Dr Alan Begg summarises new SIGN guidance and explains why lifestyle change is an essential aspect of cardiovascular risk reduction
Read this article to learn more about:
- determining a patient’s risk of cardiovascular disease
- essential advice that should be offered to people who are at risk of a cardiovascular event
- pharmacological therapies recommended by SIGN and prescribing thresholds.
In June 2017, the Scottish Intercollegiate Guidelines Network (SIGN) published SIGN 149 on Risk estimation and the prevention of cardiovascular disease,1 followed by SIGN 150 on Cardiac rehabilitation2 in July 2017. This article will focus on SIGN 149 and will discuss risk estimation and primary prevention of cardiovascular disease (CVD). A second article (due to appear in the November 2017 issue of Guidelines in Practice) will cover SIGN 150, and discuss secondary prevention of CVD. There will, however, be some degree of overlap between the articles, as some recommendations apply equally to both situations.
It is important to consider CVD as a continuum from the preclinical to the end-stage disease. Different opportunities to intervene will present at different stages depending on whether the individual in question is at a high or low risk of experiencing a cardiovascular event.1 Considering an individual’s risk of a cardiovascular event throughout the course of the disease should mean that there is no arbitrary differentiation between people presenting before or after a specific event in terms of primary or secondary prevention.1
Since 2007 the ASSIGN score has been used in Scotland to identify individuals at the highest risk of CVD. The ASSIGN score is tailored to the Scottish population by inclusion of social deprivation, family history of premature CVD, as well as additional CVD risk modifiers.3
The decision to commence treatment is based on the probability of an individual experiencing a cardiovascular event over a given period.1
The current Scottish treatment threshold of 20% or greater risk of a cardiovascular event over the next 10 years remains unchanged.1 High-risk individuals in Scotland are defined as: ‘asymptomatic individuals without established CVD (or other conditions which confer automatically high cardiovascular risk), who are estimated to be at 20% or greater risk of a cardiovascular event over the next 10 years’.1 This contrasts with NICE Clinical Guideline (CG) 181 on Cardiovascular disease: risk assessment and reduction, including lipid modification,4 published in July 2014, which recommends a treatment threshold of 10% or greater 10-year risk of developing CVD (estimated using the QRISK2 assessment tool).4
Assessing and determining risk
Many of the risk assessment strategies outlined in the Joint British Societies’ consensus recommendations for the prevention of cardiovascular disease (JBS3)5 are adopted by SIGN 149. The following individuals should be offered an assessment of cardiovascular risk every 5 years:1
- all adults aged 40 years or above
- individuals at any age with a first-degree relative who has premature atherosclerotic CVD or familial dyslipidaemia.
There are certain groups of people who are assumed to be at high risk of CVD and do not require a risk assessment with a scoring system (see Box 1).
Box 1: High-risk groups who do not require risk assessment
Individuals with any of the following risk factors should be considered at high risk of a cardiovascular event:1
- established cardiovascular disease*
- stage 3 or higher chronic kidney disease or micro- or macroalbuminuria
- familial hypercholesterolaemia
- aged ≥40 years with diabetes
- aged <40 years with diabetes and any of the following:
- at least 20 years duration of diabetes
- target organ damage (e.g. proteinuria, micro- or macroalbuminuria, proliferative retinopathy or autonomic neuropathy)
- significant other risk factors in the view of the healthcare professional.
*includes previous myocardial infarction, acute coronary syndrome, revascularisation, stroke, transient ischaemic attack, aortic aneurism, peripheral arterial disease, or those with significant plaque on coronary angiography or carotid ultrasound.
People who are identified as being at high risk should be supported to make lifestyle changes and be offered drug therapy such as statin therapy or blood pressure-lowering medication to reduce their absolute risk.1 SIGN 149 recommends practitioners consider:1
- setting up an annual review to discuss lifestyle modification, medicines adherence, and address CVD risk factors (the frequency of review should be adapted as necessary to the individual)
- other risk factors not included in the CVD risk prediction when assessing and managing the patient’s overall CVD risk; these include:
- body mass index
- atrial fibrillation
- psychological wellbeing
- physical inactivity.
Reducing modifiable risk factors via lifestyle change without the use of pharmacological therapies figures prominently in the SIGN 149 guideline.
Diet is one of the important environmental factors in the development of coronary heart disease (CHD).1
Practitioners should recommend to everyone that a diet low in saturated fats helps to reduce CVD risk; saturated fat intake of no more than 30 g per day for men and 20 g per day for women is ideal. Fish consumption may help to reduce the intake of (saturated) fat from meat, and may have a role in reducing fatal CHD with low risk of adverse effects. Advise people to aim for two 140 g portions of fish per week, one of which should be oily fish. Omega-3 fatty acid supplements should not be offered for the reduction of CVD risk.1
People with hypertension should be advised to reduce their salt intake as much as possible to lower blood pressure, and all individuals should aim to consume less than 6 g of salt per day.1
There is evidence of a 15% reduction in the relative risk of CVD in people who consume high levels of fruit and vegetables compared with people consuming low levels.6 Increased fruit and vegetable consumption is recommended for the entire population to reduce cardiovascular risk.1
Do not offer antioxidant vitamin supplementation for the prevention or treatment of CHD, and do not offer homocysteine-lowering interventions (folate or B-vitamin supplementation) for the prevention or treatment of cardiovascular disease.1
Advise adults who are at high risk of CVD or with established CVD to adopt a Mediterranean diet pattern supplemented with 30 g extra virgin olive oil or unsalted nuts per day. Use the Eatwell Guide (the UK Government’s advice on healthy eating) to help individuals make informed choices around the selection of dietary components and their optimal proportions; this conforms to Mediterranean diet patterns and supports restriction of saturated fat, sugars, and salt intake.1
Stanol esters and plant sterols can reduce low-density lipoprotein (LDL) cholesterol; however, the guideline development group found no evidence to support whether this reduction persists over the long term, and whether this translates to a reduction in CVD events.1
People who are overweight or obese should be targeted with interventions designed to reduce weight by at least 3 kg and to maintain this reduction. It is good practice to measure the patient’s weight annually. This level of weight loss can lead to LDL cholesterol reductions of around 0.2–0.3 mmol/l; however, insufficient data were found to determine the effects of lifestyle-mediated weight loss on morbidity or mortality outcomes.1
The guideline development group for SIGN 149 identified 10 observational studies, which after correcting for other risk factors, confirmed an inverse relationship between physical activity and the risk of a coronary event.1
Physical activity of at least moderate intensity (i.e. to the point where breathing is faster than normal) is recommended for the whole population (unless contraindicated by an individual’s condition). This may include occupational and/or leisure-time activity and should incorporate accumulated bouts of moderate-intensity activities such as brisk walking.
- encourage all people irrespective of health, fitness, or activity level, to increase activity levels gradually
- encourage people who are moderately active to:
- increase their activity level if they are able to do so (activity can be increased through a combination of changes to intensity, duration, or frequency)
- undertake vigorous-intensity exercise to achieve additional benefits (unless contraindicated)
- advise people to minimise the amount of time spent being sedentary over extended periods.
All cardiovascular events, including CHD, stroke, peripheral arterial disease, and cardiovascular death are strongly associated with tobacco smoking; CVD risk is mediated by the number of cigarettes smoked.1
Priority should be given to:1
- identifying and supporting young people to stop smoking
- developing programmes for smokers on low incomes to stop smoking.
All people who smoke should be advised to stop and offered support to help facilitate this, and any exposure to passive smoking should be minimised.
Excessive alcohol consumption is a well-established risk factor for cardiovascular disease. Alcohol can also impact on other long-term conditions such as mental health, liver disease, and cancer, and this should be considered when providing advice in a clinical setting.1
Advise people with or without evidence of CVD to reduce their alcohol consumption and mention that even light to moderate alcohol consumption may increase CVD risk.1
For people with CHD, follow national health promotion advice:1
- men and women should regularly drink no more than 14 units per week to keep health risks from drinking alcohol to a low level
- for people who do consume as much as 14 units per week, it is best to spread this evenly over 3 days or more.
It should be borne in mind that one or two heavy drinking sessions per week will increase the risks of death from long-term illnesses and from accidents and injuries.1
Practitioners should advise patients that the risk of developing a range of illnesses (including cancers of the mouth, throat, and breast) increases with the amount they drink on a regular basis. Suggest to the patient that a good way to cut down the volume of alcohol consumed is to establish several drink-free days each week.1 Use brief multi-contact interventions (see Box 2) to encourage people to reduce their levels of drinking if their current intake is hazardous to their health.
Box 2: brief interventions to reduce alcohol consumption1
- Information and education on:
- adverse effects of alcohol
- recommended levels of alcohol consumption
- risks involved in consumption of alcohol
- strategies for changing drinking habits
- Feedback and advice on prevalence of drinking
- Drinking cues
- Drinking diaries
- Drinking agreement/contract
- Retrospective self report of drinking alcohol or current alcohol quantity, quality, and type
- Discussion of injuries and healthcare utilisation due to alcohol
- Feedback of personal health data.
Interestingly, the guideline does not recommend universal screening as a case-finding exercise in primary care;1 universal screening is used in some areas of the UK as an incentivised approach to identify problem drinkers in primary care.
The choice of products in any smoking cessation regimen should be determined by patient preference and smoking habits.
Varenicline has been reported to reduce lifetime NHS costs for a cohort of smokers as well as generating more Quality Adjusted Life Years (QALYS) compared with other ways of quitting smoking.7
Offer varenicline or combination nicotine replacement therapy (either alone or as part of a smoking cessation programme) alongside professional advice. This can increase long-term abstinence rates. Alternatively, consider either bupropion or single nicotine replacement therapy as smoking cessation treatments.1
The benefits of e-cigarettes for smoking cessation remain unclear, and so SIGN 149 makes no recommendations on their use as an intervention.1 E-cigarettes are being superseded by electronic nicotine delivery systems (ENDS), which may be a more efficient way of delivering nicotine to the body; however, the harms and benefits of ENDS as a smoking cessation intervention are yet to be extensively researched.1
Do not recommend aspirin for primary prevention of CVD, or for people with diabetes or hypertension who do not have a diagnosis of CVD. There is insufficient evidence regarding the use of aspirin in people with chronic kidney disease (CKD) and no established CVD.
Evidence from genetic studies and RCTs show that maintaining lifelong lower LDL cholesterol levels results in a reduction in cardiovascular events, and there is also strong evidence for the benefit of using drug therapy to lower LDL cholesterol and reduce cardiovascular risk.8,9
Statin therapy has been shown to reduce major atherosclerotic cardiovascular events and the need for arterial revascularisation by about 20–25% per 1 mmol/l reduction in LDL cholesterol. In terms of lowering of cardiovascular risk, emphasis should be placed on cholesterol reduction, rather than treatment modality.1
Take a lipid profile of the patient to assess their cardiovascular risk (NB non-fasting samples are initially suitable for screening purposes). This should include total cholesterol, high-density lipoprotein cholesterol, and triglycerides. Lipid profiles should not be taken at the time of intercurrent illness.1
It is best practice to consider and exclude any secondary causes of dyslipidaemia before commencing lipid lowering therapy. After an informed discussion of risks and benefits of treatment, offer atorvastatin 20 mg/day to adults who are assessed as being at high cardiovascular risk, but have no established CVD.1 This treatment is in line with NICE CG181, with the exception of the treatment threshold.4
In people already taking an alternative regimen due to reported intolerance with atorvastatin, there is no need to change their current regimen.1
Patients who report statin intolerance can be rechallenged if they are willing, initially with the same dose of the same statin unless they have significant creatine kinase elevation. If the reported statin intolerance persists, offer the patient an alternative statin. Advise patients who are started on a statin to report unexplained muscle pains or other adverse effects promptly, especially if they are associated with fever or malaise.1
Refer individuals with a possible diagnosis of familial hypercholesterolaemia (FH) to a specialist clinic for investigation and initial management.1
Offer statin therapy to people with FH regardless of their calculated cardiovascular risk and consider combination therapy with ezetimibe where LDL cholesterol-lowering is inadequate on the maximally-tolerated statin therapy, or monotherapy where statins are contraindicated.1
For individuals with heterozygous FH who have elevated LDL cholesterol despite statin monotherapy or statin/ezetimibe combination therapy, consider offering a proprotein convertase subtilisin/kexin type 9 inhibitor.1
Chronic kidney disease
Offer statin therapy to patients with CKD stage 3 and above, or with micro- or macroalbuminuria, who are not on dialysis.1
Ezetimibe and bile acid sequestrant therapy should only be considered for primary prevention of CVD in patients at elevated CVD risk in whom statin therapy is contraindicated, and in patients with FH.1
Reducing blood pressure
Elevated blood pressure (BP) increases the risk of CHD, heart failure, stroke, and renal failure. Using antihypertensive drugs to lower BP is associated with reductions in CHD, stroke, heart failure, and both cardiovascular and total mortality.1
High cardiovascular risk
Offer blood-lowering drug therapy to people with stage 1 hypertension, especially if there is clinical evidence of target organ damage (see Box 3 for definition) such as retinopathy, proteinuria, or left ventricular hypertrophy.
*In JBS3,5 stage 1 hypertension is defined as:
- office BP >140/90 mmHg but <160/100 mmHg
- ambulatory BP monitoring (ABPM) 24-hour average ≥135/85 mmHg
- home ABPM average ≥135/85 mmHg.
Box 3: Target organ damage
The JBS3 guideline defines target organ damage as any of the following:1,5
- heart failure
- established coronary heart disease
- stroke or transient ischaemic attack
- peripheral arterial disease
- abnormal renal function (elevated serum creatinine or proteinuria/microalbuminuria)
- hypertensive or diabetic retinopathy
- left ventricular hypertrophy on electrocardiogram or echocardiogram.
Offer blood pressure-lowering treatment to people with diabetes if their baseline clinic systolic pressure is >140 mmHg. This can help prevent mortality, macrovascular events, and progression of nephropathy and retinopathy.1 Treatment is still worth considering even if the systolic clinic blood pressure is <140 mmHg to reduce the risk of stroke, progression of retinopathy, and albuminuria; at this level of blood pressure, treatment should be targeted at patients thought to be at greatest risk of complications.1
All people with stage 3 or higher chronic kidney disease, or micro- or macroalbuminuria should be offered blood pressure-lowering treatment.1 All patients on dialysis should be offered blood pressure-lowering treatment.1
Blood pressure targets
In SIGN 149, the target figures for blood pressure are provided as a general guide, and may be adapted in the light of medicines tolerance, particularly in people who are frail or elderly people as they may be more susceptible to adverse effects of treatment. In such patients, more modest reductions in blood pressure may still be beneficial.1
SIGN 149 recommends the following BP targets:1
- <140/90 mmHg (clinic measurement) for individuals with uncomplicated hypertension
- <135/85 mmHg (clinic measurement) for individuals with established CVD and diabetes, chronic renal disease, or target organ damage.
Routine lowering of BP below 130/80 mmHg is not recommended as this brings limited additional benefits with risk of significant adverse effects. In any individual with hypertension, consideration should be given to using two or more antihypertensive agents, in half to standard doses, to achieve additive blood pressure lowering while minimising the adverse effect profile.1
Implementing SIGN 149
This is the third SIGN guideline to address risk estimation and prevention of cardiovascular disease in individuals without CVD. The first was published in 199910 and the second in 200711 and with the publication of SIGN 149, implementation remains the responsibility of each NHS board as an essential part of clinical governance. As health systems continue to diverge across the devolved nations it will, with time, become easier to identify any difference in outcomes resulting from differing guidance, treatment thresholds, implementation approaches, and professional activity in preventing cardiovascular disease.
- CVD is a continuum of risk before and after the first event
- The ASSIGN score is tailored to the Scottish population
- The current Scottish 20% risk threshold for intervention is unchanged
- An assessment of risk should be offered every 5 years to:
- all adults aged 40 years or above and
- individuals at any age with a first-degree relative who has premature atherosclerotic CVD or familial dyslipidaemia
- Recommend a diet low in saturated fat
- High consumption levels of fruit and vegetables will reduce CVD relative risk
- All people should be encouraged to increase their physical activity and avoid excessive alcohol consumption
- Combination pharmacotherapy should be offered for smoking cessation
- Antiplatelet agents are not used for primary prevention of CVD
- Cholesterol and blood pressure-lowering therapies should be used where appropriate.
GP commissioning messages
written by Dr David Jenner, GP, Cullompton, Devon
- SIGN 149 makes similar recommendations to NICE CG181 for England and Wales with the exception of:
- use of the ASSIGN score to assess CVD risk (as it is tailored to the Scottish population)
- a threshold of 20% or greater risk of a cardiovascular event over the next 10 years (NB NICE recommends a treatment threshold of 10% or greater 10-year risk of developing CVD)
- Lifestyle interventions should be considered at all stages and even before an increased CVD risk is identified as these interventions will benefit all
- CVD risk assessment is recommended every 5 years for people aged over 40 years (in England this is incentivised through the NHS health check scheme commissioned by local departments of public health)
- may wish to target assessments to individuals likely to be at higher risk and socially excluded groups who do not usually present to health services
- should consider funding specific lifestyle facilitators to support communities and primary care healthcare services to achieve the lifestyle objectives for whole populations
- In England, health and wellbeing boards should promote healthy lifestyles through their health and wellbeing strategies, involving many agencies and promoting exercise.
Read the Guidelines summary of SIGN guideline 149 on Risk estimation and the prevention of cardiovascular disease for more recommendations on managing the risk of cardiovascular disease
- SIGN. Risk estimation and the prevention of cardiovascular disease. SIGN 149, 2017. Available at: www.sign.ac.uk/sign-149-risk-estimation-and-the-prevention-of-cardiovascular-disease.html
- SIGN. Cardiac rehabilitation. SIGN 150, 2017. Available at: www.sign.ac.uk/sign-150-cardiac-rehabilitation.html
- ASSIGN score. Estimate the risk. Available: www.assign-score.com/estimate-the-risk/ (accessed 6 October 2017)
- NICE. Cardiovascular disease: risk assessment and reduction, including lipid modification. Clinical Guideline 181. NICE, 2014. Available at: www.nice.org.uk/guidance/cg181
- JBS3 Board. Joint British Societies’ consensus recommendations for the prevention of cardiovascular disease (JBS3). Heart, 2014; 100: Suppl 2:ii1–ii67. doi: 10.1136/heartjnl-2014-305693.
- Law M, Morris J. By how much does fruit and vegetable consumption reduce the risk of ischaemic heart disease? Eur J Clin Nutr 1998; 52 (8): 549–556.
- Scottish Medicines Consortium. Varenicline 1mg tablets (Champix®). SMC, 2006. Available at: www.scottishmedicines.org.uk/files/varenicline_Champix_339_06.pdf
- Cholesterol Treatment Trialists’ (CTT) Collaboration, Baigent C, Blackwell L et al. Efficacy and safety of more intensive lowering of LDL cholesterol: a meta-analysis of data from 170,000 participants in 26 randomised trials. Lancet 2010; 376 (9753): 1670–1681.
- Ference B, Yoo W, Alesh I et al. Effect of long-term exposure to lower low-density lipoprotein cholesterol beginning early in life on the risk of coronary heart disease: a Mendelian randomization analysis. J Am Coll Cardiol 2012; 60 (25): 2631–2639.
- SIGN. Lipids and the primary prevention of coronary heart disease. SIGN 40, 1999.
- SIGN. Risk estimation and the prevention of cardiovascular disease. SIGN 97, 2007.