Psychological factors play an important role in determining clinical outcomes in patients with cardiovascular disease (CVD). Much of the research has focused on the link between depression and poor cardiac outcomes, however, the influence of other psychological factors cannot be understated.

There is evidence that some positive psychological attributes such as optimism, positivity and well-being can affect health outcomes for CVD patients (DuBois et al., 2012). It has been suggested that patients with positive and optimistic attitudes towards their illness, treatment and prognosis will be more likely to experience better outcomes compared to others deficient in such positive constructs (Tindle et al., 2010).

This recent paper by DuBois and colleagues sought to systematically review and meta-analyse the current evidence around the impact of positive psychological constructs on clinical outcomes in CVD patients (DuBois et al., 2015).

Methods

Despite only searching two databases (PubMed and PsycINFO), the authors found 14,624 potential articles that were screened using the following inclusion criteria:

• Design: Prospective observational studies (at least a 12 week gap between baseline predictor measurement and outcome measure).
• Population: Established CVD patients (coronary heart disease (CAD), congestive heart failure, cardiac arrhythmia, cardiac surgery or heart transplant).
• Predictor: Measure of positive psychological construct (positive affect, optimism, hope, subjective well-being, gratitude, life satisfaction or life purpose).
• Outcome: Health-related outcome (mortality, rehospitalisation, adverse cardiac events, self-reported health status (i.e. health-related quality of life (HRQoL), function/disability)).
• Articles in English or Spanish.
• Publications from all years up until 2014.

The authors used the modified checklist from the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool to determine study quality; however, they chose not to report specific quality ratings in their paper.

In addition to the review, an exploratory random effects meta-analysis of selected studies was also done. Study heterogeneity was explored using chi-square analysis of heterogeneity (Q) and the I² statistic while publication bias was assessed with the Egger test.

Results

Study characteristics

A total of 30 studies met the inclusion criteria and were included in the narrative synthesis. The most common patient populations were stable (n=8) and unstable CAD (n=9) while the most common predictor variables were optimism (n=16), positive affect (n=11) and well-being (n=5). Mortality (n=9), rehospitalisation (n=5) and adverse cardiac events (n=5) were the most frequent health outcomes reported. Mean follow up was 32 months (ranging 3 months – 15 years) and all except 2 studies controlled for at least one key confounding factor (e.g. age, gender, health status, negative affect).

Narrative synthesis

There were 77 analyses reported in 30 studies, however, the authors chose only to include studies with over 100 participants to avoid including underpowered studies in their analysis. Therefore a total of 60 analyses from 23 studies were included.

• In unadjusted models, 39/60 analyses (65%) found a univariate association (p<.05) between a positive psychological construct and a health outcome.

• In adjusted models (controlling for any key confounding factors), 22/34 analyses (65%) found an independent association between a positive psychological construct and a health outcome.

• In adjusted models (controlling for depression or negative affect), 11/18 analyses (61%) found an independent association between a positive psychological construct and a health outcome.

Meta-analysis

Only studies with sufficient data and those that had mortality or rehospitalisation as outcomes were included in the meta-analysis (11/30 studies included). Here are the results broken down by health outcome:

Mortality

• Data from 6 studies found positive psychological constructs predicted reduced mortality in adjusted models (OR = 0.89, CI: 0.85 to 0.93, p < .001).
• There was little heterogeneity shown (Q = 1.64; p = .65; I² = 0.0%) or suggested publication bias (b= −04; p=.35).

Rehospitalisation

• Data from 3 studies found positive psychological constructs predicted reduced rehospitalisation in adjusted models (OR = 0.81, CI: 0.73 to 0.90, p < .001).
• There was little heterogeneity shown (Q = .41; p = .82; I² = 0.0%) or suggested publication bias (b= −.44; p = .70).

Combined outcome

• Data from 9 studies found positive psychological constructs predicted reduced rehospitalisation in adjusted models (OR = 0.88, CI: 0.84 to 0.91, p < .001).
• There was little heterogeneity shown (Q = 1.91; p = .86; I2 = 0.0%) or suggested publication bias (b = .82; p = .17).

Conclusions

Across multiple cardiac conditions, it seems that positive psychological constructs were significantly associated with health outcomes in approximately two thirds of analyses, irrespective of positive construct, cardiac disease-type and clinical outcome.

Furthermore, the results from the meta-analysis found that positive psychological constructs were associated with an estimated 11% and 19% reduction is the risk of mortality and rehospitalisation, respectively.

While there is certainly an association there between positive psychological qualities and health outcomes, this relationship is likely to be mediated by behaviour. CVD patients with positive and optimistic attitudes towards their condition would presumably be more likely to initiate and adhere to recommended health behaviours (e.g. balanced diet, increased exercise) that benefit cardiac outcomes.

The findings presented here suggest that gauging patients’ state of psychological well-being and encouraging positivity and optimism wherever possible could be a useful tool for healthcare professionals treating CVD patients.

Strengths

• Comprehensive and well written systematic review that provides value to the literature.
• Only included prospective cohort studies which is a strong design when wanting to look at the influence of prognostic factors on outcomes.
• Used rigorous methods for reporting data – Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines.

Limitations

• Meta-analysis included just 11 out of 30 studies.
• Limited search strategy, just two databases searched – PubMed & PsycINFO.
• Undertook quality assessment screening, however, did not assign or report quality scores – although the authors do attempt to justify why they have done this.

Links

Primary paper

DuBois, C. M., Lopez, O. V., Beale, E. E., Healy, B. C., Boehm, J. K., & Huffman, J. C. (2015). Relationships between positive psychological constructs and health outcomes in patients with cardiovascular disease: A systematic review. International Journal of Cardiology. [Abstract]

Other references

DuBois, C. M., Beach, S. R., Kashdan, T. B., Nyer, M. B., Park, E. R., Celano, C. M., & Huffman, J. C. (2012). Positive psychological attributes and cardiac outcomes: associations, mechanisms, and interventions. Psychosomatics,53(4), 303-318. [Abstract]

Tindle, H., Davis, E., & Kuller, L. (2010). Attitudes and cardiovascular disease. Maturitas, 67(2), 108-113. [Abstract]