Abstract
Background Optimal physical activity levels have health benefits for patients with acute coronary syndrome (ACS) and are an important goal of cardiac rehabilitation (CR).
Purpose The purpose of this study was to systematically review literature regarding short-term effects (<6 months after completion of CR) and long-term effects (≥6 months after completion) of standard CR on physical activity levels in patients with ACS.
Data Sources PubMed, EMBASE, CINAHL, and PEDro were systematically searched for relevant randomized clinical trials (RCTs) published from 1990 until 2012.
Study Selection Randomized clinical trials investigating CR for patients with ACS reporting physical activity level were reviewed.
Data Extraction Two reviewers independently selected articles, extracted data, and assessed methodological quality. Results were summarized with a best evidence synthesis. Results were categorized as: (1) center-based/home-based CR versus no intervention, (2) comparison of different durations of CR, and (3) comparison of 2 types of CR.
Data Synthesis A total of 26 RCTs were included. Compared with no intervention, there was, at most, conflicting evidence for center-based CR and moderate evidence for home-based CR for short-term effectiveness. Limited evidence and no evidence were found for long-term maintenance for center-based and home-based CR, respectively. When directly compared with center-based CR, moderate evidence showed that home-based CR has better long-term effects. There was no clear evidence that increasing training volume, extending duration of CR, or adding an extra intervention to CR is more effective.
Limitations Because of the variety of CR interventions in the included RCTs and the variety of outcome measures in the included RCTs, pooling of data was not possible. Therefore, a best evidence synthesis was used.
Conclusions It would appear that center-based CR is not sufficient to improve and maintain physical activity habits. Home-based programs might be more successful, but the literature on these programs is limited. More research on finding successful interventions to improve activity habits is needed.
New drug therapies and revascularization techniques developed since the 1980s have dramatically changed the care of patients with cardiovascular conditions. Although cardiovascular disease is still the leading cause of death worldwide,1 since the introduction of these treatments, survival rates have increased, hospitalization has shortened, and cardiac function has been better preserved.2,3 Healthy lifestyle management is crucial for successful secondary prevention for this growing number of surviving patients.2,4 Cardiac rehabilitation (CR), including lifestyle education, has become increasingly important.
An important goal of CR is to improve daily physical activity levels. Regular physical activity reduces cardiac mortality by 20% to 30% in patients with myocardial infarction.5 Besides improving cardiac mortality, having an active lifestyle also has positive effects on the most important cardiovascular risk factors such as lipid profile, blood pressure, and body composition.6,7
The core of current standard CR consists of exercise programs led by physical therapists and complemented with educational or psychosocial interventions. Previous reviews reported that besides reducing cardiovascular risk factors and improving quality of life, standard CR does improve physical fitness.8,9 However, improved fitness (what a person can do) does not automatically result in a more active lifestyle (what a person really does in daily life).10
A review published in 1998 suggested that CR is not sufficient to change physical activity habits in the long term.11 However, medical practice has changed greatly since this review was written. The introduction of new drug therapies and revascularization techniques has shortened the time available in hospital for lifestyle education, putting more emphasis on CR.2,3 Moreover, a shift was seen from exercise-only CR to comprehensive programs including lifestyle education. It is unclear whether current standard CR programs are sufficient to improve and maintain physical activity levels. Therefore, the purpose of this study was to systematically review the recent scientific literature regarding the effect of current standard CR on levels of daily physical activity after acute coronary syndrome (ACS). To establish whether any improvements are maintained over time, we focused not only on the effects achieved immediately after CR but also on the effects in the long term.
Method
Data Sources and Searches
We systematically searched PubMed, EMBASE, CINAHL, and PEDro for relevant randomized clinical trials (RCTs). The search was limited to RCTs published between 1990 and December 2012. Randomized clinical trials published before 1990 were excluded because there have been major changes in medical practice since the development of new drugs and revascularization techniques in the 1980s. The search strings consisted of key words related to “heart disease,” “cardiac rehabilitation,” and “randomized clinical trials” and are presented in detail in the Appendix.
Study Selection
Randomized controlled trials fulfilling the following criteria were included:
The study population consisted of patients who had recently (<1 year) either survived ACS or undergone coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). Acute coronary syndrome usually occurs as a result of 1 of 3 problems: ST-elevation myocardial infarction, non–ST-elevation myocardial infarction, or unstable angina. In the Netherlands, these patients are usually treated with primary or elective PCI or CABG.
The intervention investigated was a CR program that lasted for at least 4 weeks. We defined CR as a structured exercise program combined with psychosocial and educational interventions undertaken in a center-based or home-based setting. As the exercise program forms the core of CR, interventions were categorized based on the location where the exercise program was performed. Thus, interventions containing a center-based exercise program were classified into the category center-based CR and interventions containing a home-based exercise program into the category home-based CR. Exercise-only interventions were excluded because this type of intervention is no longer considered as standard CR.2,6,12
An outcome measure for physical activity was reported. Physical activity was defined as any bodily movement produced by skeletal muscles and resulting in energy expenditure.13
Minimal follow-up was completion of the CR intervention.
The article was written in English, Dutch, French, or German.
Two reviewers (N.H., R.D.) independently selected relevant articles based on the inclusion criteria. Before reading the full text, a first selection was based on titles and abstracts. If an article was not available, we tried to obtain it by contacting the author. Disagreement between the 2 reviewers was discussed. If needed, a third reviewer (B.H.) resolved disagreements.
Data Extraction and Quality Assessment
Data on outcome measures for level of daily physical activity, study population, sample size, CR intervention, and control intervention were extracted by one reviewer (N.H.) using a standardized form and were checked by a second reviewer (R.D.). Data on outcome measures for physical activity were divided into short-term and long-term effects. Short-term effects were defined as effects measured less than 6 months after completion of CR; long-term effects were defined as effects measured 6 months or longer after completion of CR. In case multiple measurements within the short term or long term were reported in a single RCT, the measurement closest to completion of CR was used for analysis of short-term effectiveness, and the measurement closest to 1 year after completion of CR was used for analysis of long-term effectiveness. If data on the same RCT and population were reported in multiple publications, we extracted and presented them as originating from a single RCT. Disagreement was resolved by discussion or by the third reviewer (B.H.).
Two reviewers (N.H., R.D.) independently assessed the methodological quality of included RCTs using the list published by Furlan et al.14 This list consists of 12 items that are scored as “yes” (+), “no” (−), or “unsure” (+/−). A study was considered of high quality if at least 6 questions (≥50%) were scored as “yes.” Disagreement was resolved by discussion or by resorting to a third reviewer (B.H.).
Data Synthesis and Analysis
Due to the heterogeneity of CR interventions and the outcome measures for physical activity, pooling of data was not possible. Therefore, we used a best evidence synthesis.15 This method allows methodological quality and outcomes of the RCTs to be taken into account. Strength of evidence for the effectiveness of CR to improve physical activity in the short term (<6 months after completion of CR) and in the long term (≥6 months after completion of CR) was ranked as shown in Table 1.15
Strength of Evidencea
Results
Literature Search and Characteristics of the Selected RCTs
Our initial search resulted in 2,919 eligible articles. We finally included 26 RCTs (Figure). Of these, 9 RCTs compared CR with no intervention, 10 RCTs compared CR programs of different durations, and 7 RCTs compared 2 different types of CR (Tab. 2). When measuring physical activity, 21 RCTs used a self-report instrument (eg, questionnaire or activity diary), 3 RCTs used a pedometer, and 2 RCTs used both a self-report instrument and an accelerometer (Tab. 2).
Selection of articles. RCT=randomized clinical trial, CR=cardiac rehabilitation.
Treatment Specifications for Intervention Group and Control Intervention in the 26 RCTsa
Data Extraction
Details of the characteristics and results of the included RCTs are presented in the eAppendix.
Methodological Quality of the 26 RCTs
The results of the methodological quality assessment are presented in the eTable. Fourteen of the 26 RCTs scored 50% or more of the maximum score and were considered high quality. The most prevalent methodological flaws were: patients not blinded (100% of included RCTs), care provider not blinded (100% of RCTs), failure to report whether cointerventions were avoided (100% of RCTs), and failure to report whether treatment allocation was concealed (81% of RCTs).
Effectiveness of CR on Improving Physical Activity Levels
We performed a best evidence synthesis to summarize short-term effects (<6 months after completion of CR) and long-term effects (≥6 months after completion of CR). We categorized RCTs into studies investigating center-based and home-based CR versus no intervention, comparison of CR programs of different durations, and comparison of 2 types of CR. Duration of CR programs also varied greatly (4 weeks–4 years) within the above categories. To further improve meaningful interpretation of results, we analyzed and presented effects in every category in the following order: CR programs of short duration (1–3 months), CR programs of medium duration (4–11 months), and CR programs of long duration (≥12 months). Table 2 shows the treatment specifications, and Tables 3, 4, and 5 show the results of the best evidence synthesis per category.
Evidence for Effectiveness of CR Interventions Versus No Interventiona
Evidence for Effectiveness of 2 Different Durations of CR Compared With Each Othera
Evidence for Effectiveness of 2 Different Types of CR Compared With Each Othera
Effectiveness of CR Versus No Intervention
Seven RCTs investigated the effectiveness of center-based CR, and 2 RCTs investigated the effects of home-based CR versus a control group. Controls visited the hospital only for routine check-ups or received oral or written information about cardiac disease (Tab. 2).
Center-based CR versus no intervention.
For CR of short duration (1–3 months), Bertie et al16 (low quality, N=110) reported short-term effects of a 4-week CR program and showed that 3 months after completion of CR, the intervention group walked, on average, significantly more miles each day (8.2 miles) than the controls (6.6 miles) (P<.05). West et al17 (high quality, N=1,813) focused on long-term effectiveness and reported that 10 months after completion of CR, the percentage of active patients (>100 kcal/d) was higher in controls (12%) than in patients randomized to receive 6 to 8 weeks of CR (9%) (P=.05). According to the best evidence synthesis, there is limited evidence that, in the short term (<6 months after completion of CR), center-based CR of short duration is effective in improving physical activity levels. In the long term (≥6 months after completion), there is moderate evidence in favor of controls (Tab. 3).
For CR of medium duration (4–11 months), Engblom et al18 (high quality, N=171) reported no short-term effects 4 months after completion of an 8-month CR program. Lidell and Fridlund19 (low quality, N=116) performed 2 long-term measurements: at 6 months and at 4.5 years. Significant effects were found at the 6-month follow-up (66.7% of intervention group was active versus 27.6% of controls, P<.001); these improvements were not maintained after 4.5 years. As defined in our methods, the measurement closest to 1 year after completion of CR was used in the best evidence synthesis (ie, the results at 6-month follow-up). The best evidence synthesis revealed that there is no evidence that center-based CR of medium duration is effective in the short term (<6 months after completion of CR) and limited evidence that it is effective in the long term (≥6 months after completion of CR) (Tab. 3).
For CR of long duration (≥12 months), Otterstad20 (high quality, N=197) found that upon completion of a 2-year CR program, 67% of patients exercised for more than 1 hour every week compared with 46% of controls (P<.01). Naser et al21 (low quality, N=100) reported that upon completion of a 2-year CR program, 88% of patients were vigorously active at least 3 times per week for 20 minutes, whereas this figure was only 20% in controls (P<.05). Oldenburg et al22 (low quality, N=86) investigated a 1-year CR program and found no effects upon completion. We conclude that there is conflicting evidence for the short-term effectiveness (<6 months after completion of CR) of center-based CR of long duration. No RCTs focused on long-term effects (Tab. 3).
Home-based CR versus no intervention.
No RCTs were found for CR of short duration (1–3 months) or medium duration (4–11 months).
For CR of long duration (≥12 months), Ornish et al23 (high quality, N=48) reported that patients in the intervention group (1-year CR) increased from 0.26 exercise sessions per day at the start to 0.69 sessions per day on completion of the program; this increase was lower for controls (from 0.35 to 0.39 sessions per day) (P=.0008). There were no significant differences at 4-year follow-up.24 Higgins et al25 (low quality, N=105) reported that patients participating in a 1-year CR program increased from 35% being active before CR to 72% upon completion. This increase was larger than that in controls (53%–61%) (P<.001). In conclusion, there is moderate evidence that in the short term (<6 months after completion of CR), home-based CR of long duration is effective. There is no evidence for long-term effectiveness (Tab. 3).
Comparison of CR Programs of Different Durations
Ten of the 26 RCTs included in the review compared 2 center-based CR programs of different duration. In this category, short-term effects were defined as results measured <6 months after completion of the CR program with the longer duration, and long-term effects were defined as results measured 6 months or more after completion of the program with the longer duration.
CR of medium duration (4–11 months) versus short duration (1–3 months).
Janssen et al26 (high quality, N=210) reported that upon completion of 8-month CR, patients had increased their daily step count by 1,142 compared with the start of CR, whereas patients randomized to receive 3-month CR had decreased their daily step count by 522 by that time (P=.001). The RCT of Pinto et al27 (high quality, N=130) showed an increased duration of moderate exercise per week 3 months after completion of a CR program of 9 months for patients randomized to this longer program compared with patients randomized to receive 3-month CR (difference=0.47, standardized values, P=.008). Contrasting results were found by Moore et al28 (high quality, N=250), who did not find short-term differences between 3- and 5-month CR programs. Moore et al also reported long-term effects, but again no differences were found. We conclude that there is conflicting evidence that, in the short term (<6 months after completion of the CR program of medium duration), CR of medium duration is more effective than CR of short duration for improving levels of physical activity. In the long term, there is no evidence of effectiveness (Tab. 4).
CR of long duration (≥12 months) versus short duration (1–3 months).
Arrigo et al29 (low quality, N=261) reported that 73% of patients randomized to a 1-year CR program were physically active at least 3 times a week for 30 minutes upon completion of the program compared with 40% of patients randomized to receive 1 to 3 months of CR (P<.0005). Hughes et al30 (low quality, N=70) found that, upon completion of a 1-year CR program, patients exercised on average 130 minutes per week more than patients who had participated in a 3-month CR program (significant, P value not reported). In contrast, 3 other RCTs (1 high quality,31 2 low quality32,33) showed no short-term differences between CR of short duration and CR of long duration. Only 1 RCT also focused on long-term effects. Reid et al31 (high quality, N=392) did not find differences when comparing a 1-year program with a 3-month program. In conclusion, there is conflicting evidence that, in the short term (<6 months after completion of the CR program of long duration), CR of long duration is more effective than CR of short duration. In the long term, there is no evidence of effectiveness (Tab. 4).
CR of long duration (≥12 months) versus medium duration (4–11 months).
Giannuzzi et al34 (high quality, N=3,241) found that, upon completion of a 3-year CR program, patients had a higher physical activity score (23.8% on a self-report questionnaire) compared with patients randomized to a 6-month program (18.8%) (P=.001). Lear et al35 (high quality, n=302) did not find significant differences in the short term when comparing a 4-year program with a 4-month program. None of the RCTs looked at long-term differences. We conclude that there is conflicting evidence in the short term (<6 months after completion of the CR program of long duration) that CR of long duration is more effective than CR of medium duration. There were no RCTs investigating long-term differences (Tab. 4).
Comparison of 2 Types of CR
Center-based CR versus home-based CR.
For CR of short duration (1–3 months), Jolly et al36 (high quality, n=525) compared a 3-month center-based program with a 3-month home-based program and found no differences between the groups in the long term (7 months after completion). We conclude that there is no evidence for long-term differences (≥6 months after completion of CR) between center-based and home-based CR of short duration in effects on physical activity level. No RCTs investigated short-term differences (Tab. 5).
For CR of medium duration (4–11 months), Smith and colleagues37,38 (high quality, N=242) performed 2 long-term measurements: at 1- and 6-year follow-ups. One year after completion of the 6-month intervention, patients randomized to the home-based CR program had higher physical activity scores (Physical Activity Scale for the Elderly score=232.6) than patients randomized to the center-based CR program (Physical Activity Scale for the Elderly score=170.0) (P≤.0001).37 These differences were still significant at 6-year follow-up (166.7 for home-based CR versus 139.7 for center-based CR, P≤.001).38 As defined in our methods, the measurement closest to 1 year after completion of CR (ie, the 1-year follow-up) was used for the best evidence synthesis. We conclude that there is moderate evidence that home-based CR of medium duration is more effective in the long term (≥6 months after completion of CR) than center-based CR. There were no RCTs investigating short-term differences (Tab. 5).
For CR of long duration (≥12 months), Oerkild et al39 (high quality, N=75) found no differences between a center-based CR and a home-based CR program of 1 year's duration upon completion of the programs. In conclusion, there is no evidence for a difference in effectiveness in the short term (<6 months after completion of CR). There were no RCTs investigating long-term differences (Tab. 5).
Low-volume center-based CR versus high-volume center-based CR.
For CR of short duration (1–3 months), Hansen et al40 (high quality, N=119) compared center-based CR that involved a low-volume training program (3 × 40 min/wk endurance exercise for 3 months) with center-based CR that involved a high-volume training program (3 × 60 min/wk endurance exercise for 3 months). No differences were found in the long term (15 months after completion). We conclude that there is no evidence in favor of either a low-volume or a high-volume training program of short duration in the long term (≥6 months after completion of CR). There were no RCTs looking at short-term differences (Tab. 5).
No RCTs were found for CR programs of medium duration (4–11 months) or long duration (≥12 months).
CR including a self-efficacy intervention to increase physical activity versus standard CR.
No RCTs were found for CR of short duration (1–3 months) or long duration (≥12 months).
For CR of medium duration (4–11 months), Carlson et al41 (low quality, N=80) reported no significant differences upon completion between a 6-month CR program based on Bandura's self-efficacy theory and designed to enhance confidence for independent exercise and a 6-month standard center-based CR program. The best evidence synthesis reveals that, in the short term (<6 months after completion of CR), there is no evidence for the effectiveness of a self-efficacy CR intervention. There were no RCTs investigating long-term effects (Tab. 5).
CR including self-monitoring to increase physical activity versus standard CR.
No RCTs were found for CR of short duration (1–3 months) or long duration (≥12 months).
For CR of medium duration (4–11 months), Izawa et al42 (low quality, N=45) compared a 6-month self-monitoring and goal-setting intervention aimed at increasing physical activity with a 6-month, standard, center-based CR program. Six months after completion, the step count in patients randomized to the intervention group was significantly higher (10,458.7 steps per week) than in patients randomized to receive standard CR (6,922.5 steps per week) (P value not reported). In conclusion, in the long term (≥6 months after completion), there is limited evidence that the self-monitoring and goal-setting intervention is more effective than standard CR. There were no RCTs investigating short-term effects (Tab. 5).
CR including problem-based learning to increase physical activity versus standard CR.
No RCTs were found for CR of short duration (1–3 months) or medium duration (4–11 months).
For CR of long duration (≥12 months), Tingström et al43 (N=207) reported no significant differences upon completion of center-based CR including a problem-based learning intervention and aimed at increasing physical activity (duration=1 year) and standard center-based CR (also 1 year). The best evidence synthesis reveals that in the short term (<6 months after completion of CR), there is no evidence for a problem-based learning intervention. There were no RCTs investigating long-term effects (Tab. 5).
Discussion
This systematic review provides an overview of the evidence for the effectiveness of current standard CR compared with no intervention in improving physical activity levels in patients with ACS in the short term (<6 months after completion of CR) and in the long term (≥6 months). Besides, we focused on the optimal duration and type of CR to achieve and maintain changes in physical activity level.
Center-Based and Home-Based CR Compared With No Intervention
When center-based CR programs of different durations were compared with no intervention, both in the short term (<6 months after completion of CR) and in the long term (≥6 months after completion), at most limited evidence was found for the effectiveness of CR. In contrast to our expectations, there is even moderate evidence (based on one high-quality study) that controls are more active in the long term than patients randomized to center-based CR of short duration. However, reported differences were small (12% active versus 9% active, P<.005) and, according to the authors of one article,17 could be due to coincidence. We conclude that it seems doubtful whether physical activity improvements are reached during center-based CR programs.
Only 2 RCTs focused on effectiveness of home-based CR compared with no intervention. Outcomes were more promising. In the short term, there was moderate evidence of effectiveness for programs of long duration (≥12 months). However, no evidence was found for long-term maintenance (≥6 months after completion) of these results. When directly comparing home-based CR with center-based CR, moderate evidence also was found that home-based programs of medium duration (4–11 months) are more effective in the long term. However, no differences were found for programs of short duration (1–3 months) or long duration (≥12 months). A possible explanation for the somewhat better results found after home-based CR may be that physical activity is better incorporated into daily routine. Two recent observational studies showed that although physical activity increased during center-based CR, patients nevertheless failed to reach recommended levels by the end of the intervention. This result was primarily caused by patient nonactivity on the days they did not attend CR.44–46 These results may indicate that patients do not easily incorporate physical activity into daily life. Because there is limited research investigating the effectiveness of home-based CR, more research on this topic is needed before firm conclusions can be drawn.
Optimal Duration of CR
The duration of CR programs investigated in this review ranged from 4 weeks to 4 years. It is possible that given more time and guidance, patients can further increase or better maintain their physical activity level. However, conflicting evidence was found that patients completing a CR program of longer duration are more active shortly after the end of this program than patients who have followed a shorter program are at that time. For long-term maintenance of this higher activity level, no evidence was found. The optimal length of CR has not been studied extensively yet and might depend on the outcome of interest.31,47 According to a previous study,47 mental health recovery is mainly achieved beyond 3 months of CR. However, physical activity and physical function improvements peak in the first 3 months of CR, and there is no further improvement after this period.47 This finding is in line with the results of our review. We also found no clear evidence that greater improvements in physical activity are achieved when extending the length of CR to a duration beyond 3 months.
Type of CR
Besides variation in location (home or center) and duration of CR, there is variability in type of CR. No evidence was found that a higher training volume is more beneficial. There also was no evidence for the short-term effectiveness of performing a certain extra intervention during the standard CR period aimed at increasing physical activity levels. In the long term, there was limited evidence for the effectiveness of such an extra intervention, based on one low-quality study that studied the benefits of a behavioral self-monitoring approach as add-on therapy. Promising results were found in this study.42
It is essential that more research will focus on effective interventions to stimulate optimal activity levels because it seems doubtful whether standard CR is sufficient to improve and maintain an active lifestyle. Having an active lifestyle is essential in managing cardiac risk factors. Previous research showed that patients fail to reach recommended activity levels mainly on the days they did not attend CR.44–46 These results may indicate that patients do not easily incorporate physical activity into daily life. Therefore, we suggest that guidance on how to incorporate activity into daily life using behavioral techniques may increase physical activity on days patients do not attend CR and after completion of CR. Because the core of CR consists of exercise sessions led by physical therapists, they could play an important role in this guidance. Future research should focus on this role. Recently, 2 reviews examined what behavioral interventions aimed at increasing and maintaining physical activity are most effective for patients with cardiac conditions (both participating and not participating in CR). Behavioral interventions identified as promising were self-monitoring, goal setting, identifying barriers, and developing plans for relapse.48,49
Limitations
First, there are large differences between the included RCTs regarding the location, duration, and type of the CR intervention and follow-up term. To minimize heterogeneity, we defined strict inclusion criteria based on international guidelines2,6,12 to select only RCTs investigating CR programs that are currently considered to be standard. We also categorized RCTs based on location, type, and duration to improve meaningful interpretation of our results. Despite this organization, categories in this review are still relatively broad. Besides, the number of studies per category is low.
Second, 2 RCTs19,37,38 included in this review performed 2 measurements in the long term (≥6 months after completion) (ie, 6 months and 4.5 years19 and 1 and 6 years37,38). As defined in our methods, the measurement closest to 1 year after completion of CR was used in analysis. One year was arbitrarily chosen. If we would have chosen a follow-up time closer to the 4- or 6-year follow-up, it would only have changed our conclusion for long-term effectiveness of center-based programs of medium duration as reported by Lidell and Fridlund19 from limited to no evidence; the conclusions based on the results of Smith and colleagues37,38 remain the same.
Third, there was considerable variety in the measurement tools used to assess physical activity. In 21 of the 26 included RCTs, physical activity was self-reported using a wide variety of questionnaires or diaries. Therefore, we refrained from statistical pooling of the results. We used a best evidence synthesis, which is a next best solution and is a transparent method commonly applied when statistical pooling is not feasible or clinically viable.15 In addition, it is known that self-report measures often fail to demonstrate adequate validity or reliability, making it difficult to draw firm conclusions about the magnitude and clinical meaning of improvements.50–53
Fourth, only 54% of the RCTs were considered to be of high quality according to the criteria in Furlan and colleagues' list.14 There is evidence that a threshold of less than 50% of the criteria on Furlan and colleagues' list is associated with bias.54 The quality of the RCTs was often considered as low because information was missing on avoidance of cointerventions and on concealment of treatment allocation. Besides, patients and care providers were not blinded in all RCTs. However, correct blinding is difficult due to the nature of the studies.
Conclusions
Despite the fact that improving physical activity habits is an important goal of CR, it would appear that current standard center-based CR is not sufficient to improve and maintain physical activity habits. In this review, it was shown that home-based programs might be more successful to improve physical activity habits. However, more research on this topic is needed before firm conclusions can be drawn. There is wide variability in duration and type of CR programs offered. There is no clear evidence that increasing training volume, extending the duration of CR, or adding an extra intervention to CR leads to greater improvements in physical activity levels. Because having an active lifestyle is essential in managing cardiac risk factors and reducing mortality, future research should focus on finding successful interventions to achieve and maintain an active lifestyle.
Appendix.
Search Stringsa
a RCT=randomized clinical trial.
Footnotes
Ms ter Hoeve, Dr Huisstede, Dr van Domburg, Dr Sunamura, and Dr van den Berg-Emons provided concept/idea/research design. Ms ter Hoeve, Dr Huisstede, Dr van Domburg, and Dr van den Berg-Emons provided writing. Ms ter Hoeve provided data collection. Ms ter Hoeve, Dr Huisstede, and Dr van Domburg provided data analysis. Ms ter Hoeve, Dr Stam, and Dr van den Berg-Emons provided project management. Dr Stam and Dr van den Berg-Emons provided facilities/equipment. Dr Huisstede, Dr Stam, Dr Sunamura, and Dr van den Berg-Emons provided consultation (including review of the manuscript before submission). The authors thank Hedwig Kooijmans for her contribution to the quality assessment.
The study was presented as a poster presentation at the European Society of Cardiology Congress; August 31–September 4, 2013; Amsterdam, the Netherlands. The study was presented orally at the Annual Congress of the Netherlands Society of Physical and Rehabilitation Medicine; October 31–November 1, 2013; Noordwijkerhout, the Netherlands, and at the International Conference of Behavioral Medicine; August 20–23, 2014; Groningen, the Netherlands.
- Received October 23, 2013.
- Accepted September 24, 2014.
- © 2015 American Physical Therapy Association
References
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