Primary prevention of cardiovascular disease (CVD) involves prevention in patient groups without existing disease (as opposed to secondary prevention for patients with known CVD, all of whom should be considered for risk reduction therapy). Ischaemic heart disease (IHD) causes 30% of male and 22% of female deaths in England (higher in Scotland). The focus of prevention in recent guidelines has switched from IHD to cardiovascular disease to emphasise the need for stroke prevention.

Primary care is ideally placed to pursue primary prevention, and this should be done both systematically in patients at increased risk (e.g. hypertensives, diabetics, familial hyperlipidaemia or a strong family history of CVD¹), and opportunistically whenever a clinician becomes aware of any new risk factors. The Joint British Societies' (JBS 2) guidelines recommend that all adults from age 40 years onwards should be considered for an opportunistic comprehensive CVD risk assessment in primary care.¹ Ideally this should be repeated every 5 years whilst the patient is below treatment thresholds.

Cardiovascular risk estimation

Whenever risk factors are identified they should not be considered in isolation, but the 10-year CVD risk should be calculated and used as the basis for recommendations to reduce the risk. Risk assessment should include ethnicity, smoking habit history, family history of CVD and measurements of weight, waist circumference, blood pressure, lipids (total cholesterol and high-density lipoprotein (HDL) cholesterol) and glucose. The American Heart Association (AHA) guidelines also recommend recording the pulse rate and rhythm to screen for atrial fibrillation.²

Once all risk factors have been identified, cardiovascular risk charts or calculator should be used to estimate the total risk of developing CVD over the following 10 years. A total CVD risk of over 20% over 10 years is defined as high-risk. People with moderate-to-high risk are more likely to be compliant with lifestyle changes and preventative medication if given information about their individual cardiovascular risk.^3,4

• The National Institute for Health and Clinical Excellence (NICE) recommends that the modified Framingham 1991 10-year risk equations (as used in the JBS 2 risk calculator) should be used to assess CVD risk.⁵ CVD risk includes risk of fatal and nonfatal stroke (including transient ischaemic attack), and coronary heart disease (myocardial infarction and angina).⁵ The JBS 2 tool is based on the following risk factors: age, sex, smoking habit, systolic blood pressure, left ventricular hypertrophy, and the ratio of total cholesterol to HDL cholesterol. Recent versions can adjust risk on the basis of central obesity, South Asian ethnic origin, and impaired fasting glucose. For the CVD calculator see separate article Primary Cardiovascular Risk Calculator.
• The JBS 2 risk calculator is not the only risk calculator in use and tends to be less accurate for certain population groups, e.g. women, ethnic minority groups, social deprivation. The QRISK®2 calculator adjusts for some of these factors (e.g. deprivation - using postcode), and is gaining increased acceptance in the UK (as it uses UK rather than Framingham (USA) data); see separate article QRISK2 Cardiovascular Risk Score.
• Over the age of 70 years CVD risk is usually greater than 20% over 10 years, especially for men, but total CVD risk should still be formally estimated using the charts. However, this will underestimate the true total CVD risk of a person older than 70 years.
• Formal risk assessment is not necessary for people with established atherosclerotic CVD, hypertension with target organ damage, familial dyslipidaemias such as familial hypercholesterolaemia, or diabetes. All these groups are at high total CVD risk and should be managed as for secondary prevention.

It is becoming recognised that the pulse pressure (PP) is a better independent risk factor in the elderly and represents an age-related shift in the risk component of blood pressure from diastolic to systolic to pulse pressure. It is possible that future risk prediction tables and calculators might reflect this change.⁶

Interventions^1,2

Reduction of risk of developing CVD involves lifestyle modifications, drug treatment and effective management of any overt underlying medical condition, e.g. diabetes, hypertension, hyperlipidaemia.

Lifestyle factors⁵

• Advise people to eat a diet in which:
  • Total fat intake is 30% or less of total energy intake.
  • Saturated fats are 10% or less of total energy intake.
  • Dietary cholesterol is less than 300 mg/day.
  • Saturated fats are replaced by monounsaturated and polyunsaturated fats.
• Advise eating at least:
  • Five portions of fruit and vegetables per day.
  • Two portions of fish per week, including a portion of oily fish.
  • Advise pregnant women to limit their intake of oily fish to two portions a week.
  • Do not routinely recommend omega-3 fatty acid supplements or plant sterols and stanols for primary prevention.
• Physical activity:
  • Advise people to take 30 minutes of at least moderate-intensity exercise a day, at least 5 days a week.
  • Encourage people who cannot manage this to exercise at their maximum safe capacity.
  • Recommend exercise that can be incorporated into everyday life, such as brisk walking, using stairs and cycling.
  • Tell people that they can exercise in bouts of 10 minutes or more throughout the day.
  • Take into account the person's needs, preferences and circumstances.
  • Agree goals and provide written information about the benefits of activity and local opportunities to be active.
• Weight management:
  • Offer people who are overweight or obese advice and support to work towards achieving and maintaining a healthy weight.
• Alcohol consumption:
  • Advise men to limit their alcohol intake to 3-4 units a day.
  • Advise women to limit their alcohol intake to 2-3 units a day.
  • Advise everyone to avoid binge drinking.
• Smoking cessation:
  • Advise all people who smoke to stop.
  • If people want to stop:
  • Provide structured advice and support, with use of medication to help smoking cessation when appropriate.

Drug treatment

• Hypertension: screen for hypertension and treat appropriately according to British Hypertension Society (BHS) guidelines.⁷
• Aspirin: although use of aspirin is widely accepted for secondary prevention, results in primary prevention are inconclusive. Recent studies have found that aspirin doubles the risk of gastrointestinal bleeding and current opinion is that this outweighs any benefits which might be conferred in reducing the onset of CVD.
• Lipid-lowering drugs:⁸ Statin treatment as part of primary prevention for adults with a 10-year risk of 20%. Usual treatment should be with simvastatin 40 mg. Higher-dose statins should not be used as there are no randomised controlled trials comparing high and low intensity statins in relation to cardiovascular outcomes in people without CVD.
  • Do not set a target concentration for total cholesterol or low-density lipoprotein (LDL) cholesterol in primary prevention.
  • Once a patient has started taking a statin, repeat lipid measurement is unnecessary. Clinical judgment and the patient's preference should guide the review of drug treatment and whether to review the lipid profile.

Document references

1. No authors listed, JBS 2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart. 2005 Dec;91 Suppl 5:v1-52.
2. American Heart Association; Primary Prevention Cardiovascular Disease in Adults
3. Sheridan SL, Viera AJ, Krantz MJ, et al; The effect of giving global coronary risk information to adults: a systematic Arch Intern Med. 2010 Feb 8;170(3):230-9. [abstract]
4. Casebeer L, Huber C, Bennett N, et al; Improving the physician-patient cardiovascular risk dialogue to improve statin adherence; BMC Fam Pract. 2009 Jun 30;10:48. [abstract]
5. Lipid modification, NICE Clinical Guideline (May 2008); (Cardiovascular risk assessment and the modification of blood lipids for the primary and secondary prevention of cardiovascular disease.)
6. Assmann G, Cullen P, Evers T, et al; Importance of arterial pulse pressure as a predictor of coronary heart disease risk in PROCAM. Eur Heart J. 2005 Oct;26(20):2120-6. Epub 2005 Sep 1. [abstract]
7. Williams B, Poulter NR, Brown MJ, et al; British Hypertension Society guidelines for hypertension management 2004 (BHS-IV): summary. BMJ. 2004 Mar 13;328(7440):634-40.
8. Cooper A, O'Flynn N; Risk assessment and lipid modification for primary and secondary prevention of cardiovascular disease: summary of NICE guidance. BMJ. 2008 May 31;336(7655):1246-8.

Internet and further reading

• Food Standards Agency; Eat well, be well
• NHS; 5 (fruit and vegetables) a day

Acknowledgements