This is a plain English summary of an original research article
A package of extra support, including motivational interviewing, did not add value in terms of boosting weight loss or physical activity in people at high risk of cardiovascular disease, a new study has found.
This NIHR-funded trial recruited 1,220 people deemed at high risk of heart disease or stroke. Researchers compared the clinical and cost-effectiveness of the enhanced support, which was based on cognitive theory, in either a group or individual format. A third group was referred to community-based weight loss, smoking cessation and/or exercise programmes according to usual practice.
Behavioural change interventions can be effective in some circumstances, but the results from this trial underline the importance of designing the right intervention for the right group of patients. Despite their risk, some participants may not have had poor diet or activity levels, limiting the scope of this study to show an effect from the intervention.
Why was this study needed?
In the UK, circulatory disease is still one of the leading causes of death for both men and women. In England, healthcare costs relating to heart disease and stroke are estimated at £7.4 billion per year. While medical advances have resulted in more people surviving heart attacks, there has been a rise in obesity and a decline in physical activity that have put more people at risk.
‘Motivational interviewing’ is a psychological technique that draws on cognitive behavioural therapy and prepares people to initiate and maintain changes. Adopting a healthier lifestyle, including being physically active and maintaining a healthy weight, can significantly reduce the risk of heart disease. Motivational interviewing can be enhanced by other types of support, promoting, for example, setting goals, self-monitoring and social support.
A small number of studies have looked at the effectiveness of motivational interviewing in changing the behaviours that lead to heart disease and stroke – but results have been mixed.
What did this study do?
This randomised controlled trial was carried out in primary care centres in London over 24 months. Participants, whose average age at enrolment was 70, had a 20% or more likelihood of having a cardiovascular event such as a heart attack or stroke in the next 10 years, estimated using the QRISK2 tool.
In group one, 697 people received 10 sessions of training, including goal-setting, role-playing and education, in a group format. The 523 people in group two received the same sessions in individual format.
A third group of 522 people received ‘usual care’ – referrals to community-based weight loss, smoking cessation and/or exercise programmes.
Only 54% of those in the intervention groups completed the course. The sample may have been skewed to non-modifiable risk factors including increasing age and most participants being male, rather than modifiable lifestyle factors such as weight, blood pressure, diet and smoking.
What did it find?
- At 24 months, the group and individual interventions were not more effective than usual care in increasing physical activity (mean difference [MD] 70 steps, 95% confidence interval [CI] -288 to 148 for group sessions; and MD 7 steps, 95% CI -224 to 239 for individual sessions).
- The group and individual arms had slight but significant reductions in weight at 12 months compared with usual care, but there were no differences at 24 months (MD -0.03kg, 95% CI -0.49 to 0.44 for group sessions; and MD -0.42kg, 95% CI -0.93 to 0.09).
- The group and individual interventions were not cost-effective. ‘Usual care’ was thought to be the most cost-effective, and the group intervention the least cost-effective.
What does current guidance say on this issue?
The NICE 2016 guideline on reducing cardiovascular risk (CG181) recommends that those at risk should be identified and given advice on diet and physical activity. This should include emphasising the Government’s guidelines on physical activity targets and providing written information. It advises that GPs should recognise people who need support to change their lifestyles and should refer them to behaviour change and exercise programmes that use techniques such as goal-setting and social support.
In its Public Health Guideline of 2014 (PH49), NICE provides detailed guidance on commissioning behavioural change interventions that have been ‘shown to be effective’.
What are the implications?
These results, put together with others on psychological intervention, show a complex picture with many variables both in terms of risk factors and how an intervention is delivered.
The challenge now is to design studies that allow us to identify the specific elements that may help promote behavioural change in at-risk groups.
Citation and Funding
Ismail K, Bayley A, Twist K et al. Reducing weight and increasing physical activity in people at high risk of cardiovascular disease: a randomised controlled trial comparing the effectiveness of enhanced motivational interviewing intervention with usual care. Heart; 2019;106:447–54.
This project was funded by the NIHR Health Technology Assessment Programme (project number 10/62/03).
NHS website. Cardiovascular disease. London: Department of Health and Social Care; updated 2018.
NICE. Cardiovascular disease: risk assessment and reduction, including lipid modification. CG181. London: National Institute for Health and Care Excellence; updated September 2016.
NICE. Behaviour change: individual approaches. PH49. London: National Institute for Health and Care Excellence; 2014.
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