This calculator uses the Framingham risk equation¹ and the adjustments as suggested by the Joint British Societies' (JBS2) paper² and the JBS Cardiovascular Risk Assessor.³

The latest National Institute for Health and Clinical Excellence (NICE) Guidance (2010) does not recommend any particular risk calculator, but does emphasise that any which are based on the Framingham risk equation may overestimate risk in UK populations.⁴ An alternative is the Qrisk®2 calculator here.

Notes

• Impaired fasting glucose (IFG) = fasting glucose ≥6.1 mmol/L and <7.0 mmol/L.
• Risk thresholds for drug treatment will vary according to circumstances. In the UK, statin therapy is recommended as part of the management strategy for the primary prevention of CVD for adults who have a 20% or greater 10-year risk of developing CVD.⁴
• In the original Anderson paper,¹ based on the Framingham Heart Study, the CVD group (option **CVD in the calculator above) was a very mixed bag of conditions, consisting of MI and CHD death (plus angina pectoris and coronary insufficiency), stroke (including transient ischaemia) plus congestive heart failure and peripheral vascular disease. This is not a good match to the CVD end-point in statin and hypertension trials and should not be used.⁵ The JBS calculator² calculates CVD risk as the sum of CHD risk and stroke risk (JBS Risk option in the calculator above) as this is in better agreement with the original New Zealand CVD risk charts;⁵ so this calculator may be used as an alternative to the new paper CVD Risk charts.⁶ The other (non-JBS) risk calculation results are as per the original Anderson paper,¹ but all results will be adjusted by risk multipliers as described below (family history, central obesity, etc.) if selected.
• The following patients should not have their risk calculated, as they are considered already to be at high enough risk to justify lifestyle and other interventions (antithrombotic, antihypertensive and lipid-lowering therapies).²
  • Patients with atherosclerotic CVD.
  • Hypertension (≥160/100 mm Hg) with target organ damage.
  • Patients with type 1 or type 2 diabetes mellitus.
  • Renal dysfunction (including diabetic nephropathy).
  • Familial hypercholesterolaemia, familial combined hyperlipidaemia or other inherited dyslipidaemia as identified by Simon Broome diagnostic criteria.⁷
  • People aged 75 or older should also be considered at increased risk of CVD, particularly if hypertensive or smokers. They are likely to benefit from statin treatment. Assessment and treatment should be guided by the benefits and risks of treatment, informed preference and comorbidities that may make treatment inappropriate.⁴
  • The JBS2 guidelines also include TC to HDL-C ratio ≥6² but this was not included in the NICE guidance.
• The following patients have higher risks:
  • Significant family history (Men <55 and women <65 years with one first-degree relative) increases risk by a factor of 1.5, as does impaired fasting glucose and South Asian origin.⁸ If more than one first-degree relative is affected, the risk may be increased by a factor of up to 2.⁴ Identification of familial hyperlipidaemia is described in the NICE guidance.⁷
  • Obesity (BMI ≥30 kg/m²), especially central obesity in men with waists ≥102 cm in Caucasians, (≥90 cm in Asians). Corresponding waist values for women are ≥88 cm and ≥80 cm. Obesity increases risk by a factor of 1.3.
  • Serum triglyceride of 1.7 mmol/L or more increases CVD risk by 1.3 times (this calculator treats it the same as obesity). A low HDL cholesterol (<1.0 mmol/L in men and <1.2 mmol/L in women) also increases risk.
  • If any combination of impaired fasting glucose, South Asian origin, adverse family history or raised serum triglyceride occurs, risk is only increased by whichever of these factors in the combination gives the highest risk. In this calculator, none of them increases the risk further when left ventricular hypertrophy (LVH) is present - as LVH increases risk so much that further multiplying risk to take into account other factors is likely to be inaccurate.⁵
    
    Also although, for example, it can be shown that raised serum triglyceride increases risk by about 1.3 times, including triglyceride in a multivariate equation will reduce the variation in risk explained by the other risk factors. Successively multiplying risk for factors not included in the original equations of Anderson and colleagues will thus lead to gross overestimations of risk. On the other hand, the clinician should be aware in making clinical decisions that combinations of risk factors such as family history, high triglyceride, South Asian origin, and impaired fasting glucose are likely to increase risk above that shown by the programme.
• There are no targets for total cholesterol reduction in the primary prevention of CVD. Aim to start a patient on 40 mg of simvastatin or equivalent.
• Use pre-treatment values where available - using or substituting values on treatment are only a guide to risk trends and probably underestimate actual risk. If pre-treatment values are not available, JBS 2 suggests using BP of 160/90 mm Hg, and a total cholesterol/HDL ratio of at least 6.²
• LVH = definite LVH on ECG.
• Patients should be considered as a smoker = if they currently smoke or are in the first few years of stopping. Actual increased risk of ex-smokers will depend on lifetime exposure to cigarettes, and will lie between the never smoked and still smoking values.

Document references

1. Anderson KM, Odell PM, Wilson PW, et al; Cardiovascular disease risk profiles. Am Heart J. 1991 Jan;121(1 Pt 2):293-8. [abstract]
2. 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.
3. The Joint British Societies Cardiovascular Risk Assessor (V01.06), Heart Uk Website
4. 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.) amended May 2010
5. Information kindly provided by Professor Paul Durrington, Department of Medicine, University of Manchester, Manchester Royal Infirmary, Oxford Road, Manchester. M13 9WL and Dr Maggie Ireland, SpR in Public Health MedicineNorthumberland Care Trust.
6. New JBS2 Cardiovascular Disease Risk Charts 2004. British Hypertension Society Website
7. Familial hypercholesterolaemia: full guideline appendix F NICE (March 2010)
8. Tunstall-Pedoe H; The Dundee coronary risk-disk for management of change in risk factors. BMJ. 1991 Sep 28;303(6805):744-7. [abstract]

Acknowledgements