Introduction
Cardiac rehabilitation is a comprehensive program designed to improve the cardiac and overall functional status affected by cardiovascular diseases, prevent recurrent cardiovascular events, enhance quality of life, and facilitate reintegration into normal social life [
1]. As a priority recommendation, exercise-based cardiac rehabilitation significantly improves cardiac function and prognosis in patients with coronary artery disease [
2,
3]. However, the persistent nature of heart diseases, combined with logistical challenges such as transportation barriers, means that institution-based CR may be financially taxing and time-consuming for patients [
4]. As a solution, Home-Based Cardiac Rehabilitation (HBCR) provides a cost-effective and accessible alternative model that brings similar improvements in reducting cardiovascular risk, promoting mental and spiritual well-being, enhancing cardiac function and prognosis, and improving the quality of life for patients [
5‐
9].
HBCR management includes five key components: medication adherence, physical activity, healthy eating, psychological support, and smoking cessation [
10]. Psychological management, particularly addressing depression, is crucial for the effectiveness of HBCR [
10]. Studies indicate that depression affects approximately 20–30% of cardiac patients, with even higher rates observed in those undergoing cardiac rehabilitation [
11,
12]. Depression symptoms (e.g., low mood, lack of motivation, and fatigue) can reduce adherence to rehabilitation exercises and medication, increasing the risk of cardiovascular readmissions [
13,
14]. Moreover, depression can severely impact mental health and quality of life, exacerbating cardiac symptoms such as chest pain and dyspnea [
15,
16]. Therefore, managing depression in coronary artery disease patients is a critical focus in HBCR. Effective identification and management of depression not only improve psychological health but also enhance rehabilitation outcomes and reduce the risk of adverse cardiovascular events.
Depression in coronary artery disease patients undergoing HBCR is dynamic, evolving over time and influenced by various factors, unfolding through different patterns or trajectories, and closely related to adverse cardiovascular outcomes [
17]. The heterogeneity of depression trajectories underscores the urgent need to identify key influencing factors to facilitate targeted interventions. In terms of patient care, understanding the significance of depression trajectories not only aids in comprehending the psychological health status of patients but also provides a scientific basis for developing personalized intervention strategies, thereby improving overall health management and rehabilitation outcomes. Additionally, the implications of this research for healthcare systems are equally important; by optimizing depression management strategies, it can enhance resource allocation efficiency, reduce cardiovascular readmission rates, and ultimately improve patients’ quality of life and satisfaction. Current methods for assessing depression in coronary artery disease patients during HBCR primarily rely on one-time cross-sectional evaluations. While these methods capture a snapshot of depressive symptoms, they fail to account for the dynamic nature of depression over time. This limitation highlights a critical gap in our ability to assess and identify the prevalence and key predictors of depression in coronary artery disease patients.
To bridge this gap, this study aimed to explore the depression trajectories of coronary heart disease patients during HBCR, identify trajectories associated with cardiovascular readmission, and integrate them into a heterogeneous depression trajectory while examining its predictors. The study hypothesizes that different depression trajectories are significantly associated with the risk of cardiovascular readmission, and that factors such as education level, number of chronic diseases, resilience, social support, and anxiety are independent predictors of depression trajectories. The research questions include: (1) What types of depression trajectories are present in coronary artery disease patients during HBCR? (2) How do these depression trajectories impact the risk of cardiovascular readmission? (3) What factors play a critical role in different depression trajectories? By highlighting the diversity in depression trajectories and their predictive value for adverse outcomes, this study aims to provide a foundation for personalized psychological interventions and theoretical support for future research on depression management within cardiovascular rehabilitation.
Discussion
In this study, depression in coronary artery disease patients exhibited significant heterogeneity during HBCR, which could be categorized into four distinct trajectory types: sustained no depression, delayed onset, low U-shaped depression, and sustained depression. Understanding these depression trajectories is crucial for clinical practice and patient outcomes, as they not only reveal the dynamic changes and heterogeneity of depressive symptoms but also closely associate with the risk of cardiovascular readmission, particularly in the delayed onset and sustained depression groups, collectively termed the heterogeneous depression trajectory. Notably, education level, number of chronic diseases, resilience, social support, and anxiety were independent predictors of the heterogeneous depression trajectory. These findings not only reveal the dynamic changes, heterogeneity, and potential influencing factors of depression during HBCR in coronary artery disease patients but also underscore the importance of early identification and personalized management of depression. By better understanding these trajectories, we can provide a scientific basis for developing more effective intervention strategies, which can improve patients’ psychological health, rehabilitation outcomes, and reduce the risk of cardiovascular readmission.
This study revealed significant trajectory heterogeneity in depression among coronary artery disease patients during HBCR, with different trajectory types exhibiting distinct characteristics in psychological states and disease progression. These trajectory patterns reflect the dynamic changes in depression, emphasizing the importance of continuous monitoring of depression during rehabilitation [
24]. Particularly, the peak in depression at the fifth month may be associated with various challenges and pressures faced by patients in the later stages of rehabilitation, such as the complexity of rehabilitation plans, difficulty in long-term adherence, and potential lack of social support [
25,
26]. The findings of the delayed onset and low U-shaped depression groups further highlight the potential volatility and delayed effects of depression. These patients may not exhibit significant depression in the early stages, but over time, symptoms gradually emerge or recur. This delayed effect might be related to patients’ initial adaptation to rehabilitation, gradually increasing physical burden, and the accumulation of long-term psychological stress [
27,
28]. Patients in the sustained depression group consistently exhibited high levels of depression throughout the rehabilitation period, indicating that these patients might require more intensive and personalized psychological interventions. The persistent presence of depression not only reduces adherence to rehabilitation plans but also increases the risk of cardiovascular readmission, further impacting overall rehabilitation outcomes [
29,
30].
Our study found that the depression trajectories significantly influenced the risk of cardiovascular readmission in coronary artery disease patients during HBCR, particularly in the sustained depression and delayed onset groups. These findings highlight the potential negative impact of depression on cardiac rehabilitation outcomes and emphasize the importance of screening and personalized psychological interventions [
31]. Kaplan-Meier survival curves and Cox proportional hazards regression analysis both indicated that patients in the sustained depression group had a significantly higher risk of cardiovascular readmission compared to other groups. This suggests that persistent depression may lead to greater psychological and physiological stress during rehabilitation, thereby increasing the incidence of cardiovascular events [
32]. The high readmission risk in the delayed onset group is also noteworthy, indicating that depression not promptly identified and managed in the early stages of rehabilitation may gradually worsen and adversely affect cardiovascular health [
33]. Combining Groups 2 and 4 into the “Heterogeneous Depression Trajectory” further underscores the heterogeneous impact of different depression trajectory types on patient prognosis. Approximately 27% of patients belong to this category, suggesting a need for special attention to this group with significant changes in depression in clinical practice. Early identification of these high-risk patients and providing appropriate psychological support and interventions can not only improve their psychological health but also potentially reduce the incidence of cardiovascular readmissions and enhance overall rehabilitation outcomes.
The study identified education level, number of chronic diseases, resilience, social support, and anxiety as independent predictors of heterogeneous depression trajectory in coronary artery disease patients during HBCR. These results provide new perspectives for understanding the formation mechanisms of depression trajectories and offer a scientific basis for developing clinical intervention strategies. Firstly, compared to primary education, patients with secondary and higher education levels had a significantly lower risk of heterogeneous depression trajectory. This finding may reflect the advantages of higher education levels in health knowledge, self-management skills, and resource acquisition, enabling patients to cope more effectively with the challenges and pressures of cardiac rehabilitation [
34,
35]. Secondly, the relationship between the number of chronic diseases and depression trajectories suggests that patients with more chronic diseases face a higher risk of depression. This result implies that patients with multiple chronic diseases may experience greater disease burden, leading to increased psychological stress and a higher incidence of depression [
36]. Therefore, during rehabilitation, special attention should be given to these high-risk patients, providing comprehensive management and support through multidisciplinary collaboration. The findings on resilience and social support further emphasize the crucial role of psychological and social factors in managing depression. Patients with high resilience and social support levels had significantly lower risks of depression during rehabilitation, indicating that enhancing patients’ psychological resilience and social support networks is an effective intervention strategy [
37,
38]. Psychological resilience helps patients cope better with adversity, while strong social support provides emotional and practical assistance, alleviating feelings of loneliness and stress [
37,
39]. Finally, anxiety, whether mild, moderate, or severe, significantly increased the risk of heterogeneous depression trajectory. This finding indicates a close link between anxiety and depression, where the presence of anxiety symptoms exacerbates depression. Therefore, early identification and management of anxiety symptoms during rehabilitation are crucial and can be addressed through psychological counseling, medication, and other interventions to alleviate patients’ anxiety and depression.
Limitations
Despite the important insights provided by this study, several limitations need to be considered. First, this study was conducted at a single center in mainland China, which may restrict the generalizability of the findings. The specific demographics and healthcare context of this center may not reflect the diversity of other populations or healthcare settings. Future research should aim to replicate this study in multiple centers and varied populations to enhance the external validity and applicability of the findings. Second, the assessment of depression relied on self-reported questionnaires, which may introduce reporting bias, with patients potentially underestimating or overestimating their depression levels for various reasons. To reduce this bias, future studies should consider incorporating objective psychological assessment tools and clinical interviews. Additionally, we would like to emphasize that it is not possible to infer causal relationships due to the observational nature of the study. Lastly, although this study explored multiple potential predictors, it did not include all possible factors influencing depression trajectories, such as socioeconomic status, family support structure, and patients’ lifestyle habits. Future research should further investigate the impact of these factors to comprehensively understand the dynamic changes and predictors of depression in coronary artery disease patients.
Conclusion
This study revealed significant heterogeneity and independent predictors of depression trajectories in coronary artery disease patients during HBCR. These findings emphasize the importance of continuous psychological assessment and personalized management during rehabilitation. Specifically, education level, number of chronic diseases, resilience, social support, and anxiety are crucial factors influencing depression trajectories. Therefore, in future research, early identification and management of these high-risk factors could lead to more effective intervention strategies, improving patients’ psychological health, reducing the risk of cardiovascular readmission, and enhancing overall rehabilitation outcomes.
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