise behaviour and quality of life in patients with coronary heart disease: a randomized controlled trial. Journal of Advanced Nursing 00(0), 000–000. doi: 10.1111/jan.12469
Abstract
Aim. To examine the effects of a transtheoretical model–based exercise stage– matched intervention on exercise behaviour and quality of life in patients with coronary heart disease. Background. Exercise-based cardiac rehabilitation has been shown to be beneficial to quality of life for patients with coronary heart disease. However, patients’ participation in rehabilitation programmes is poor. The transtheoretical model has been found to be an effective model for changing exercise behaviour in various populations; however, few studies have examined its effects on patients with coronary heart disease. Design. Randomized controlled trial. Methods. A total of 196 eligible patients were recruited from September 2009– January 2011 and randomly allocated to the control, ‘sham’ or experimental group. Outcome measures including exercise behaviour and quality of life were assessed at baseline, immediate postintervention and at 3- and 6-month followups. The chi-square test and Kruskal–Wallis test were used to analyse data. Results. Findings showed that, compared with the other two groups, patients in the Experimental group were more likely to be at the action and maintenance stages according to the exercise stages of change scale. They also showed longer moderateintensity exercise duration as recorded by a logbook and significantly greater improvements in physical functioning, general health, vitality, social functioning, mental health, physical component summary and mental component summary of SF-36 after the 8-week intervention and up to 3- and 6-month follow-ups. Conclusion. The transtheoretical model–based exercise stage–matched intervention has positive effects on exercise behaviour and quality of life in patients with coronary heart disease.
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Li-Xia Zhu PhD RN PhD Graduate, Post-doctoral Researcher School of Nursing, The Hong Kong Polytechnic University, Hong Kong, China Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Li-Xia Zhu, Shuk-Ching Ho, Janet Wing Hung Sit & Hong-Gu He
Shuk-Ching Ho PhD RN Assistant Professor School of Nursing, The Hong Kong Polytechnic University, Hong Kong, China
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Janet Wing Hung Sit PhD RN Associate Professor The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong, China
Hong-Gu He MD PhD RN Assistant Professor Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Keywords: coronary heart disease, exercise behaviour, exercise stage–matched intervention, nursing, quality of life, transtheoretical model
© 2014 John Wiley & Sons Ltd
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L-X. Zhu et al.
Patients with coronary heart disease have poor quality of life and regular exercise or exercise-based cardiac rehabilitation has been shown to be beneficial for improving their quality of life. Patients’ participation in, and adherence to, exercise programmes is poor. The transtheoretical model has been found to be an effective model for changing exercise behaviour; however, few studies have examined the effects of such interventions on
patients scored lower in most domains of SF-36 within a period of 25 years following myocardial infarction (Worcester et al. 2007, Zhang et al. 2011). Exercise-based cardiac rehabilitation has been shown to benefit CHD patients’ QoL (Heran et al. 2011). However, participation in, and adherence to, exercise-based cardiac rehabilitation programmes is poor (Suaya et al. 2007, van Engen-Verheul et al. 2013). Thus, improving the uptake of, and adherence to, exercise-based cardiac rehabilitation programmes – which in turn improve CHD patients’ QoL – is a global concern.
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Why is this research or review needed?
patients with coronary heart disease.
Patients who received exercise stage–matched intervention
were more likely to engage in regular exercise (namely, at the action and maintenance stages) and demonstrated
longer duration of moderate-intensity exercise (minutes/ week) than those who received conventional care and general patient education after the 8-week intervention and up to their 6-month follow-up.
Patients who received exercise stage–matched intervention
showed greater improvements in quality of life than those
who received conventional care and general patient educa-
How should the findings be used to influence policy/ practice/research/education?
To provide evidence that the transtheoretical model–based, exercise stage–matched intervention has positive effects on
exercise behaviour and quality of life in patients with coronary heart disease.
It is necessary and important to provide patients with cor-
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onary heart disease with a structured, transtheoretical model–based patient education programme.
Introduction
Coronary heart disease (CHD) is the leading cause of death and disability among adults worldwide and has become the third leading cause of death among Chinese adults (Health Statistics Information Centre of the Ministry of Health PRC 2012). Previous studies have shown that patients with CHD have poor quality of life (QoL) (Bengtsson et al. 2004, Brink et al. 2005, Kristofferzon et al. 2005). Compared with an age- and sex-matched healthy population, CHD
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Exercise training alone or exercise-based cardiac rehabilitation has been shown to be beneficial for improving the QoL of patients with heart disease (Heran et al. 2011). However, patients’ participation in, and adherence to, exercise-based cardiac rehabilitation programmes has been discouraging globally. Previous studies have shown that only 26–835% of CHD patients participate in at least one session of a formal cardiac rehabilitation programme (Goto et al. 2007, Suaya et al. 2007, Bethell et al. 2008, Dressler & Lewin 2013, van Engen-Verheul et al. 2013), with the participation rate being lowest in patients with stable angina pectoris (van Engen-Verheul et al. 2013). Of those who participated in cardiac rehabilitation programmes, the dropout rates reached approximately 50% during the first 6 months of the programmes (Sanderson & Bittner 2005, Sarrafzadegan et al. 2007). Thus, it is imperative to call for a more patient-centred approach in tailoring interventions to improve the uptake of, and adherence to, exercise-based cardiac rehabilitation programmes, which in turn could improve CHD patients’ QoL. Previous studies have illustrated that the transtheoretical model (TTM) (Prochaska & DiClemente 1983) is effective for changing exercise behaviour in various populations from young adults (Kim 2008, Huang et al. 2009) to older people (M€ arki et al. 2006, Greaney et al. 2008). Unfortunately, few studies have examined the effects of TTMbased interventions on changes in exercise behaviour in cardiac patients (Zhu et al. 2013). Our literature review found that only four studies have used the TTM to motivate cardiac patients to engage in or maintain regular exercise. These four studies have shown inconsistent conclusions about adherence to regular exercise and all of them recruited participants immediately after completion of a formal cardiac rehabilitation programme (Hughes et al. 2002, 2007, Naser et al. 2008, Pinto et al. 2011). In addi-
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tion after the 8-week intervention and up to their 6-month follow-up.
Background
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What are the key findings?
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barriers of changing their behaviour, which vary across stages of change. The TTM offers a promising approach to integrating the stages and processes of change. Based on the stages of change, researchers can develop stage-matched interventions, which refer to interventions that match the individual’s current stage of behavioural change (Prochaska & DiClemente 1983). Thus, ESMI refers to the delivery of strategies and techniques (processes of change) that are matched to the individual’s current stage of readiness for change in his/her exercise behaviours (Kim 2008). For patients at different exercise stages of change, different goals are set and different processes of change (strategies and techniques) are used to help them move on to a more advanced stage. Subsequently, ESMI improves individuals’ exercise stages of change, exercise self-efficacy and exercise decisional balance (Kim 2008, Huang et al. 2009). Individuals with higher exercise self-efficacy have more confidence about changing their exercise behaviour, which results in a more positive shift in exercise stages of change. When the benefits of changing one’s exercise behaviour increase to the same level as the barriers, individuals start to take action to change their exercise behaviour. When the benefits outweigh the barriers, individuals are more likely to successfully adhere to regular exercise, moving on to the action and maintenance stages. The result is motivation [a force that initiates, guides and maintains a goal-oriented behaviour (Cherry 2011)] to engage in regular exercise and increase exercise duration, which is beneficial for improving CHD patients’ QoL (Heran et al. 2011). A theoretical framework for the ESMI used in this study is shown in Figure 1.
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tion, few studies have examined the effects of the TTMbased exercise interventions on QoL among CHD patients as a result of changes in exercise behaviour. Few studies have demonstrated inconsistent conclusions in their effect on QoL. Two studies showed that TTM-based exercise interventions resulted in significantly greater improvement in QoL immediately after the intervention, as measured by SF-36 (Beckie & Beckstead 2011, Pinto et al. 2013). However, Beckie and Beckstead (2011) focused their research on women and multiple changes in behaviour (e.g. diet, exercise and stress management) based on the TTM and Pinto et al. (2013) focused theirs on exercise maintenance in patients after phase II cardiac rehabilitation. The other two studies indicated that the TTM-based exercise intervention had no significant effect on QoL (Taylor et al. 2006, Hughes et al. 2007). In detail, Taylor et al. (2006) found that a lifestyle exercise programme based on the TTM and social cognitive theory resulted in no significant improvements in QoL as measured by SF-36 6 months after patients with prostate cancer underwent intervention. The authors explained that the lack of significant differences may be due to the limited power of the study, owing to a small sample size. Hughes et al. (2007) also revealed that an exercise consultation programme based on the TTM indicated no significant changes in all domains of SF36 after the 6-month intervention. The authors explained that this result was due to the high scores of all domains of SF-36 at baseline. Thus, it is imperative to conduct a study to examine the effect of a TTM-based, exercise stage– matched intervention on exercise behaviour and QoL in CHD patients.
TTM-based exercise intervention for CHD patients
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Theoretical framework of the study In this study, the design of the exercise stage–matched intervention (ESMI) was guided by the TTM (Prochaska & DiClemente 1983). The TTM consists of four constructs: stages of change, processes of change, self-efficacy for behavioural change and decisional balance. According to the stages of change, individuals are divided into one of five stages: pre-contemplation, contemplation, preparation, action and maintenance stages. The processes of change are covert and overt strategies and techniques that individuals engage in when they attempt to modify their behaviours (Prochaska et al. 1992). Self-efficacy for behavioural change is an important predictor of progress, with a linear increase from the pre-contemplation to the maintenance stage. Higher self-efficacy means that individuals have a higher level of confidence in their ability to engage in regular exercise. Decisional balance includes the benefits and
© 2014 John Wiley & Sons Ltd
The study Aim This study aimed to examine the effects of a TTM-based ESMI on exercise behaviour and QoL among sedentary patients with CHD. The primary outcome is exercise behaviour in terms of exercise stages of change and the duration of moderate-intensity exercise (minutes/week). The secondary outcome is QoL.
Hypotheses
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Patients in the experimental group would be more likely to be at the action and maintenance stages than those in the control and sham groups.
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design and group allocation. The CONSORT diagram of the study is shown in Figure 2.
ESMI
Decisional balance
Stages of change
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Increase exercise duration
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Self-efficacy
Improve quality of life
Figure 1 Theoretical framework of the study.
Patients in the experimental group would demonstrate longer duration of moderate-intensity exercise (minutes/week) than those in the control and sham groups. Patients in the experimental group would demonstrate greater improvement in QoL than those in the control and sham groups.
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• •
Design and methodology
This study was a randomized controlled trial with repeated measures design. In total, 196 patients were recruited and randomly allocated to the control group (n = 67), sham group (n = 64) or experimental group (n = 65) using a random number table (Yan 2005) with the stratification of the patients’ exercise stages of change (e.g. pre-contemplation, contemplation and preparation stages) at baseline. Data were collected at baseline (T0), immediately following intervention (T1), and at 3-month (T2) and 6-month (T3) follow-ups by a trained nurse who was blind to the study 4
Participants and setting This study was conducted in three tertiary hospitals in a large urban city of Southern China. These three hospitals provided similar conventional care. The inclusion criteria were: (i) having been diagnosed with angina pectoris or myocardial infarction (ICD9:410-413) or having undergone percutaneous coronary intervention (PCI), for at least 3 months as only patients with a stable condition or angina in the past 3 months were included (Wang & Hui 2004); (ii) sedentary [according to Centers for Disease Control and Prevention (1993), individuals with no or irregular exercise were viewed as having a sedentary lifestyle. These patients were at the pre-contemplation, contemplation and preparation stages of exercise behaviour according to the exercise stages of change scale (Courneya 1995)]; (iii) over 18 years old; and (iv) able to communicate and read in Mandarin. The exclusion criteria were: (i) had previously participated in any cardiac rehabilitation programme; (ii) having any cognitive impairment (e.g. dementia) or psychiatric illnesses (e.g. psychosis); (iii) having depression as ascertained by scores equal to or higher than 11 on the Hospital Depression Subscale (HADS-D) (Arving et al. 2008); and (iv) having contraindications for exercise training, such as unstable angina, critical aortic stenosis, uncontrolled symptomatic heart failure (e.g. New York Heart Association Classification III/IV) and uncontrolled atrial or ventricular arrhythmias (e.g. atrial fibrillation) (Briffa et al. 2006).
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Processes of change
Sample size determination The sample size of this study was calculated to achieve a medium effect size of 025 for ANOVA analysis (Cohen 1988), a power of 080, three groups (u = 2) and an attrition rate of 20% (Jiang 2005) with a significant level of 005 (two-tailed test). Thus, 189 patients were required with 63 patients in each group (Cohen 1988). Randomization A total of 196 eligible patients were enrolled in this study. The patients were first stratified by their exercise stages of change indicated by their baseline data and then were randomly allocated to the control, sham, or experimental group according to a random number table (Yan 2005). Interventions Control group. Patients in the control group received only conventional care, which consisted of simple and unstruc© 2014 John Wiley & Sons Ltd
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TTM-based exercise intervention for CHD patients
Screening for eligibility - Screening assessment - Sign consent form
T0: Baseline data collection (N = 196): Demographic and clinical data, exercise stages of change (ESC), moderate-intensity exercise duration (MED) and quality of life (QoL)
4 dropouts - Diagnosed with lung cancer (1) - Too busy with taking care of her husband who was diagnosed with gastric cancer (1) - Left Xiamen City (1) - Refusal (1)
‘Sham’ group (n = 64)
Experimental group (n = 65)
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Control group (n = 67)
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Randomisation with stratification of patients’ exercise stages of change
11 dropouts - Diagnosed with lung cancer (1) - Too busy with taking care of grandchild (2) - Left Xiamen City (2) - Refusal (6)
9 dropouts - Left Xiamen City (3) - Hospitalised (1) - Refusal (5)
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T1 : Immediate post-intervention (n = 172): ESC, MED and QoL 8 dropouts - Became sick (1) - Left Xiamen City (2) - Refusal (5)
1 dropout - Left Xiamen City (1)
1 dropout - Felt uncomfortable (1)
T2 : Three-month follow-up (n = 162): ESC, MED and QoL
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5 dropouts - Hospitalised (1) - Left Xiamen city (2) - Not contactable (1) - Refusal (1)
5 dropouts - Left Xiamen city (2) - Not contactable (1) - Refusal (2)
2 dropouts - Refusal (2)
T3 : Six-month follow-up (n = 150): ESC, MED and QoL
Figure 2 The CONSORT diagram of the study.
tured patient education about diet, exercise and medication suited to cardiac patients. Sham group. Patients in the sham group received conventional care, a 2-hour patient education session, a booklet about cardiac rehabilitation and eight weekly sessions of general patient education about exercise. The 2-hour patient education session included: (i) an introduction to the heart and CHD; (ii) the risk factors of CHD; (iii) the diagnostic investigation and treatment of CHD; and © 2014 John Wiley & Sons Ltd
(iv) information about diet and exercise. Patient education was delivered in groups of 6–10 patients. The booklet on cardiac rehabilitation (developed by the Hong Kong Cardiac Rehabilitation and Prevention Centre of Tung Wah Hospital and the organization Care for Your Heart) was given to the patients immediately after the 2-hour patient education session. The 8 weekly follow-up sessions of general patient education on exercise were delivered after the 2-hour patient education session via face-to-face or telephone contacts, but each patient was required to receive 5
L-X. Zhu et al.
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Experimental group. Patients in the experimental group received conventional care, the same 2-hour patient education session and the booklet about cardiac rehabilitation as the sham group, and 8 weekly sessions of ESMI, together with exercise stage–matched pamphlets. The detailed ESMI has been described elsewhere (Zhu et al. 2014). In formulating the ESMI, guidelines – such as goals, processes of change and strategies and techniques for changing exercise behaviour at each stage – were set with reference to those developed by Burbank and colleagues (Burbank et al. 2002). Briefly, the goal for patients at the pre-contemplation stage was to increase their awareness of the need to change. Information about the potential benefits of exercise and risks of sedentary lifestyle and possible ways of engaging in exercise at home were provided. The discussions focused on encouraging the patients to think about and initiate change. The goal for patients at the contemplation stage was to increase their motivation and confidence in their ability to change. Attention was focused on finding out what was stopping the individual from engaging in exercise and decreasing the barriers to exercise and further discussing the benefits of exercise. For patients at the preparation stage – that is, those who were prepared to engage in exercise – the goal was to negotiate a plan for exercising and to undergo a physical examination with a cardiologist, who would give an exercise prescription (e.g. mode, frequency, intensity, duration and progression of exercise) based on the patient’s physical condition. They selected their preferred exercise mode from a list of examples of moderate-intensity exercise (30–60 METs) (Ainsworth et al. 2000), such as brisk walking (3– 4 mph) and tai chi. The goal for those at the action stage was to reaffirm commitment and follow–up to prevent relapse. This was done through rewarding regular exercise and seeking social support to maintain it. The researcher (ZLX) delivered the ESMI according to the aforementioned guidelines throughout the whole study. The ESMI was carried out after the 2-hour patient education session. ZLX assessed each patient weekly according to the exercise stages of change scale (Courneya 1995) before delivering the ESMI. The ESMI was delivered through face-to-face or telephone contact according to the patients’ availability, but each patient was required to receive two sessions of face-to-face contact over the
8 weeks (the same as that of the sham group). Each face-to-face contact lasted about 30 minutes, while each telephone contact was around 10 minutes, depending on the complexity of the patient’s concerns. Patients in the experimental group also received exercise stage–matched pamphlets, so they could review the strategies and techniques implemented at each stage at home. These pamphlets were developed with reference to those designed by Blissmer (2000), taking into account the factors of CHD and the guidelines of the ESMI. To ensure the patients’ fidelity to the intervention, they used a logbook to record their exercise, including the type of exercise that they had engaged in and the frequency, intensity and duration of each episode. With the help of the logbook, the patients could be monitored on whether they had adhered to the intervention at home. During the 8-week intervention period, the patients’ adherence was monitored by cross-checking the weekly compliance records and the logbook information through either face-to-face or telephone contacts. The weekly contacts also monitored the patients’ safety for undertaking exercise.
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two sessions of face-to-face contact over the 8 weeks. Each face-to-face session lasted about 30 minutes, while each telephone contact lasted about 5 minutes. The 8-week patient education included compliance checking and delivering information related to the benefits and importance of regular exercise.
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Data collection
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Data were collected from September 2009–January 2011. Data were collected at four time points by the trained nurse. At baseline, before allocating the patients into groups, the nurse collected the patients’ demographic and clinical data from their self-report and medical records, as well as the baseline data (T0). After completion of the 8-week intervention, the nurse collected data again immediately after the intervention (T1) and at 3-month (T2) and 6-month (T3) follow-ups. Instruments In this study, exercise behaviour was measured by exercise stages of change and moderate-intensity exercise duration (minutes/week). Patients’ exercise stages of change were assessed by the exercise stages of change scale (Courneya 1995), which consists of one item (‘Do you engage in exercise regularly?’), with five statements representing each stage from the pre-contemplation to the maintenance stage: (i) ‘No and I do not intend to in the next 6 months’; (ii) ‘No, but I intend to in the next 6 months’; (iii) ‘No, but I intend to in the next 30 days’; (iv) ‘Yes, I have been for less than 6 months’; and (v) ‘Yes, I have been for more than 6 months’. Regular exercise refers to accumulating at least 30 minutes of moderate-intensity exercise throughout the day more than 5 days of the week (American College of Sports Medicine 2006). Patients were asked to select the © 2014 John Wiley & Sons Ltd
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Ethical considerations
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Before commencing the study, ethics approval was granted by the Human Subjects Ethics Committee of the university and access approvals were obtained from the three participating hospitals. The purposes and procedures of the study were explained to each patient by ZLX using an information sheet and a consent form was obtained if the patient agreed to participate in the study. Voluntary participation was emphasized. A code number was assigned to each patient and all collected data were kept anonymous. This study has been registered at the Chinese Clinical Trial Registry (Registered No.: ChiCTR-TRC-12002852).
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statement that best described their current level of exercise. This scale has been tested to have good reliability. The 2-week test–retest reliability was 079 (Courneya 1995). This scale was translated into Chinese by Tung (2003) using forward-translation, back-translation and panel review and showed good acceptance (Tung 2003). A logbook was provided to each patient to record the details of his/her daily exercise, including the type of exercise; frequency, intensity and duration of each episode of exercise; whether angina occurred during exercise; and the number of additional anti-anginal medicine tablets or pills taken due to exercise. The intensity of exercise was assessed by Borg’s Rating of Perceived Exertion (RPE) Scale, which ranges from six (very, very light)–20 (exhausted). Moderate-intensity exercise referred to exercise up to RPE 11–13 and 30–60 METs (Ainsworth et al. 2000) performed in the past week. The patients’ moderate-intensity exercise duration (minutes/week) was assessed based on their selfreport and their logbook at each time point. QoL was measured by SF-36, which is a generic and comprehensive instrument to measure health-related QoL in the previous 4 weeks (Ware & Sherbourne 1992, McHorney et al. 1993). It measures eight domains of health: physical functioning, role-physical, bodily pain, general health perception, vitality, social functioning, role-emotional and mental health. These eight domains can be grouped into two summary dimensions: the physical component summary (PCS) and the mental component summary (MCS). The PCS includes the first four domains of health and the MCS includes the last four. A Chinese version of SF-36, which was translated by Fang (2005), was used in this study to measure the QoL of the participants. The test–retest reliability coefficients of these eight subscales ranged from 06–09 (Jiang 2005). Each subscale was computed to give a scaled score ranging from 0 (lowest level of well-being)–100 (highest level of wellbeing).
TTM-based exercise intervention for CHD patients
Data analysis
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Data analyses were conducted based on the intention-to-treat principle of analysis. Last observation carried forward (LOCF) was employed to handle missing data. After conducting the normality and homogeneity tests, data on exercise duration and each domain of the SF-36 were not normally distributed and the homogeneity of variance was also violated among the three groups. Thus, the differences in demographic and clinical data and exercise stages of change among the three groups were compared by the chi-square test. The differences of exercise duration, each domain of SF36, PCS and MCS among the three groups were analysed by the Kruskal–Wallis test at each time point. The Friedman test was adopted for within-group comparisons of outcome variables over time. All statistical analyses were performed using SPSS 21.0 (IBM, Armonk, NY, USA). The significant level of data analysis was set at 005 with two-tailed tests.
Validity and reliability
Validated instruments with good psychometric properties were adopted to enhance the validity and reliability of the data. All data were carefully checked immediately after being collected to avoid any missing answers. Data were crosschecked for verification after being entered in SPSS. Descriptive analyses were used to identify any obvious data errors and outliers. All suspicious data, including outliers, were checked with reference to the original data sources and errors (if found) corrected by the researcher. Related statistical assumptions were tested before conducting data analyses. © 2014 John Wiley & Sons Ltd
Results
A total of 196 patients were recruited, of whom 46 patients withdrew from the study during the study period. The main reasons for withdrawal are shown in Figure 2. Their ages ranged from 26–82 years old, with an average age of 638 (SD 96). There were no significant differences in demographic and clinical characteristics and baseline outcome measures among the control, sham and experimental groups in this study (Tables 1 and 2).
Exercise behaviour All the three groups increased the number of patients at the action and maintenance stages (engaging in regular exercise) after the 8-week intervention. More patients in the experimental group than those in the control and sham 7
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Table 1 Demographic and clinical characteristics of the patients. Experimental group (n = 65) n (%)
Chi-square test v2
P
14 (209) 29 (433) 24 (358)
21 (328) 30 (469) 13 (203)
25 (385) 29 (446) 11 (169)
9060
0060
49 (731) 18 (269)
49 (766) 15 (234)
8 (119) 59 (881)
3 (47) 61 (953)
56 (836) 11 (164) 45 (672) 16 (239) 6 (90) 2 (45) 61 (896) 4 (60)
45 (692) 20 (308)
0880
0644
4 (62) 61 (938)
2746
0253
16 (250) 31 (484) 17 (266)
13 (200) 39 (600) 13 (200)
0293
0864
52 (813) 12 (188)
48 (738) 17 (261)
3314
0507
43 (671) 16 (250) 5 (78)
45 (693) 11 (170) 9 (138)
2476
0651
0 (00) 57 (890) 7 (109)
1 (15) 59 (908) 5 (77)
2938
0568
38 26 41 21 41
43 22 45 21 46
3249
0197
0688 0153 3650
0709 0926 0161
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12 (179) 38 (567) 17 (254)
34 33 42 20 53
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Sham group (n = 64) n (%)
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Age ≤60 years 61–70 years >70 years Gender Male Female Marital status Single/widowed Married Education Primary school Secondary school College or above Current employment status Not working Part-time/full-time work Family income per month ≤$5,000 RMB $5,001–10,000 RMB ≥$10,001 RMB Type of medical payment Fully reimbursed Partially reimbursed Totally self-paid Diagnosis Angina pectoris Myocardial infarction PCI/stent Diagnosed with diabetes mellitus Diagnosed with hypertension Smoking status Non-smoker Quit smoking Current smoker Alcohol drinking Non-drinker Quit drinking Current drinker Exercise stages of change (T0) Pre-contemplation Contemplation Preparation HADS-D scores [mean (SD)]
Control group (n = 67) n (%)
(507) (493) (627) (299) (791)
(594) (406) (641) (328) (641)
(662) (338) (692) (323) (708)
30 (469) 20 (313) 14 (219)
35 (538) 21 (323) 9 (138)
1762
0779
55 (821) 9 (134) 3 (45)
53 (828) 6 (94) 5 (78)
50 (769) 7 (108) 8 (123)
3157
0532
10 9 48 22
17 9 38 28
11 17 37 24
3233
0199
3420
0181*
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31 (463) 23 (343) 13 (194)
(149) (134) (716) (23)
(266) (141) (594) (24)
(169) (262) (569) (20)
*Kruskal–Wallis test. PCI, percutaneous coronary intervention; HADS-D, Depression Subscale of Hospital Anxiety and Depression Scale.
groups were found to be at the action and maintenance stages at time points T1–T3 (Figure 3) and these differences among the three groups at T1, T2 and T3 were significant when the chi-square test was adopted to analyse the differ8
ences (P < 0001). The decreasing trend in the number of patients at the action and maintenance stages was also observed in the experimental group from T1–T3 (Figure 3). © 2014 John Wiley & Sons Ltd
T2 mean (SD)
435 (1227) 1354 (2074) 2429 (2449)
833 (113) 852 (110) 875 (138)
720 (407) 691 (410) 800 (337)
765 (232) 762 (235) 876 (171)
573 (257) 646 (213) 735 (200)
684 (180) 717 (162) 798 (141)
836 (223) 834 (199) 919 (165)
344 (870) 1091 (1993) 2466 (2523)
806 (126) 827 (114) 864 (137)
© 2014 John Wiley & Sons Ltd 799 (359) 742 (383) 862 (265)
822 (222) 799 (224) 877 (167)
560 (237) 642 (208) 718 (210)
683 (192) 709 (169) 802 (151)
828 (224) 816 (227) 900 (176)
0002**
