There are three considerations about cardiac risk calculators. The first is that, whichever exact approach is taken, the idea is the same - to take measurements of cardiovascular health and analyze them for guidance on future potential heart problems and their prevention.
The second is that while the factors are common to whichever calculator is used, it is often one recommended by a doctor, validated for as much scientific accuracy as possible.
The third is that a prediction of future chances of heart problems is just that - a prediction. It is not supposed to be as scary or as certain as it might sound.
Risks can be put into perspective, and they would not be calculated unless there was something worthwhile that could be done to reduce them.
For some people, the predicted cardiac risk is so low that there would be no need to worry about further screening.
The reason why medicine has developed cardiovascular risk calculators is for the major effort to take on "the common risk factors fueling the epidemic of cardiovascular disease" - work that was pioneered by the game-changing Framingham Heart Study.1,2
Here are some key points about cardiovascular risk calculation. More detail is found in the article.
- Population statistics have worked out the most important risk factors for cardiovascular disease
- With this information, doctors have access to powerful predictors of individual heart attack risk based on factors that can lead to blocked arteries
- Reducing the risk of heart attacks and stroke for people as they get older can be helped by measuring individual biological factors, including those with direct or indirect links to lifestyle
- Age is one risk factor that cannot be modified but others such as cholesterol and blood pressure can
- The idea of these early predictions for a raised risk of a major heart event within 10 years is a guide for lifestyle changes that can bring the predicted risk down toward normal percentage chances
- People at a high risk of heart problems may require medical help such as statins or blood pressure drugs
- 10-year cardiac risk calculators are not designed for people who already have clinical cardiovascular disease - although there is still an element of risk predictability for these people, and doctors can still help with management and treatment.
What is a cardiac risk calculator?
Heart and brain can be affected by the balance of individual cardiovascular risks.
A cardiac risk calculator takes data for an individual's predictors of disease and uses population-level statistics to try and predict their chances of cardiovascular problems. These calculators return a percentage score to indicate heart risk.
Tools for working out how much more likely a heart attack might be over time are not for everyone. Such information is not useful for people who have been diagnosed with cardiovascular disease as their risks are already actively managed in a treatment direction rather than in this preventive direction.
This article will examine what factors are used by cardiac risk calculators and why, and what lifestyle measures and medical assistance can do to affect them.
Medical professional societies and charitable organizations in the UK published heart disease prevention recommendations in the journal Heart in March 2014, when they also launched the JBS3 risk calculator.
The leading doctor behind this story used a presentation at the American Heart Association (AHA) meeting in November 2015 to call for all women over 40 to get their A-risk score, also known as the atherosclerotic cardiovascular disease (ASCVD) score.
What factors do cardiac risk calculators use?
All cardiac risk calculators use biological factors proven through large-scale studies to be related to the statistical chances of developing diseased arteries.
Some of these indicators are possible to be treated; these are known as modifiable risk factors. As a result, some of the causes of atherosclerosis and heart disease can be avoided or reduced.
Heart attack and stroke from clogged arteries are more likely with high cholesterol and high blood pressure among other factors.
Atherosclerosis is the narrowing of arteries due to the formation of plaques, which can happen in the arteries supplying the heart - the coronary arteries.
Heart disease prevention also helps against other problems as atherosclerosis can lead to stroke events when blood supply is cut off in part of the brain.
When cardiac risk is measured, three key factors cannot be adjusted: age, ethnicity and biological sex. Other factors are modifiable.
The best way to see all the elements used in a cardiac risk calculator is simply to have a look at one key example, jointly developed by the American College of Cardiology (ACC) and the American Heart Association (AHA).
Doctors may follow these 2013 risk assessment guidelines for anyone over 20 years of age and no older than 79 who is yet to show any outward signs of cardiovascular disease.3
The ACC/AHA risk score draws from a number of factors, and a calculator tool returns the result when clinical data from the following sources are put in:
- Patient characteristics and answers
- Doctor's office measurements
- Laboratory test results.
The predictor takes all the following variables recorded by those three sources to work out an individual risk score:
- Biological sex
- Total cholesterol and HDL cholesterol levels
- Blood pressure
- Treatment for high blood pressure (hypertension)
- Diabetes status
- Smoking status.
The score suggests the percentage chance of a heart attack or stroke within an individual's lifetime and within the next 10 years.
Conducting such a risk assessment requires accurate data from clinical testing and careful interpretation. Doctors will consider the individual meaning of doing a risk calculation and looking at the results.
How often the assessment is recommended depends on the age of the patient, with older groups being assessed up to as often as every 4 years.
The results give an indication of whether lifestyle adjustments or other preventive steps are needed to reduce cardiovascular risk.
Physicians should use slightly different risk calculations when needed - some ethnic and genetic characteristics are linked to a slightly higher risk when compared with the overall population, for example, while other people can have a lower risk according to nationwide statistics.
In the US, for example, if a cardiac risk calculator does not take account of these variables, it could slightly overestimate the risk in Puerto Rican people or underestimate it in Mexican Americans.
Best cardiac risk calculators
All cardiac risk calculators do a similar job. The best cardiac risk calculator chosen by a doctor or health care provider would simply be the one selected for its relevance to the patient population and then to fit the individual patient's overall state of health.
In the US, for example, doctors might base heart prediction scores and prevention recommendations on guidance from experts across the ACC, AHA and American Stroke Association.
Another calculator is provided by the US National Heart, Lung, and Blood Institute, which while presented to patients also requires having the readings for cholesterol and blood pressure. The relatively small role of ethnicity as a population and genetic statistic is not used for this tool.
Doctors in the UK might opt to use the calculator provided by the Joint British Societies (JBS) for the prevention of cardiovascular disease.1
Their risk calculation tool is based on wide cardiovascular consensus published in the journal Heart.
This calculator considers the impact of socioeconomic status in raising the risk of disease; users can select one of the following three broad indicators:
- Least affluent
What cardiac risk statistics can show
The JBS calculator can give doctors the option of showing:
- The result as "heart age"
- A thermometer image of expected "healthy years" of no cardiovascular disease
- An "outlook screen" that indicates the likely future need for medical intervention.
Heart prevention charts are like early warning systems, to avert future acute heart problems in the hospital.
The European Society of Cardiology (ESC) offers a CVD prevention toolbox.4
As well as giving an individual calculator tool, visual cues to the meaning of the results can be seen in grids provided for health care professionals and researchers helping to manage population cardiovascular risks.
The ESC - one of many organizations behind recommendations in the European Heart Journal - has risk charts that use colors running from left to right to indicate cardiovascular risk - from green, through yellow and orange, to red:
- Both charts are based on geographic region, gender, age, blood pressure, cholesterol and smoking
- One is for groups at a high risk of a serious heart attack within 10 years - showing more to the red side and less to the green
- The second chart is for lower-risk groups, revealing much more green across the tables.
The colors in these charts reveal the following (for 10-year risk against ESC heart variables):
- A light green result indicates a 1% chance of fatal heart attack (dark green indicates a risk of less than 1%) - for example, healthy people in their 40s or early 50s, women especially, who do not smoke
- Yellow indicates a 2% risk - for example, people into their 50s with raised blood pressure (BP) and cholesterol
- Orange indicates a 3-4% risk - an example would be a 55- to 60-year-old woman in a high range of BP or blood fats if a smoker - although for a man, such an orange risk picture is more likely even with no smoking
- Smoking strongly draws anyone's risk over to the red area on the charts
- There are deeper shades of red indicated at three brackets - 5-9%, 10-14%, and 15% or more - for people, irrespective of smoking, who are older and have high cholesterol and blood pressure.
As for any cardiac risk indication, population statistics such as these can only give an indication of individual chances. Such population heart charts do not take account of everything - for example, a person can be under the care of a doctor for diabetes, which would affect their cardiovascular risk.
There are always important individual factors that can be taken into account, and charts are aimed at helping health care professionals to know when more help may be needed.
What can I do about my cardiac risk calculation?
While patients can try to reduce the risks to the heart and brain, it is not always easy to do this. Not all cardiovascular disease (CVD) risk factors are controllable.
Health care professionals and doctors, including specialists such as cardiologists, can decide where CVD preventive efforts need to be focused, what factors are most within their control and what other options might be available to patients over time.
When a health care professional discusses a cardiac risk calculator score with their patient, they may discuss:
- The treatment measures patients can take themselves, such as tackling cholesterol levels, being physically more active, and so on
- Any tests, advice and medical interventions that may become appropriate.
Not taking up smoking, or committing to smoking cessation, is a key lifestyle measure that can reduce cardiac risk.
Managing cholesterol and lifestyle5
One of the main factors that can increase the cardiac risk percentage is the level of cholesterol in the blood. This can be obtained from a blood test for total cholesterol, or from the two types of cholesterol-carrying lipoprotein:
- Low-density lipoprotein (LDL) has become known as "bad" cholesterol, and within the overall cholesterol equation, high-density lipoprotein (HDL) is known as "good" cholesterol
- It is considered best to have more good cholesterol than bad, and not too much cholesterol overall
Learn more about what cholesterol is, including information on the range of foods that form part of a heart-healthy diet that is recommended for high cholesterol levels.
What is blood pressure? How is it measured and what is normal?
Diet and exercise are just two factors in the treatment of high cholesterol, and it is limiting the consumption of certain fats in the diet that helps to manage cholesterol levels. Learn more about high cholesterol levels.
Specifically, reduce fat intake by limiting the amounts of:
- Cholesterol from animal foods, such as egg yolks, meat and cheese
- Saturated fats from some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods
- Trans fats found in some fried and processed foods.
People who already have cardiovascular disease, or who have a higher risk due to other conditions - for example, diabetes - might be offered cholesterol-lowering drug therapy such as statins.
Such medication may also be needed for people who have not succeeded, or have been unable to succeed, at reducing their cholesterol levels with lifestyle measures alone.
Managing blood pressure
Again, lifestyle measures also help if one of the factors affecting cardiac risk is raised blood pressure. Exercising more and reducing salt intake are particularly effective.
Medications can become necessary to help control high blood pressure (hypertension).
Doctors have long known that stopping smoking - or not starting smoking and becoming addicted - is a big factor in preventing heart disease in addition to tackling other disease risks.
Learn more about how to quit smoking with our relevant Knowledge Center article.