Background

Coronary heart disease (CHD) is a chronic condition that often has serious physical, psychological and social consequences for the patients.1 Coronary heart disease causes disability, and it is estimated that disability-adjusted life years (DALYs) will rise from a loss of 85 million DALYs in 1990 to a loss of approximately 150 million DALYs in 2020. Coronary heart disease is the leading somatic cause of lost productivity; therefore, it is not only disabling for the patients but also a great burden to society.2

It is estimated that 42% and 38% of all deaths in European women and men, respectively, that occur below 75 years of age are due to CHD.2 The total number of patients living with CHD increases due to an aging population in the Western world and a reduced case fatality of acute coronary events. The earliest and most prominent decline in death caused by CHD was seen in the more affluent countries in Europe between the 1970s and 1990s and is partly attributed to better treatments for acute coronary events, heart failure and other cardiac conditions.2 This development illustrates the potential for prevention of premature deaths and for prolonging healthy life expectancy.2

In 2010, the human and economic arguments in favor of CHD prevention were estimated by the National Institute for Health and Clinical Excellence (NICE) as overwhelmingly positive regarding possible benefits and savings.2 For secondary prevention of CHD, multimodal, behavioral interventions are recommended. The interventions must include components such as nutrition advice, exercise training, weight management, smoking cessation and adherence to prescribed medication.2 The NICE states that the benefits from such interventions are numerous and include:2,3

* Narrowing of the gap in health inequalities

* Cost savings from the number of CHD events prevented

* Prevention of co-morbidity

* Cost savings associated with CHD such as medication, primary care visits and outpatient attendances

* Cost savings to the wider economy as a result of loss of production, benefit payments and pension costs of early retirement due to CHD

* Improvement of the quality of life (QoL) and length of CHD patients' lives.

Cardiac rehabilitation (CR) is a generic term for multimodal and behavioral interventions in the secondary prevention of CHD. The Scottish The Intercollegiate Guidelines Network (SIGN) develops evidence-based guidelines derived from systematic reviews of the scientific literature. The Scottish Intercollegiate Guidelines Network defines CR as: "[horizontal ellipsis]the process by which patients with cardiac disease in partnership with a multidisciplinary team of health professionals are encouraged and supported to achieve and maintain optimal physical and psychosocial health. The involvement of partners, other family members and carers is also important".4^(p.1)

The effect of CR has been studied in a Cochrane overview5 of reviews which included six systematic reviews. The results were based on 148 randomized-controlled trials (RCTs) and 98,093 patients. Exercise-based CR was found to be an effective and safe therapy to be used in the secondary prevention of clinically stable patients with CHD in relation to reducing readmissions and improving health related QoL.5

A systematic review, not included in the overview, also concluded that CR reduces patients' likelihood of depression and anxiety.6 In addition, a reduction in cholesterol and body mass index (BMI) was seen and patients tended to quit smoking and increase their exercise performance regarding intensity and duration.6 The effect of CR was similarly studied in a large community cohort of CHD-patients. The study showed that multidisciplinary CR was associated with a significant survival benefit in the first four years following an acute coronary syndrome (ACS) or cardiac intervention.7

Patients' lifestyles are based on long-standing behavioral patterns, which are influenced by a combination of environmental factors and personal and genetic factors.2,8 Psychosocial risk factors such as stress, social isolation and negative emotions may act as barriers to behavioral change, and therefore should be addressed in CR.2,8 Surveys show that a large proportion of CHD-patients still do not achieve the lifestyle, the risk factor levels and the therapeutic targets set in CR.2 In the standard CR setting, adherence to lifestyle recommendations and treatment regimens start to decline within six months of discharge from the hospital. Adherence to behavioral change concerning diet, exercise and smoking cessation after an ACS is associated with a significantly lower probability of re-infarctions compared with non-adherence.2

Secondary prevention of CHD is considered a lifelong effort.2,8 Cardiac rehabilitation efforts help to maintain long-term adherence to the optimal treatment program by educating the patients and repeatedly emphasizing the importance of achieving and maintaining the prescribed treatments and recommended lifestyle.2,8 Cardiac rehabilitation interventions may lead to better long-term results when it comes to behavioral change and somatic outcomes.2 Two RCTs have studied the effect of expanded CR versus standard CR.9,10 Expanded CR consisted of everything contained in the standard CR; in addition, expanded CR consisted of a longer period of CR, a better collaboration with general practice, more focus on support from relatives and more intensive CR-lessons, for example, one-to-one support and hands-on practices. Patients randomized to expanded CR had significantly fewer readmissions, re-infarctions and a lower probability of cardiovascular death compared to patients randomized to standard CR.9,10 A prospective cohort study studied the effect of expanded CR on socially vulnerable patients. The results showed that socially vulnerable patients who received expanded CR had a significantly better adherence to prescribed medication at the one year follow-up compared to socially vulnerable patients who received standard CR. The same trend was seen in lipid profile, systolic blood pressure and BMI.11

Based on this, it is important that a systematic review concerning expanded CR versus standard CR be conducted. Expanded CR is defined as any interventions in addition to standard CR or usual care. It is of importance to examine the role of CR in the 21st century given the fact that treatment options for CHD have improved rapidly during the last decades, and that subsequently there have been questions on whether CR has retained its efficacy.7 An initial search in the PubMed, the Cochrane Library, the JBI Database of Systematic Reviews and Implementation Reports, CINAHL and PROSPERO indicated that no systematic reviews or protocols on this topic exist.

Inclusion criteria

Types of participants

The current review will consider studies that include adult patients (over 18 years) diagnosed with CHD (also known as ischemic heart disease or coronary artery disease). The patients need to be have been included in a rehabilitation program after surviving an episode of ACS including unstable angina, non-STEMI or STEMI. Patients who have undergone percutaneous coronary intervention (PCI) or coronary bypass graft surgery will be included. Studies including patients with heart failure, diabetes, hypertension, hyperlipidaemia, hypercholesterolemia, depression and very old adults (over 65 years) will be excluded.

Types of interventions

The current review will consider studies that examine expanded CR compared to standard CR. Standard CR consists of different kinds of guideline-defined medical and behavioral interventions offered to patients diagnosed with CHD. Standard CR consist of components: lifestyle risk factor management, medical risk factor management, health behavior, diet and smoking cessation. Programs will be typically delivered by specialist nurses or physiotherapists.2

Expanded CR is defined as any different multimodal intervention/s in addition to standard CR or a variation of a standard CR intervention. Expanded CR will be typically reinforced, multi-factorial educational and behavioral interventions, and delivered or coordinated by a specialist.2

All kinds of CR settings where interventions are being undertaken will be considered for inclusion.

Outcomes

The current review will consider studies that include the following outcomes: all-cause mortality, cardiac mortality, all-cause hospital admission, readmissions due to any cardiac event and health status measured as adherence to secondary prevention guidelines. The adherence to secondary prevention guidelines will be measured using following outcomes and related measurements:

* Low density lipoprotein, high density lipoprotein and total cholesterol measured as mmol/ml

* Systolic blood pressure measured as mmHg

* Body mass index measured as weight (kg)/height (m)2

* Smoking status measured as yes/no

* Visits to general practice measured as number of visits

* Physical activity measured as min/week

* Dietary habits measured as grams of fruit and vegetables per day and daily intake of saturated fat.

The duration of studies and intensity of the CR will vary with no limitations for inclusion. After completion of the intervention all outcomes will be measured at follow-up with no restrictions regarding duration after CR in the included studies.

Types of studies

The current review will only consider peer-reviewed published and unpublished RCTs for inclusion.

Search strategy

The search strategy aims to find published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of PubMed, Scopus and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases and the trial registries: clincal.trials.gov and WHO trial registry, respectively. Third, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English, Danish, Swedish or Norwegian will be considered for inclusion in this review. Only studies published after the January 1, 2000 will be considered for inclusion. This is because secondary prevention underwent several changes during 1990-2000 including new recommendations in medical treatment (i.e. ACE inhibitors and statins) as well as invasive treatments (e.g. primary PCI and implantable cardioverter-defibrillators, and more uniform guidelines were published and endorsed).12,13

Since 2000, guidelines and recommendations regarding CR and secondary prevention have been regularly updated in international guidelines and still emphasize the same core components of CR.2,8 The databases and trial registries to be searched include PubMed, Scopus, CINAHL, clinical.trial.gov and the WHO trial registry.

Initial keywords to be used

For the concept population, the keyword "coronary heart disease" will be used. For intervention, the following keywords will be used: "cardiac rehabilitation", rehabilitation, "prevention programme", guidelines, recommendations, "patient education" and "patient management", expanded, multi-comprehensive, complex, multi-factorial, reinforced, respectively. For comparison, the keywords "standard care" and "usual care" will be used. For outcomes, the following keywords (MeSH) will be used: mortality, "patient readmission" "treatment outcome", "health status", "health behavior", lifestyle, "patient compliance" and "guideline adherence".

Assessment of methodological quality

Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using the standardized critical appraisal instrument from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer.

Data extraction

Quantitative data will be extracted by two independent reviewers from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Time to follow-up will be extracted as part of the evaluation.

Data synthesis

Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI System for the Unified Management of the Assessment and Review of Information (SUMARI). All results will be subject to double data entry. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data) of the outcomes (mortality, readmissions, cholesterol, BMI, hypertension, smoking status, physical activity and intake of saturated fat) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard chi-square and also explored using subgroup analyses based on the different study designs included in this review. Where statistical pooling is not possible, the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.

Acknowledgements

We thank the librarian from the Aarhus University Library, Hanne Caspersen, for assistance in the search of literature.

Appendix I: Appraisal instrument

MAStARI appraisal instrument

Appendix II: Data extraction instrument

MAStARI data extraction instrument

References