Cardiovascular health and Framingham risk score

What is a Framingham risk score?

A Framingham score shows the risk of developing heart disease over the next 10 years. The score is calucalted based on risk factors identified in a large, long-term study which began in 1948. It is considered a reliable, accurate benchmark for assessing cardiovascular risk in the general population.

The ethnic background of the population used for this study was predominantly white American.

Online risk calculators

The University of Edinburgh has a selection of cardiovascular disease risk calculators developed with the British Joint Societies (collected professional heart health institutions):
cvrisk.mvm.ed.ac.uk/calculator/calc.asp

These include calculators for Framingham risk score, risk of myocardial infarction (MI, heart attack), stroke and a Scotland-specific calculator (ASSIGN) that accounts for family history and social deprivation (ie post code).

Results may not be not completely accurate for HIV-positive people, but are a good baseline.

ETHRISK is a modified Framingham calculator for British black and minority ethnic groups developed by the University of Bristol:
www.epi.bris.ac.uk/CVDethrisk/CHD_CVD_form.html.

This calculator is only for people without diabetes or a previous history of cardiovascular disease.

Downloadable calculator

HEART UK has a downloadable calculator for use on a PC which assesses risk according to the British Joint Societies' guidelines:
heartuk.org.uk/new/pages/prof/jbs_cv_riskassessor.html

What counts as low, medium or high risk?

• High risk: more than 20% risk of heart disease over 10 years
• Medium risk: 10-20%
• Low risk: less than 10%

Risk factors for cardiovascular disease

General risk factors for heart disease in HIV-positive people are the same as for people who are HIV-negative.

Fixed risk factors:

• Older age (men over 45, women over 55)
• Gender (men are at higher risk at the same age)
• Family history of heart disease

Modifiable risk factors:

• Smoking
• High levels of fat in blood - ie high cholesterol and/or triglycerides
• Amount of regular exercise
• High blood pressure, especially diastolic blood pressure
• High levels of sugar in blood, insulin resistance and diabetes

Recent studies suggest depression increases the risk of heart attack.

HIV treatment and cardiovascular risk

HIV itself can increase the risk of cardiovascular disease and heart attck. Overall, treating HIV tends to reduce cardiovascular risk. Some drugs used in combination therapy can increase cardiovascular risk.

The benefits of combination therapy far outweigh the possible small increased risk of heart disease for most HIV-positive people:

• The SMART study found that using HIV treatment with an undetectable viral load was protective of heart disease compared to not being on treatment or having a detectable viral load. This is supported by other research.
• The D:A:D study showed a small additional increase in risk of heart disease from each year on protease inhibitor treatment (+10%), but not from using NNRTIs.
• In 2008 D:A:D also reported an increased risk from current or recent use of the nukes abacavir (+90%) or ddI (+45%).
• Making lifestyle changes that minimise risk factors are now strongly recommended as part of a long term plan for managing HIV-positive patients.

BHIVA guidelines recommend:

• Assessment of cardiovascular health before starting treatment.
• Routine monitoring of lipids, blood sugar and other risk factors.
• Assessment of cardivascular risk using the Framingham calculator or the British Joint Societies' risk prediction charts.
• Antiretroviral treatment for people with cardiovascular disease or high cardiovascular risk even if CD4 count is over 350 cells/mm³.
• Caution using Kivexa or abacavir for people with a high cardiovascular risk.
• Management of cardiovascular risk by: quitting smoking, other lifestyle changes (diet, exercise, alcohol intake), careful selection of first-line combinations, changing antiretrovirals if needed, use of fibrates and statins, managing diabetes and high blood pressure in line with national guidelines.

Lipids and cardiovascular risk

Changes in lipids (blood fats - cholesterol, triglycerides) can contribute to cardiovascular risk. Lipids are measured in mmol/l. Desirable levels:

• Total cholesterol: under 5.2 mmol/l (increased risk over 6.9 mmol/l)
• LDL cholesterol: under 3.4 (increased risk over 3.4)
• HDL cholesterol: over 0.9 (increased risk under 0.9)
• Fasted triglycerides: under 2.2 (increased risk over 4.4)

More information

i-Base - Heart disease
www.i-base.info/guides/side/heart.html

i-Base - Cholesterol and trigycerides
www.i-base.info/guides/side/triglycerides.html

HEART UK - Risk charts
heartuk.org.uk/new/pages/prof/risk.html

European ADS Clinical Society - Metabolic guidelines
www.eacs.eu/Guidelines_Livret/index.htm

Updated: 25 October 2008

Based on i-Base treatment guides, British Joint Societies guidelines, BHIVA guidelines, American Journal of Cardiology