Stroke: Categorising People Into Low, Moderate Or High Risk Should Be ‘abandoned’
Professor of Epidemiology and Neurology at Auckland University of Technology (AUT), Valery Feigin, says clinicians often seek thresholds to trigger public health interventions. However, this concept is at odds with the fact that risk is a continuum, something that changes gradually without any clear dividing points.
The primary prevention of stroke and cardiovascular disease (which share the same CVD risk assessment) has been dominated by ‘high-risk’ strategies that seek to identify those individuals most at risk and offer targeted interventions.
“The problem with high-risk strategies is they virtually exclude people with low or moderate CVD risk who ultimately make up 80 percent of all strokes and heart attacks. These groups are not prioritised for public health education or interventions,” says Professor Feigin.
“Labelling people as low-risk may also give them false reassurance that they are protected from a stroke or heart attack, compromising their motivation to control any risk factors. This is particularly so for younger people.”
Professor Feigin, Director of the National Institute for Stroke and Applied Neurosciences at AUT, is considered one of the world’s most influential scientific minds – ranking among the top one percent by citations, for his global research on the epidemiology, management and prevention of stroke and traumatic brain injury.
In this month’s Journal of the American Heart Association, he outlines future directions for the primary prevention of stroke and cardiovascular disease.
Professor Feigin recommends an integrated approach to primary prevention that targets major noncommunicable diseases – not just stroke and cardiovascular disease, but also pulmonary diseases, dementia, diabetes and cancer.
This is because nearly everyone is at lifetime risk of developing these diseases, which were prioritised by the World Health Organisation in the global action plan for the prevention and control of noncommunicable diseases.
“Policymakers should prioritise population-wide strategies for the primary prevention of stroke, cardiovascular disease and other major noncommunicable diseases. Focusing on the high risk group is only addressing the tip of the iceberg,” he says.
There is no randomised controlled trial to support the effectiveness of ‘high-risk’ strategies for reducing the incidence or mortality of stroke and cardiovascular disease.
Professor Feigin also advocates a three-tiered plan, combining ‘population-wide’ and ‘high-risk’ strategies with emerging ‘motivational population-wide’ strategies.
Population-wide measures, aimed at minimising exposure to risk factors, would include smoking and alcohol cessation campaigns as well as a move to reduce the amount of salt and sugar in processed foods. While, high-risk CVD screening would identify individuals in need of prophylactic drug therapy, to be delivered in conjunction with lifestyle and behavioural interventions.
Motivational population-wide measures, designed to educate people about behavioural risk factors (poor diet, physical inactivity, smoking and alcohol consumption) and ways to modify them, would include the Stroke Riskometer mobile app endorsed by the World Stroke Organisation and World Heart Federation.
The free mobile app assesses an individual’s risk of stroke within five years and 10 years. Rather than categorising people into low, moderate or high risk, it provides the user with a risk percentage as well as their relative risk (compared to someone of the same age and sex without any contributing risk factors).
Professor Feigin says, it is also time to reassess the way that we evaluate the effectiveness of primary prevention strategies.
“Limiting the criteria for evaluation to frequency estimates is misleading. It does not provide any information about the real-life impact of diseases on the healthcare system and society. The absolute number of people is far more important for healthcare planning and resource allocation than their rates,” he says.
The frequency estimates for stroke and cardiovascular disease have been declining over the past 30 years in almost every country in the world, but the absolute number of people who develop, die from or remain disabled from these disorders has increased dramatically. This is largely due to population growth and ageing, as well as unfavourable trends in the prevalence of some risk factors.