SIGN 97: Risk estimation and the prevention of cardiovascular disease

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11 Psychological issues

11.1 The impact of stress, psychological distress and personality variables on cardiovascular risk

11.1.1 Stress

Stress is perceived by the majority of cardiac patients to have been an important cause of their heart disease. This belief is also common among the general public, and confusion exists among health professionals as to its role in the development of and outcome with CHD. While stress is a commonly used term it has no precise definition and cannot be readily measured. Stress is generally accepted to include a number of components which are measurable, and have been studied, including:

A review of systematic reviews undertaken by an Expert Working Group of the National Heart Foundation of Australia identified 15 reviews showing strong and consistent evidence that depression and social isolation or lack of quality social support are independent risk factors for the development of and prognosis with CHD.277 The largest of these reviews provides strong and consistent evidence for both these factors but also evidence that aspects of work-related stress may be associated with increased risk.278 Evidence level 2++

The review concluded that depression, social isolation and lack of social support are significant risk factors for CHD and are independent of conventional risk factors such as smoking, hypercholesterolaemia and hypertension with a similar strength of association (one to two-fold increased risk of developing CHD with minor depression and three to five-fold increase with majordepression).Social isolation/lack of quality social support is also of a clinically significant magnitude (two to three-fold increased risk of developing CHD and three to five-fold increased risk of death in patients with CHD). Evidence level 2++

There is no clear evidence to suggest that treating depression is effective in reducing risk. Increased attention to conventional risk factors in patients with depression may be appropriate.279 Further research is necessary to determine the underlying mechanisms accounting for this increased risk and to determine which interventions are effective in treating this risk. Evidence level 2++

There is consistent evidence that catastrophic life events of a highly stressful nature such as earthquakes or terrorist attacks and, to a lesser degree, bereavement are associated with increased cardiac risk, but no consistent evidence for chronic life stress including stress in the workplace.277 The implications of these findings for the individual patient are not clear.

There is no consistent evidence to suggest that anxiety or panic attacks are risk factors for CHD. Neither is there clear evidence to support the view that stress at work increases the risk of developing or dying from CHD. There is lack of precision in defining 'work stress' and consistency of measurement in studies. There was some evidence that CHD risk in relation to work was related to individual personality factors such as coping styles, availability of support and other psychosocial factors rather than work specific characteristics. While early studies suggested that personality traits such as type A behaviour or hostility might be associated with increased cardiovascular risk, there is now clear evidence that this is not the case.278 Evidence level 2++

The INTERHEART study reported on risk factors, including psychosocial factors, for 11,119 MI cases and 13,648 controls across 52 countries.280 Composite variables of subjective stress (home, work, and financial stress, low self-efficacy and self reported retrospective rating of depression) appeared to be associated with increased risk of developing an acute MI across gender, nationality, ethnic groups, and to be independent of smoking and socioeconomic status. There are some major concerns regarding the methods of measurement of stress in this study, which was undertaken in a non-standardised way and retrospectively relying on patient memory and perception over the previous 12 months. It does indicate that some undefined elements of stress contribute to increased risk of cardiac events across cultures. Evidence level 1+

BDepression and social isolation or lack of quality social support are risk factors for the development of and prognosis with coronary heart disease and should be taken into account when assessing individual risk.

Further research is necessary to determine the underlying mechanisms accounting for this increased risk and to determine the most effective interventions for treatment.

11.2 Psychological interventions

11.2.1 Stress management

Stress management is defined as "using cognitive behavioural strategies to reduce or manage stress". Relaxation alone or combined with cognitive or problem solving techniques is included inthisdefinition.Venting feelings and/or discussion only or counselling and cognitive behaviour therapy for clinical depression are excluded.

One Cochrane review of psychological interventions for coronary heart disease examined stress management (SM) techniques.281 Thirty six trials with 12,841 patients were included. Of these, 18 (5,242 patients) were SM trials. The quality of many trials was poor with the majority not reporting adequate concealment of allocation, and only six used blinded outcome assessors.

Patients were not selected for level of stress, anxiety or depression etc. Measures of outcome for mood were by self-report on a continuous scale, rather than using cut-offs to identify those who were clinically depressed.

There was a reduction by 22% in the number of non-fatal reinfarctions in the intervention group (OR 0.78, 95% CI 0.67 to 0.90), but the two largest trials (with 4,809 patients randomised) were null for this outcome, and there was statistical evidence of publication bias. Overall psychological interventions showed no evidence of effect on total or cardiac mortality, but did show small reductions in anxiety and depression in patients with CHD (p<0.025). Similar results were seen for SM interventions when considered separately. The poor quality of trials, considerable heterogeneity observed between trials and evidence of significant publication bias make the pooled finding of a reduction in non-fatal myocardial infarction insecure. Evidence level 1++

AStress management training is not recommended as a technique to reduce coronary heart disease mortality or morbidity or conventional risk factors. It may have a role in improving patients? mood, including depressed mood.

11.2.2 Motivational Interviewing, Health Behaviour Change and Stages of Change model

Clinical approaches to helping people change behaviour include use of cognitive behaviour therapy, motivational interviewing, stages of change approach, counselling and education. Research has focussed on identifying models to explain the intention to change and behaviour relationship eg Theory of Planned Behaviour,282 and also examined attributions and health beliefs (see SIGN guideline 57 on cardiac rehabilitation and SIGN guideline 96 on management of stable angina).76,283

Interventions

Cognitive behaviour therapy is a structured therapy addressing individuals? core beliefs, assumptions, thinking patterns and behaviour.

The stages of change model284 and motivational interviewing285 are different but related approaches to helping people change behaviour. Stages of change based approaches propose that tailoring interventions to the individual?s readiness to change is more effective than using the same approach for all. There is less clarity about the specific nature of the therapeutic strategies to be used at each stage. Motivational interviewing and its adaptations (including health behaviour change) use structured strategies to help minimise resistance and elicit desire to change from within the individual.286

Cognitive Behaviour Therapy

Cognitive behaviour therapy (CBT) has been shown to be effective in patients with a wide range of conditions, including anxiety, depression, post-traumatic stress disorder and medical conditions.287 Use of this approach with cardiac patients and other physical health problems (chronic fatigue and chronic pain) as part of an educational and rehabilitation programme has addressed beliefs and attributions and used goal setting and pacing principles to shape the desired behaviour. Studies note positive outcomes in exercise, activities and mood.288-291 Evidence level 1++, 4

Stages of Change model

A high quality systematic review of effectiveness of interventions based on a ?stages of change ? approach, reviewed 37 RCTs (12 aimed at smoking cessation, seven on promotion of physical activity, five ondietary change and six o nmultiple life style changes).292 There was little evidence to suggest that stage-based interventions are more effective compared to non-stage based interventions, no intervention or usual care. Of 37 trials, 17 showed no significant differences between groups, eight showed mixed effects and ten trials showed effects in favour of a stage based intervention. A further meta-analysis looked specifically at studies using these approaches for smoking cessation, and found interventions based on the stages of change model were no more effective than interventions based on other models or no intervention.293 Methodological shortcomings of the studies reviewed contribute to the conclusion that current research does not demonstrate effectiveness of stages of change based interventions in reducing risk factors for CHD. Evidence level 1++

Motivational Interviewing

Two meta-analyses and a systematic review of motivational interviewing have examined the efficacy of this approach. One meta-analysis reviewed 30 trials covering alcohol, drug misuse, exercise and diet problems, smoking cessation and HIV/risk behaviour.294 Adaptations of motivational interviewing were equivalent to other active treatments and superior to no- treatment or placebo for problems involving alcohol, drugs, diet and exercise, though not for smoking cessation and HIV risk behaviour. There were higher effect sizes for diet and exercise studies. Effect sizes for motivational interviewing were equivalent to other psychotherapeutic treatments (0.50), with motivational interviewing being delivered in fewer sessions. The lack of evidence for smoking may be due to the small number of studies meeting inclusion criteria. Training, supervision and competence of therapist were addressed. Evidence level 2+

Another meta-analysis reviewed 72 studies (including 31 on alcohol issues, six on smoking cessation, five on treatment compliance and four on diet and exercise).295 There was wide variability in effect sizes across studies and problem areas (across all studies mean effect size was 0.77, 95% CI 0.35-1.19). Effect size was higher when treatment was not manual based. The effect of motivational interviewing was seen early on and tended to diminish over 12 months follow up. The use of motivational interviewing was effective in areas relevant to the prevention of CHD (diet, exercise effect size 0.78, 95% CI 0.41 to 1.16 across all follow up points, alcohol effect size 0.26 95% CI 0.18 to 0.33 across all follow up points), but not effective in smoking. A study identified that level of 'commitment talk' from the client was a strong predictor of change.296 Evidence level 2+

Adding motivational interviewing to other treatment approaches maintained or improved its effect over 12 months (effect size 0.60). As motivational interviewing may be added to a cardiac rehabilitation intervention in CHD patients, this may increase its benefit.

A systematic review looked at eight studies, including four RCTs, in patients with diabetes, asthma, hyperlipidaemia, hypertension and CHD. The majority of RCTs and studies found positive effects of motivational interviewing on psychological, physiological and lifestyle change outcomes, but the quality of studies overall prevented meta-analysis and the drawing of firm conclusions about effectiveness. Problems included sample size, lack of power, disparate outcomes and poorly defined therapy and therapist training.297 Evidence level 1+

Therapist training, skill and competence

The effectiveness of any intervention depends on the training and competence of the therapist.One study indicated that therapist proficiency was best gained by adding specific feedback and/or coaching to workshop participation.298 The Department of Health guideline on treatment choice in psychological therapies and counselling, recommends that psychological therapies including CBT, more complex problems, and those where patients are poorly motivated, require the more skilful therapist.287 Evidence level 1+, 4

Summary

The use of CBT in addressing beliefs and structured behaviour change is effective in increasing activities and improving mood in CHD patients and other groups. Motivational interviewing has a strong potential to effect change in physical health behaviour and demonstrates effectiveness in addiction behaviours. Use of these skills can be effective in increasing patient engagement in other active therapy.

ACognitive behaviour therapy should be considered for increasing physical function and improving mood in patients with coronary heart disease.

AUse of the stages of change model alone is not recommended as a method for changing the health behaviour of individuals with coronary heart disease.

BMotivational interviewing should be considered in patients with cardiovascular disease who require to change health behaviours including diet, exercise, alcohol and compliance with treatment.

[Good practice point] Practitioners using techniques which involve cognitive behaviour therapy or motivational interviewing should receive appropriate training.

[Good practice point] Patients who are resistant to change or who present with more complex problems should be considered for referral to a clinical psychologist or therapist with a similar level of expertise.

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