STRENGTHS AND LIMITATIONS OF THIS STUDY

The strengths of this review include a rigorous methodology, following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols and having two independent reviewers conduct study selection, data extraction and quality assessment.

This review will evaluate existing sedentary behaviour interventions, and if possible, subgroup analyses will be conducted to explore the role of demographic characteristics, intervention duration, types, content and measurement tools in improving sedentary behaviour.

This review will be limited to studies published in English and Chinese language, hence the limited representativeness of findings.

Introduction

Sedentary behaviour is any waking behaviour characterised by energy expenditure of ≤1.5 metabolic equivalents while sitting, reclining or lying posture.1 In recent years, a growing number of studies have identified sedentary behaviour as a risk factor for increased cardiovascular disease morbidity and mortality.2 Coronary heart disease (CHD) is the most common cardiovascular disease with epidemiological features such as high disability, readmission and mortality3 and has continued to be a serious public health problem. The Lancet Physical Activity Series Working Group summarised the findings of several large-sample studies worldwide that sedentary behaviour contributes to 6% of the disease burden of CHD.4 In addition, a sedentary lifestyle is highly prevalent among patients with CHD, and the duration of sedentary time is considerably higher than that of the healthy population (10.4 hours vs 9.4 hours/day).5 Prolonged and sustained sedentary behaviour leads to reduced postural skeletal muscle contraction stimulus activity, decreased metabolic demands of the body, altered glucose metabolism, inflammatory pathways and oxidative stress pathways, which in turn damages the cardiovascular, endocrine and skeletal-muscular systems and is detrimental to the treatment and prognosis of the disease.6 7 Therefore, interventions to reduce sedentary behaviour are one of the keys to secondary prevention and self-management in patients with CHD.

In 2020, the WHO published a guideline on physical activity and sedentary behaviour that recommends increasing physical activity and limiting sedentary time for people with chronic conditions.8 Countless studies on physical activity targeting different diseases at different age groups have provided strong evidence to support the guidelines’ recommended frequency, duration and intensity by the guidelines. In contrast, strongly supported, evidenced-based, quantifiable sedentary guidelines are unavailable. In reality, although patients can meet physical activity requirements, they may still engage in highly sedentary behaviour. Furthermore, it is easier for patients with CHD to reduce sedentary behaviour than to meet physical activity requirements.9 10 Countries such as Canada and Australia have released guidelines and policies aimed at improving sedentary behaviour in adults and children.11 12 For healthy adults older than 18 years of age, it is recommended that total daily sedentary time be limited to 8 hours and screen time to 3 hours. This may provide some reference for managing sedentary behaviour in patients with CHD.

Prince’s review13 showed that interventions in adults with a focus on physical activity or that included a physical and sedentary behaviour component produced less consistent findings and generally resulted in modest reductions in sedentary time, but significant decreases in sedentary time can be achieved when interventions focus on reducing sedentary behaviour. Another review included 51 studies covering a variety of potential interventions to reduce sedentary time in adults, categorised as sedentary behaviour only, physical activity only, physical activity and sedentary behaviour, or lifestyle interventions (physical activity/sedentary behaviour and diet).14 In contrast to the Prince’s review, this review found no evidence of an effect of physical activity and combined physical activity/sedentary behaviour interventions on reducing sedentary time. A systematic review reported interventions for reducing sedentary behaviour in people with stroke.15 A total of 10 studies were included, of which 5 used physical activity interventions, 4 used multicomponent lifestyle interventions and only 1 used an intervention to reduce and interrupt sedentary behaviour. The final results showed that the above interventions did not increase or decrease the amount of sedentary time. Therefore, it is essential to identify more practical, sustainable and scalable interventions to manage sedentary behaviour effectively. Nowadays, increasing studies are shifting from offline face-to-face interventions to online tele-guidance, which uses electronic mobile technology to break through time and space constraints to provide timely and convenient health services.16 17

In summary, behaviour change is a complex, dynamic and cyclical process. The current dilemma lies in the lack of standardised guidelines for sedentary behaviour interventions for patients with CHD. This has led to inconsistent results due to differences in intervention implementation, operational procedures and assessment methods. We need to systematically review the evidence to determine the effectiveness of current interventions and inform subsequent guideline development.

The objective of this systematic review and meta-analysis is to investigate improvements in sedentary behaviour interventions for patients with CHD by integrating available evidence from randomised controlled trials and quasi-experimental studies.

Methods and analysisRegistration and study design

The systematic review protocol presented in this paper has been registered in PROSPERO (registration number CRD42023466985), and any future changes will be registered as amendments. We will complete and report the protocol according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) guidelines.18 Specific details are provided in table 1. The research questions are developed for inclusion criteria, exclusion criteria and search strategy based on the PICOS framework (population, intervention, control, outcome and study design).

Table 1

Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) 2015 checklist: recommended items to address in a systematic review protocol*

Eligibility criteria for selecting studiesTypes of study

We will include randomised controlled trials (RCTs) and quasi-experimental studies (including controlled clinical trials (CCTs) and before and after self-control studies) that have been published in peer-reviewed journals in English and Chinese. Reviews, cohort studies, study protocols and conference abstracts will be excluded.

Types of participant

Patients aged ≥18 years, who have had a myocardial infarction, who have undergone revascularisation (coronary artery bypass grafting, percutaneous coronary intervention), or who have angina pectoris or coronary artery disease defined by angiography will be considered. CHD, also known as coronary artery disease, ischaemic heart disease, or atherosclerotic heart disease, is a group of diseases that include stable angina, unstable angina, myocardial infarction and sudden coronary death. It is caused when the walls of coronary arteries become narrowed by a gradual build‐up of atheroma, allowing too little blood flow to the heart from the coronary arteries.19

Types of intervention

Interventions to reduce sedentary behaviour include but are not limited to interrupting sedentary or limiting screen time and combining other multicomponent lifestyle interventions such as physical activity, diet and sleep.

Types of control

The control group with the same diagnosis is not exposed to the intervention programme. In the before and after self-control studies, there was no control group.

Types of outcome

We will include studies that report time or sedentary behaviour patterns, ensuring a comprehensive approach to our research. Some studies reported prolonged sedentary behaviour (≥30 min/60 min/120 min) would also be considered. Outcome indicators measured by objective or subjective tools are included, further enhancing the thoroughness of our research.

Search methods for the identification of studies

A comprehensive search of PubMed, Medline, Embase, CINAHL, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, Scopus, CNKI, WAN FANG and VIP will be conducted from the inception of the databases until 31 December 2024. The search strategy for the electronic databases combined Medical Subject Headings and free-text words to represent the definitions of CHD, sedentary behaviour, RCTs and quasi-experimental studies. The detailed search strategies are available in table 2. Two authors (YY and QY) will complete the search process independently. Following the database search, a ‘snowball’ manual search will be conducted to retrieve additional eligible studies by reviewing the references of the included studies and existing systematic reviews related to the topic.

Table 2

Literature search strategy

Study selection

All retrieved records will be imported into EndNote X9 reference management software. After using the ‘Find Duplicates’ function to remove duplicate studies, two authors (YY and QZ) will independently assess the titles, the abstracts and the full text of studies using the selection criteria. The reasons for excluding studies will be detailed in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart (figure 1). If there is uncertainty regarding the inclusion of studies, consensus will be reached through discussion with the third author (LY).

Figure 1

Flow diagram of the article selection process.

Data extraction and management

Data extraction will be performed using a predesigned structured template. The following information will be extracted: (1) study information (the first author, year of publication, country and study design), (2) participant information (sample size, mean age, female ratio), (3) intervention details of the intervention and control groups, (4) duration of intervention and follow-up and (5) outcomes and sedentary behaviour measurement. We will contact the original authors for included studies with missing, uncertain, or incomplete information. Data will be extracted independently by two authors (YY and QY) and verified by a third author (QZ).

Methodological quality assessment

Two authors (YY and QY) will assess the quality of the included studies. RCTs will be appraised using the Revised Cochrane Risk of Bias Tool.20 For CCTs, the Risk of Bias In Non-Randomized Studies - of Interventions (ROBIN-I) tool will be used.21 The Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group will be used for studies without control groups.22 Disagreements can be resolved in consultation with the third author (LY).

Grading the quality of evidence

The Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines will be used to assess the level of evidence for sedentary behaviour outcomes.23 The body of evidence for the outcome indicators will be categorised as very low, low, moderate and high quality after assessing the risk of bias, consistency, directness of evidence, imprecision, and publication bias. Table 3 summarises GRADE’s approach to rating the quality of evidence.

Table 3

A summary of GRADE’s approach to rating quality of evidence

Data analysisData synthesis

Where we consider the studies to be sufficiently similar, we will conduct a meta-analysis by pooling the appropriate data using StataMP V.17 (64-bit) statistical software. Using the narrative method, we will analyse results that could not be quantitatively synthesised due to insufficient studies, missing data, or high heterogeneity of effect measures. For continuous variables, mean difference (MD) with 95% CI will be selected only if the unit of measurement and instruments are the same across trials; otherwise, standardised mean difference (SMD) with 95% CIs will be selected.24 Effect sizes for SMD will be categorised as small (<0.2), moderate (0.2–0.8), or large (>0.8) according to Cohen’s definition.25 P values <0.05 are considered statistically significant.

Assessment of heterogeneity

The I2 test will assess the level of heterogeneity between studies. If there is no substantial heterogeneity (I2 value ≤50%), we will use a fixed-effects model for the analysis. Otherwise, a random effects model will be used, which yields more conservative estimates of summary effects and is more recommended when there is unexplained heterogeneity across studies.25

Additional analysis for the primary outcome

Reading through previous meta-analyses of sedentary behaviour interventions in other populations,26 27 we were intrigued by the duration, type and other aspects of intervention studies in patients with CHD. If possible, we will conduct subgroup analyses based on demographic characteristics (eg, biological sex, race-ethnicity, age), intervention duration (≤3 months and ≥6 months), intervention types (electronic health and non-electronic health), intervention content (focusing only on sedentary behaviour and combining multicomponent lifestyle interventions) and measurement tools (objective and subjective) to explore their differential effects on sedentary behaviour. The funnel plot and Egger’s test will be used to assess the publication bias of original studies to be included in the review.28 In addition, if publication bias is detected, we will apply Duval and Tweedie’s Trim and Fill method to adjust for the bias.29 We will perform a sensitivity analysis by sequentially removing one study at a time to assess the impact of individual studies on the overall results.

Patient and public involvement

Neither patients nor the public will be directly involved in this study’s design, conduct, reporting or dissemination, as this systematic review will be based on publicly available research.

Discussion

Sedentary behaviour is associated with CHD-related metabolic risk factors, which can lead to insulin resistance, abnormal lipid metabolism, adipose tissue deposition and chronic inflammatory responses, thereby increasing the risk of recurrent cardiovascular events.30 31 Therefore, effective intervention methods are particularly importance, but the effectiveness of sedentary behaviour intervention studies conducted to date is unclear. Hence, this paper proposes a systematic review and meta-analysis protocol based on all available evidence from random clinical trials and quasi-experimental studies to comprehensively examine the effectiveness of existing interventions to reduce sedentary behaviour in patients with CHD.

In addition, subgroup analyses will be performed on the demographic characteristics (such as biological sex, race-ethnicity, and age), the type of intervention (electronic health and non-electronic health), the content of intervention (focusing only on sedentary behaviour and combining multicomponent lifestyle interventions), the duration of the intervention (≤3 months and ≥6 months) and measurement tools (objective and subjective). Conducting subgroup analyses by key demographic characteristics allows us to examine whether the effects of interventions on reducing sedentary behaviour in patients with CHD vary across different population groups. Given the potential for demographic factors to influence health outcomes, understanding these differences is essential for tailoring interventions to be more effective for specific subgroups. With the rapid development of technology, studies have shifted from offline face-to-face formats to online remote guidance, using electronic information and communication technologies to provide timely and convenient health services,32 such as the internet, smartphones, text messaging-based interventions and so on. A systematic review showed that digital technology interventions could improve sedentary behaviour in patients with cardiovascular disease.33 Then, we would like to emphasise the need for further research to validate the effectiveness of electronic and non-electronic interventions in improving sedentary behaviour in patients with CHD. This research is crucial in the face of the current challenges. Additionally, although research has shown that physical activity-focused programmes are not likely to yield meaningful reductions in sedentary time,34 studies being conducted to target sedentary behaviour as an adjunct to physical activity need to change. To further validate the efficacy of focusing only on sedentary behaviour for interventions, subgroup analyses will be conducted. Furthermore, the short-term and long-term effects of the intervention are a vital concern for any intervention. In a systematic review of interventions to improve sedentary behaviour in older adults, short-term effects were defined as ≤3 months and long-term effects as ≥6 months.26 Since patients with CHD are affected by declining cardiac function and physical fatigue, whether the sustained effects of interventions to improve sedentary behaviour will diminish over time requires further analysis. As far as measurement tools are concerned, subjective tools have the advantages of low cost and suitability for large samples, but their results are susceptible to patient recall bias and individual emotions. Objective tools are undoubtedly more accurate, but due to their more expensive price, some studies have used questionnaires for data collection.35 Therefore, it is meaningful to compare the use of different tools to measure the improvement of sedentary behaviour after the intervention.

Based on the above, this meta-analysis will conduct subgroup analyses in these five dimensions. It is anticipated that the results of subgroup analyses may inform clinical practice and the development of new trials of effective interventions, and complement future updates of guidelines on sedentary behaviour in patients with CHD. There are limitations to this review that should be considered. Unpublished articles and grey literature may be missed as we will be searching for relevant literature from databases. In addition, some intervention studies may be missed as the inclusion criteria will be limited to studies published in English and Chinese.

Ethics and dissemination

As this study does not involve human participants, ethical approval is not required. The results of the study will be disseminated through peer-reviewed journals or academic conferences.

Ethics statementsPatient consent for publication

Not applicable.

Acknowledgments

The authors thank the editors and experts for their valuable comments and guidance on the development of this article.