Introduction
Psychological risk factors have been acknowledged in the onset and progression of coronary heart disease (CHD) [
1]. Apart from the established detrimental effects of negative emotions, there’s a growing interest in the role of positive affect [
2]. Positive and negative affect can be considered as two independent systems, with positive affect not solely being the opposite of negative affect [
3], and the possibility that both types of affect can be present simultaneously [
4]. High positive affect can be described as a state of high energy, full concentration, and pleasurable engagement, whereas high negative affect can be described as the tendency to report distress, discomfort, dissatisfaction, and feelings of hopelessness over time and situations [
5].
Positive affect has been shown to be protective for incident hypertension [
6], whereas the influence on incident CHD is conflicting [
7,
8]. In established CHD, high levels of positive affect have been associated with less hospital readmissions [
9], whereas low levels of positive affect, also referred to as anhedonia, increase the risk of major clinical events in patients following coronary-artery stenting [
10]. Conflicting findings have been reported for associations between positive affect and survival in CHD (e.g. [
11‐
13]). Finally, positive affect has been shown to be associated with the production of early inflammatory markers in a middle-aged community sample [
14], and systolic blood pressure in healthy non-smoking men [
15].
In addition to positive affect, there is a growing interest in the role of personality factors in cardiovascular diseases (CVD). Type D personality (i.e., the combined tendency to experience negative emotions and to inhibit the expression of these emotions) is an emerging independent risk marker for clinical outcome and impaired patient-centred outcomes in cardiac disease (e.g., [
16‐
18]). However, Type D personality is not the only risk marker for impaired health outcomes in CVD. Within those patients categorized as non-Type D, there may also be some heterogeneity in terms of their risk of adverse health outcomes. Within those patients categorized as having no Type D personality, some subgroups of patients may also report lower levels of health outcomes.
Therefore, the aim of the current study was to determine whether non-Type D patients low on positive affect and Type D patients, report lower levels of health status when compared with non-Type D patients with high positive affect at 12-month follow-up in chronic heart failure (CHF).
Discussion
In the present study, we identified group of CHF patients reporting lower levels of health status at 12 months, namely those patients classified as having no Type D personality, but low on positive affect. This specific group of anhedonic non-Type D patients were shown to report lower levels of mental and physical health status, as well as more feelings of disability at 12-month follow-up, when compared with non-Type D patients high on positive affect. Furthermore, Type D patients were shown to report lower levels of health status, more cardiac symptoms, and more feelings of disability, when compared with non-Type D patients high on positive affect.
In this study the findings on the detrimental effects of Type D personality on patient-centered outcomes in CHF were confirmed [
30,
31]. Furthermore, we were able to identify a subgroup of anhedonic patients reporting lower levels of patient-centred outcomes. Post-hoc analyses demonstrated that these differences in patient-centred outcomes between groups were not only statistically relevant, but also clinically relevant, as effect sizes were overall large to very large (Cohen’s
d). CHF outpatients with a Type D personality reported lower levels of physical and mental health status at 12-month follow-up. These findings are in line with those of Hu and colleagues showing that older community dwelling persons diagnosed with chronic disease (i.e., arthritis, CVD, COPD, or diabetes) high on positive affect and low on negative affect had better mental and physical health status [
32]. Other studies that have also shown that lack of positive affect is associated with worse clinical outcome in patients with established CAD [
9,
10]. However, in the current study we did not have information on hard medical outcomes, like readmission rates and major adverse clinical events.
Apart from psychological factors, demographic and clinical characteristics were associated with impaired health outcomes in the current study. Overall, demographic and clinical factors were more likely to be related to physical health status than to mental health status at 12-months. For instance, we found female gender and having no partner to be associated with lower levels of physical health status, which has also been demonstrated by others [
33]. Nevertheless, the impact of marital status has not received considerable attention, but there are indications that single marital status and poor marital quality are associated with mortality in CHF.
Limitations of the current study must be acknowledged. First, the present study relied on self-reported outcomes. Nevertheless, all instruments administered are standardized measures that have been shown to be valid and reliable. In addition, the evaluation of patient-centred outcomes is of importance as there is a known discrepancy in physician and patient ratings of functioning, with physicians tending to underestimate the disabilities of patients [
34]. Further, the evaluation of health status is advocated by guidelines for treatment [
35,
36], since impaired health status is predictive of mortality in CHF [
37,
38] and generally patients report to prefer better health status over prolonged survival [
39]. Second, in the present study only patients visiting the outpatient clinic were approached for participation. Consequently, the results cannot be generalized to clinical heart failure samples. In this study, levels of positive affect were dichotomized. Future studies need to further explore whether a dose-response relationship exists between levels of positive affect and patient-centred outcomes. Further, from this study no conclusions regarding causality can be drawn, because of the study design. Finally, residual confounding might have affected the results from the present study, although we adjusted for various confounders in multivariable analyses. A strength of the current study comprises the use of both generic as well as cardiac disease-specific instruments for the evaluation of health outcomes. Future studies could include psychometrically sound CHF-specific health status questionnaires, to specifically evaluate health status in this particular patient group [
40].
From a clinical point of view, the present study underlines the importance of evaluating psychological risk factors, and in particular the clustering of psychological risk factors, as this enables the identification of different risk groups. This has also been advocated by others [
41]. Given that impaired health status has been associated with poor prognosis in CHF [
37], non-Type D patients low on positive affect and patients with a Type D personality should be identified in clinical practice, as they might need additional support and adjunctive intervention in order to experience health status levels comparable with other patients. Interventions might consist of improving skills to experience more positive affect by means of cognitive-behavioral therapy and mindfulness-based stress reduction. These types of psychological treatment have shown to be beneficial for improving positive affect in medically ill patients [
42,
43] and in older depressed patients at increased cardiovascular risk [
44].
In conclusion, we identified a specific group of CHF outpatients at risk for reporting impaired health outcomes, in the present study, namely those patients low on positive affect, and not classified as having a Type D personality. In addition, Type D patients also reported lower levels of health status, when compared with the reference group. Future studies are warranted to replicate the current and to determine the associations between positive affect and hard outcomes in CHF.
Acknowledgments
The authors gratefully thank Angélique A. Schiffer, PhD, for providing us with the data that were collected at the TweeSteden Ziekenhuis, Tilburg, The Netherlands. The present study was supported by a VICI-grant (453-04-004) from the Netherlands Organization for Scientific Research, The Hague, The Netherlands, to Johan Denollet, PhD.