HEART OF THE MATTER
HIV and combination therapy can alter blood
fats that can in turn lead to an increased risk of heart disease. Learn how
to reduce this risk with our simple guide
Words Robert Fieldhouse
Image Craig Hewitt
Once
it was enough to just keep an eye on our CD4 count and viral load to tell
us if we needed to start or switch therapy. Nowadays, HIV clinics will also
regularly monitor a range of other blood markers such as blood fats, also
known as lipids, like cholesterol. These tests can also show how well our
bodies are coping with the virus and HIV medications.HIV itself can alter
the levels of certain fats in the blood and some HIV meds may have a positive
or negative impact on lipids too. It’s important our blood fats are
monitored before we start therapy and
regularly while we are on it. You can ask at your clinic to find out if your
blood fats are within the normal range.
What are cholesterol, lipoproteins and blood lipids?
Cholesterol is made in the liver from the saturated fats in our food. It is
used in the production of sex hormones, as well as the repair of cell membranes.
Too much can increase our risk of developing
coronary heart disease. Cholesterol uses the blood to travel around the body
using ‘vehicles’ made up of proteins. These combinations of cholesterol
and proteins are called lipoproteins.
There are two kinds of lipoproteins:
low-density lipoproteins (LDL) and high-density lipoproteins (HDL). We often
hear cholesterol referred to as ‘good’ or ‘bad’. HDL,
or ‘good’ cholesterol, clears cholesterol from the arteries to
the liver, where it is removed from the body. LDL, or ‘bad’ cholesterol,
carries cholesterol from the liver to the cells and is associated with hardening
of the arteries. This may lead to angina, heart attack and stroke.
Blood lipids is the collective term for all fatty substances in the blood
including LDL and HDL cholesterol and triglycerides. Triglycerides are one
of the basic building blocks from which fats are formed. Having both high
cholesterol and triglycerides can further increase your risk of coronary heart
disease. The risk is greatest if you have a low HDL cholesterol and high LDL
cholesterol.
How are blood fats measured?
By blood test. The result is referred to in units described as millimols (mmol/l)
per litre of blood. The average blood cholesterol level in the UK is 5.5mmol/l.
You should aim to have:
• A total cholesterol under 5mmol/l
• An LDL level under 3mmol/l
• An HDL level above 1 mmol/l
• A triglyceride level under 2 mmol/l
You need to take a series of cholesterol tests into account before you decide
to make changes to your lifestyle such as altering your diet or starting lipid-lowering
drugs.
Total cholesterol: HDL ratio
Doctors may assess our risk of coronary heart disease by measuring the ratio
of our total cholesterol to our HDL level. It is possible for us to work this
out ourselves by dividing your total cholesterol by your HDL cholesterol level
(see box below). Ideally this figure should be less than 4.5 in men or 4 in
women. The higher the level, the greater your risk of coronary heart disease.
Risk of heart disease against ratio of total cholesterol to HDL cholesterol
Risk level Men Women
Very low <3.4 <3.3
Low 4.0 3.8
Average 5.0 4.5
Moderate 9.5 7.0
High >23 >11
Peter, 38, had been taking HAART for six years when his doctor told him his
total cholesterol to HDL ratio had risen to 8.2 (average to moderate risk).
Rather than change his HIV treatment immediately, his doctor suggested he
make changes to his lifestyle. “I cut down on alcohol and improved my
diet with more fruit and vegetables and less fatty foods, and started working
out three times a week. After three months my results came back at 6.5 which
meant I could stay on my current HIV meds and continue my new routine. I’m
still trying to give up smoking but it’s difficult. My doctor keeps
telling me this is the most helpful thing I can do for my heart.”
What is the effect of HIV on lipids?
Before antiretrovirals (ARVs), people with Aids often had raised LDL ‘bad’
cholesterol and declining HDL ‘good’ cholesterol. Typically, after
someone becomes HIV positive, their total cholesterol level declines and their
triglyceride level increases. Studies show that when we begin HIV therapy,
a lot of the cholesterol increase may be due to our cholesterol simply returning
to its normal level for our age.
Lifestyle changes you can make to improve cholesterol levels
1) Healthy eating
It may be possible to reduce our total cholesterol by between five and 10
per cent simply by making changes to our diet. Reduce fat intake and replace
saturated fats (such as butter) which increase LDL with monounsaturated fats
(such as olive oil or avocado) which lower LDL but don’tlower HDL. Increase
your intake of polyunsaturated fats, (like cornflower or sunflower oil) which
lower LDL (but remember they also lower HDL cholesterol, which ideally we
want to keep quite high). We can increase our intake of omega-3 fats which
can be found in oily fish such as mackerel, herring, salmon and sardines.
If you don’t eat fish, try linseeds and flaxseeds. A recent study showed
that it’s possible for people on HAART to reduce their triglycerides
by taking two 1g capsules of omega-3 fish oil supplements three times a day.
Triglycerides fell by an average of 26 per cent, and one in five of the trial
participants who started with elevated triglycerides saw their levels normalise
over eight weeks.
Reducing alcohol intake may reduce triglycerides but a glass or two of wine
or beer each day can actually increase our levels of HDL ‘good’
cholesterol. A high-fibre diet (porridge, beans, fruit and veg) may also help
reduce the amount of cholesterol absorbed from the intestine into the bloodstream.
If you are overweight, losing weight can help reduce cholesterol levels and
the risk of a heart attack.
2) Exercise
Regular exercise such as cycling, swimming, or walking briskly for 30 minutes
a day at least five times a week can increase your HDL but has not been shown
to decrease levels of LDL. Regular exercise can halve your risk of a heart
attack.
3)
Smoking
Stopping smoking can halve our risk of having a heart attack within one year
of quitting. Those who seek help are more likely to be successful than people
who try to quite without any support. Ask your doctor or get advice from a
counsellor. Nicotine replacement therapy and drug therapy with bupropion have
been shown to work while alternative methods such as hypnotherapy and acupuncture
can also help.
When should I take additional medication?
Medication
for elevated cholesterol is
normally prescribed only when the lifestyle changes we have discussed have
failed to make a significant impact on reducing cholesterol levels. They have
been shown to reduce LDL by more than 20 per cent. Statins are the main class
of drug used, but these should not be used by people with liver disease or
pregnant or breastfeeding women. Pravastatin appears to be the safest statin
if you are taking a protease inhibitor or PI (see Treatment News, page 38).
Other drugs used to treat raised cholesterol levels include bile acid binding
drugs and fibrates.
Impact of HIV treatment
Some studies show thickening of and damage to the arteries in people taking
some PIs. It is suggested these people may be at an increased risk of developing
heart disease, though these drugs have not been in use for long enough for
us to truly know what the longer-term risk will be. A large study, D:A:D,
which included
information on over 23,000 people living with HIV, found heart attack risk
increased by 26 per cent with each additional year on ARVs. This sounds scary,
but the researchers concluded that the absolute risk of a heart attack remained
low and did not outweigh the effectiveness of HIV therapy. And being male,
having high cholesterol, diabetes, and smoking all still seem to increase
the risk of a heart attack much more significantly than HIV therapy. PIs can
increase cholesterol and triglyceride levels, usually within weeks of starting
therapy. However, lifestyle changes can help cut these. If your blood fat
levels don’t improve, your doctor may decide to switch therapy if appropriate
or introduce a statin.
If you are concerned about how your HIV therapy may be impacting upon your
risk of heart disease in the future, discuss your options with your doctor.
• For information on giving up smoking, visit www.quit.org.uk
• This article was supported with an unrestricted educational grant
from GlaxoSmithKline. Code: HIV/ART/05/23336/1
