Illness perception as a mediator of disease severity, psychological stress, and health-related quality of life in patients with acute coronary syndrome: a commentary

This invited commentary refers to ‘Relationships between disease severity, psychological stress, and health-related quality of life among patients with acute coronary syndrome: Mediation of illness perception’, by G. Zhang et al., https://doi.org/10.1093/eurjcn/zvae030. Lower health-related quality of life (HRQL) is often experienced by patients with acute coronary syndrome (ACS), the extent of which may be related to disease severity and psychological stress.1 Illness perception, an individual’s beliefs, and expectations regarding one’s own illness have also been shown to be a predictor of psychosocial and clinical outcomes after a cardiac event.2 Illness perception is a core concept of the Common-Sense Model of Self-Regulation (CSM) used to help understand illness self-management.3 The importance of positive illness perception has been demonstrated in promoting positive behaviour change and recovery in patients with ACS. Understanding the role of illness perception in relation to disease severity, psychological stress, and HRQL can facilitate the provision of more individualized care and identify patients who might need additional support. In the paper by Zhang et al.,4 the authors focused on investigating the relationships between disease severity, psychological stress, and HRQL and whether these relationships are mediated by illness perception, in 405 Chinese patients with ACS. After controlling for sociodemographic and clinical covariates, higher levels of disease severity and psychological stress were associated with lower HRQL. Interestingly, after adding illness perception into the regression models, the direct relationships between disease severity and psychological stress with HRQL resulted in non-significance, suggesting that these factors do not directly affect HRQL. When illness perception was added as a factor to the structural equation modelling analysis, the mediation (indirect) effects accounted for 45.95% and 65.79% of the total effects for disease severity and psychological stress, respectively, indicating the important effect of the way patients perceive their illness. What this study adds is that patients’ own perception of their disease, regardless of actual physiological and psychological symptoms and states, may be an area amenable to change and therefore a potential key to improving their HRQL. While HRQL is generally understood to be influenced by physical and psychological factors, identifying how a patient perceives their disease (e.g. via routine screening) provides opportunities for interventions aimed at promoting healthier coping responses to reduce the perceived threat of illness. For instance, clinicians may provide information, explain disease processes and treatments, provide answers, and explore concerns and expectations, in theory, all affecting the patient’s mindset. However, one important issue that needs to be raised is that illness perception, although modifiable, includes strongly held set of beliefs and identity reflected in one’s attitudes that can be difficult to change. It is currently not known if, and to what extent, these relatively episodic interventions indeed influence mindset factors. Another key consideration is the influence of a patients’ social support and the relationship to illness perception, psychological stress, and HRQL.5 For example, social support, left ventricular ejection fraction (LVEF) (as a measurement of illness severity), and illness perception have all been suggested to be significant predictors of higher HRQL at 3 months post-ACS.6 Other research has noted a relationship between LVEF and depression in cardiovascular disease patients, which is mediated by perceived social support and illness perception.7 Social isolation and low social support predict incident cardiovascular disease events, whereas the presence of a partner after ACS is associated with improvements in lifestyle-related risk factors and better ACS prognosis vs. single patients.8 Moreover, this relationship is often reciprocal, with illness perception impacting social support delivered by spouses and partners having a significant influence on how a condition is perceived. As such, social support acts as a ‘buffer’ to mitigate the negative impact of stress following ACS. Similarly, treatment adherence, particularly medication adherence, was not assessed and is believed to be a potential confounder influencing HRQL in patients with ACS. Adherence to recommended guidelines and long-term secondary preventative therapies is fundamental to improving long-term outcomes in patients with ACS. However, a recent review has reported that almost 30% of patients with ACS discontinued one or more medications within 90 days of diagnosis and adherence decreased to 50–60% at 1 year post-discharge.9 Furthermore, a positive association has been reported between treatment adherence and HRQL among patients with ACS (r = 0.169, P < 0.01).10 On the other hand, treatment non-adherence in patients with ACS can also have a psychological effect on their HRQL. This study determined that the influence of these factors was mediated by illness perception and potentially by social support. Moreover, this commentary presents a multitude of factors can negatively affect HRQL in patients with ACS including disease severity and psychological stress. Addressing these variables may require complex interventions in the clinical setting. Secondary prevention focusing on promoting positive illness perception and psychological well-being must be prioritized in this population to improve HRQL and cardiovascular health. Factors such as social support and medication adherence should be also taken into consideration in future studies. Longitudinal modelling and trial testing should be considered in future research to measure the long-term effect of complex secondary prevention interventions that improve HRQL in this patient group. No new data were generated or analysed in support of this research.