Renee IJzerman

Chapter 1 outlines the framework of this thesis by situating cardiovascular disease (CVD) within the rising global burden of chronic (non-communicable) diseases, largely driven by unhealthy lifestyle behaviours (e.g., tobacco use and physical inactivity). Sustainable health behaviour change is essential for prevention and long-term management. Yet, it is difficult to initiate and maintain due to interacting psychological, social, and contextual determinants, and the tendency for intervention effects to diminish over time. The first chapter introduces two key behavioural strategies central to this thesis, namely motivating the initiation of lifestyle change through brief lifestyle advice, and supporting it through structured goal setting. Additionally, complex eHealth interventions are presented as a promising approach to support behaviour change, by using personalisation, monitoring and feedback, coaching, and integration into daily routines. As their real-world impact depends on successful implementation within routine care, implementation science is introduced to bridge the research-to-practice gap, with key frameworks described to guide implementation planning, determinant assessment, and evaluation. Furthermore, the BENEFIT programme is introduced as a public-private partnership (PPP)-based case study of a complex eHealth intervention that supports sustained healthy living amongst cardiac patients. The chapter also emphasises psychosocial challenges in CVD, including depression and anxiety, and positions (internet-based) cognitive behavioural therapy (iCBT) as a promising, evidence based component of holistic chronic disease management.

The main aims of this thesis are to: (i) advance knowledge on the initiation and maintenance of sustainable health behaviour change in patients with CVD, (ii) identify and address barriers and facilitators to implementing complex eHealth interventions in routine clinical care, particularly within PPPs, and (iii) integrate behavioural change and complex eHealth interventions into a holistic approach for chronic disease management, including psychosocial challenges in patients with CVD.

It presents four research questions: RQ1 How can brief lifestyle advice and the integration of life and health goals influence the intention to initiate and maintain lifestyle change in patients with CVD? (related to Aim 1), RQ2 How can implementation science be applied to design and implement a theory-based, practice-tailored implementation strategy for implementing complex eHealth interventions into routine clinical care? (related to Aim 2), RQ3 How can implementation science be applied to identify barriers and facilitators influencing the implementation of complex eHealth interventions into routine clinical care? (related to Aim 2), and RQ4 How can implementation science be applied to integrate behavioural change and complex eHealth interventions into a holistic approach for chronic disease management, addressing psychosocial challenges faced by patients with CVD? (related to Aim 3).

Chapter 2 aims to advance knowledge on the initiation and maintenance of sustainable health behaviour change in patients with CVD (Aim 1). It explores how the source of the message (cardiologist vs physiotherapist) and the framing of the message (gain vs loss) of brief lifestyle advice may influence intention-to-change-lifestyle amongst patients with CVD. In an online experimental study with 636 patients with CVD, it was found that their intention-to-change-lifestyle was significantly higher when they received advice from the cardiologist. However, participants generally demonstrated a positive intention-to-change lifestyle following the advice received from both the cardiologist and physiotherapist. The framing of the advice, whether it focused on the benefits of a healthy lifestyle (gain-frame) or the risks of an unhealthy one (loss-frame), appeared equally effective on their intention to-change-lifestyle. Nevertheless, gain-framed messages were much better recalled by participants compared to loss-framed messages: only 9% of patients remembered the risks (loss), whilst 89% recalled the benefits (gain). Overall, these findings indicate that brief, positively framed lifestyle advice from a credible professional enhances motivation for health behaviour change. The next question is how this can be nurtured through personalised goal setting strategies.

Chapter 3 also aims to advance knowledge on the initiation and maintenance of sustainable health behaviour change in patients with CVD (Aim 1). The study explores patients’ preferences in health and life goals, examining how linking these goals affects their intention to-change-lifestyle. Additionally, it investigated socio-demographic and health-related factors that may influence their intention-to-change-lifestyle. Conducted as a second online experimental study amongst 629 participants, patients with CVD were randomised into two conditions: the health-goal group (HG) or the life-and-health-goal group (LHG). The first condition, HG, set a health goal, whilst the second condition, LHG, established a life goal and then a health goal to support it. Then, intention-to-change-lifestyle was analysed along with secondary outcomes. Exercise-related health goals were most chosen in both goal setting groups, but stress management goals were significantly more prevalent when life goals were linked to health goals. Linking life goals to health goals did not significantly influence CVD patients’ intention-to-change-lifestyle. However, lower- and medium-educated participants showed a significantly higher intention-to-change-lifestyle when life goals were linked to health goals. Moreover, experiencing meaning in life was shown to have a significant positive impact on intention-to-change-lifestyle. These findings underscore the importance of personalised goal setting within cardiac care practice, particularly for individuals with CVD with lower and medium education levels, and highlight the benefits of integrating life goals with health goals to enhance their motivation and adherence to lifestyle changes. Our results also emphasise the critical need to consider and anticipate socio demographic factors when developing and enrolling interventions within healthcare.

Chapter 4 contributes towards the identification and addressing of the multifaceted barriers and facilitators to implementing complex eHealth interventions in clinical practice, particularly within PPPs (Aim 2). A detailed method for developing, evaluating, and refining an implementation strategy for complex eHealth interventions in routine practice is presented. The BENEFIT programme, a complex eHealth intervention developed by the BENEFIT consortium, a PPP to support healthy living in patients with CVD, serves as a case study to describe the development process of the strategy. Through six iterative phases alternating between theory and practice, an initial strategy was developed based on a process model and evaluation framework well-known within implementation science, namely the Implementation of Change Model and the RE-AIM framework. Input from key stakeholders was gathered to refine the strategy, followed by pilot-testing within clinical practice after some improvements were made. Key challenges hindering implementation were subsequently identified, such as the impracticality of implementing all programme features in certain organisations, overwhelming initial strategy presentation, unclear role assignments, and lack of employee involvement in decision-making. These barriers were subsequently mapped onto relevant domains and constructs of the Consolidated Framework for Implementation Research (CFIR). The purpose of this was to interpret the barriers as determinants of implementation success and, on that basis, to select and tailor targeted implementation strategies. These evidence-based recommendations were then used to strengthen the strategy. The result was an implementation strategy that was both scientifically grounded and practically feasible, aligning with stakeholders’ needs and the context in which it was to be applied. This study highlights the importance of a multifaceted and adaptable implementation strategy approach, emphasising thorough communication, stakeholder involvement, and continuous refinement based on practical feedback. The findings provide a valuable blueprint for researchers and implementation experts aiming to implement complex eHealth interventions sustainably. It also underscores the need for evidence-based and practice-oriented strategies to ensure successful and long-term adoption in clinical settings. However, developing an implementation strategy is only the first step; its real-world usage depends on how organisations and stakeholders respond to the strategy in routine clinical practice. Therefore, the next chapter evaluates the real-world implementation process that was executed.

Chapter 5 also contributes towards the identification and addressing of the multifaceted barriers and facilitators to implementing complex eHealth interventions in clinical practice, particularly within PPPs (Aim 2). It presents a comprehensive evaluation of the barriers and facilitators encountered whilst implementing the BENEFIT programme. Using the CFIR as a guiding framework, several key facilitators for successful implementation were identified. These included the adaptability of the programme, team communication and planning, digital healthcare needs, dedicated PPP leadership, and the PPP’s meeting structure and ability to quickly adapt the implementation strategy. Barriers were specific PPP challenges, such as frequently changing roles, vague responsibilities, and staffing shortages, along with disruptions in the workplace, ineffective IT integration, and vague implementation objectives across cardiac rehabilitation (CR) sites. These findings highlight the challenges involved in implementing complex eHealth interventions within healthcare systems, and emphasise the necessity for a multifaceted and adaptable approach. Overall, the findings stress the importance of a tailored and coordinated implementation approach that aligns with the dynamic nature of PPPs and their healthcare environments. The insights may inform practical strategies for future PPP-led implementations, ultimately supporting more effective chronic disease care and better patient outcomes.

Chapter 6 focuses on the integration of behavioural change and complex eHealth interventions into a holistic approach for chronic disease management, including psychosocial challenges faced by patients with CVD (Aim 3). It explores the adoption of online therapy, specifically, internet-based Cognitive Behavioural Therapy (iCBT), amongst psychologists in medical hospitals, using the Unified Theory of Acceptance and Use of Technology (UTAUT) model. Although iCBT’s potential to improve self-management and adaptation to chronic illnesses is acknowledged, its actual usage amongst psychologists remains limited. During the time of research, 15.9% of psychologists used iCBT in their practice, whilst 16.8% had access to it, and 21.5% intended to use it within the following year. Key determinants influencing behavioural intention towards iCBT usage included performance expectancy, effort expectancy, and facilitating conditions, collectively explaining 49% of the variance in behavioural intention amongst non-users. Social influence did not significantly impact behavioural intention. These findings highlight the gap between intention and actual use of iCBT, underscoring the need to enhance education and training on iCBT, increase its availability within practice, and improve its integration into the daily workflow of psychologists. Strengthening these factors may contribute to better management of chronic diseases and improved patient outcomes.

Finally, Chapter 7 synthesises the findings of this thesis and situates them within the broader context of patient-centred cardiovascular care. It argues that meaningful reductions in CVD burden require a holistic, integrated approach that links sustainable lifestyle change, the successful implementation of complex eHealth interventions, and psychosocial support. Drawing on the findings, six lessons for practice and policy were formulated: (i) brief, positively framed lifestyle advice from trusted sources drives behavioural change, and gain-framed messages are particularly memorable, (ii) timing and personalisation matter, yet intention alone is insufficient and is constrained by the (often invisible) work of being a patient, including stress, competing responsibilities, and limited capacity to translate intention into action, (iii) structural inequality must be addressed to avoid widening health gaps, because without equity-sensitive communication and design (including plain language, teach-back techniques, motivational interviewing, and personalised goal setting), interventions may exacerbate rather than reduce health inequality, (iv) implementation succeeds with adaptability, stakeholder co-design, and role clarity, (v) PPPs offer essential opportunities for innovation but require formalised governance frameworks, shared ownership, and implementation skills to manage role ambiguity, power dynamics, and competing stakeholder interests, and (vi) innovations such as complex eHealth interventions and online therapy (e.g. iCBT) must be embedded in clinical workflows and supported by training, alongside efforts to strengthen digital inclusion.

It is advised that future research focusses on (i) behavioural maintenance and long-term impact, using longitudinal designs and objective metrics such as wearable-device data, (ii) reducing health disparities through tailored design, including user-centred approaches for socioeconomically vulnerable groups and by paying attention to the broader social determinants of health, (iii) embedding sustainability through health economic evaluations, including cost-effectiveness and reimbursement structures, (iv) optimising implementation in diverse healthcare contexts, including adaptive implementation models for low-resource settings and improved PPP governance, and (v) moving beyond individual responsibility by studying and implementing systemic and policy change to reform health-shaping environments.

Overall, the thesis concludes that ‘heartwiring’ change requires an ecosystem that aligns behaviour change mechanisms, implementation strategies and organisational conditions (including workflow integration and training), and psychosocial care with real-world contexts and equity considerations. It also recognises that even the best, well-supported individual-level interventions remain constrained without broader environmental and policy reform.