Cholesterol and triglycerides

About cholesterol & triglycerides
Fasted triglyceride levels
Cholesterol
Changning HIV drugs in your combination
Diet, exercise and lipid lowering drugs

More about lipodystrophy:

About cholesterol and triglycerides

Cholesterol and triglycerides are two types of fats (lipids) that can be measured in blood and plasma.

They should be measured before starting or changing treatment, and repeated a month afterwards. Routine monitoring for someone on stable treatment should involve checking levels of cholesterol and triglycerides every 3-6 months.

Most clinics will do this at the same time as your CD4 and viral load, but you may need to check that this is being done. These tests are best done fasted so don’t eat or drink anything for breakfast on blood test days.

Management of lipid levels should be part of an assessment of your risk for heart disease.

This is generally related as much to other risk factors, as to any single elevated blood test.

Fasted triglyceride levels

High triglycerides are linked to increasing the risk of heart disease. For each increase of 1.1 mmols/L the 10-year risk of a heart attack increases by about 25% in men and 60% in women.

Although there is a lot of individual variability target fasted levels of under 2.2 mmol/l are considered normal and of 2.2-4.4 mmol/l are borderline. Above this, the risk of heart disease increases. Levels above 11 mmol/L are considered very high.

Untreated HIV also causes triglycerides to increase.

Cholesterol

Total cholesterol (TC) is measured first. If these results are high then a further test will break this down into two different types of cholesterol:

High Density Lipoprotein (HDL) is a ‘good’ cholesterol because it removes fats from your arteries;
Low Density Lipoprotein (LDL) is ‘bad’ cholesterol and is a small molecule that carries fats from the liver to other parts of your body and can lead to heart disease.

Target levels for total and LDL cholesterol and desirable levels for HDL cholesterol and triglycerides are shown in Table 1. Target levels are set lower for people who already have high cardiovascular risk due to other factors.

The TC:HDL ratio is used to determine the importance of using lipid lowering drugs, but is not used for monitoring afterwards.

Table 1: Target/desirable levels for fasted lipids

Total cholesterol: Target level: under 5.2 mmol/l; Increased risk of cardiovascular disease: over 6.9 mmol/l
LDL cholesterol: Target level: under 3.4 mmol/l; Increased risk of cardiovascular disease: over 3.4 mmol/l
HDL cholesterol: Target level: over 0.9 mmol/l; Increased risk of cardiovascular disease: over 3.4 mmol/l

Cholesterol is measured in millimoles/litre (mmol/l):

Changing HIV drugs in your combination

Lipids generally improve after switching away from HIV drugs that have caused this change.

This usually involves switching from a protease inhibitor combination - particularly if it includes ritonavir - to nevirapine, abacavir or atazanavir/r.

Abacavir may have a greater impact on reducing cholesterol, and nevirapine may help with increasing HDL (good cholesterol). The debate on the impact of different strategies on reducing risk for heart disease is likely to develop and change over the next few years.

This became more complicated in 2008 when the D:A:D study reported that abacavir was independently associated with a 90% increased risk of heart disease. This is discussed on in the section on heart disease.

Atazanavir is a once-daily protease inhibitor that is being widely used because it does not cause lipid increases, although the boosting dose of 100mg ritonavir reduces this benefit.

The choice of individual drugs will depend on your previous treatment history and previous history of resistance.

Diet, exercise and lipid lowering drugs

Cholesterol and triglyceride levels can often be improved or controlled by reducing fat and cholesterol in your diet and by starting or increasing exercise.

Omega-3 supplements can also have a significant reduce triglyceride levels. This may be much more efficient than trying to obtain sufficient quantities of omega-3 from diet alone.

For example, a 4 g daily dose Omacor, (90% omega-3 acid ethyl esters) is equivalent to 150g mackerel, 700g tuna, 210g herring, 1.1 kg cod, 280g salmon, 1.7kg eel or 850g shrimps.

If diet, supplements, and exercise are not enough, then lipid-lowering drugs (fibrates to reduce triglycerides and/or statins to reduce LDL cholesterol) are recommended.

Lipid-lowering drugs need to be prescribed by an HIV-specialist as they can interact with HIV drugs. For example some statins should never be used and some require increased or decreased dosing when used with PIs or NNRTIs.

Studies are also looking at metformin (an insulin sensitising drug), rosiglitazone and growth hormone.

A study of HIV-positive men in a study looking at the effects of exercise and testosterone found that testosterone significantly reduced levels of ‘good’ cholesterol (HDL). This is a concern for people with lipodystrophy who already have elevated triglycerides and ‘bad’ cholesterol (LDL).

Although muscle gain and fat loss were greater in the testosterone group, levels of good cholesterol increased in people who used exercise without testosterone, and this may be more appropriate for people with lipodystrophy.

Although anabolic steroids can increase muscle mass they can also reduce fat, and have the potential to worsen lipoatrophy and lipid levels.

Improved blood lipids have not so far shown an improvement in either fat loss or fat accumulation.

For further information see the European metabolic guidelines:
The European AIDS Clinical Society (EACS)
http://www.eacs.eu