HOW TO PREVENT CANCERS

by Cathy Johnson

Statins are the most commonly prescribed drugs in Australia. But some people who are unlikely to benefit are taking them, while other high-risk patients are not being picked up.

Statins are medicines that lower the amount of cholesterol in your blood to help reduce your risk of having a heart attack and stroke. While there are other cholesterol lowering medications available, statins are the most widely used.

Around 3 million Australians take statins, and this costs our health system more than $1 billion a year. At least four in every ten Australians over the age of 65 take them.

Too much cholesterol in your blood, especially a type called low-density lipoprotein (LDL) or 'bad' cholesterol, can cause fatty deposits to build up in your arteries. These deposits can result in blockages in arteries that lead to your heart and brain, causing a heart attack or stroke.

Statins work by reducing the amount of LDL cholesterol your body makes in your liver, thereby reducing the amount of cholesterol you have in your blood.

There are a large number of different brands but all statins have one of five different active ingredients: atorvastatin, fluvastatin, pravastatin, rosuvastatin and simvastatin.

Statins are prescribed for people who have already had a heart attack or other cardiovascular event in the past. Cardiovascular events include heart attacks, strokes, mini strokes (also known as transient ischaemic attacks) and angina (chest pain from inadequate blood supply to the heart).

You might also be prescribed statins if you have a number of important risk factors for cardiovascular events, such as diabetes, high cholesterol and high blood pressure, or a family history of cardiovascular problems, says Dr Andrew Boyden, a clinical advisor with the non-profit group NPS MedicineWise. Under new Australian guidelines introduced in 2012 it is a person's absolute risk of a cardiovascular event that influences whether prescribing statins is appropriate, rather than a single measure, such as someone's blood cholesterol level. (The absolute risk is determined by a complex formula which weighs up aspects of a person's health and family history.)

However, there's evidence many Australian GPs are not following the new guidelines.

"Most GPs say they know about AR [absolute risk] and say they're doing it, but when you drill down a little further you find that only about five per cent to 10 per cent are using an AR calculator," Dr Robert Grenfell, chair of the National Vascular Disease Prevention Alliance (NVDPA), told the online magazine for doctors MJA Insight recently.

This means some people who are unlikely to benefit from statins are taking them, while some high-risk patients are not being identified.

A person with a higher cholesterol level may not need statins because their absolute risk of a heart attack or stroke is low, Boyden says. But someone with lower blood cholesterol may still benefit from statins because other factors may mean their absolute risk of heart attack or stroke is nonetheless high and therefore any reduction in cholesterol is still useful.

In a 2011 article in Australian Prescriber journal, Associate Professor Jane Smith of Bond University, put it another way: "In people at high risk, especially those who have heart disease, statins lower cholesterol and the chance of heart attack. But in other people, it may not be beneficial to focus only on high cholesterol to determine whether statins should be used."

"Statin treatment in those with a lower risk offers limited benefit and may result in harm such as cataracts or muscle damage," she says.

As well as cataracts and muscle damage, other side effects associated with statin use include liver problems, a small increased risk of diabetes and memory problems.(The memory problems may be reversible when the person stops taking the statins.)

Side effects are more likely in people aged over 70, especially those taking several other medicines, and this has led some health experts to suggest statins' side effects may outweigh the benefits in some older people.

Statins lower the chance of a heart attack or death in older people who have already had a heart attack, but their benefit in older people who do not already have heart disease is less clear, University of Sydney and Royal North Shore Hospital researchers Associate Professor Sarah Hilmer and Dr Danijela Gnjidic said in another Australian Prescriber article earlier this year.

While you can lower your blood cholesterol levels through diet and to a lesser extent exercise, many people at higher risk of a cardiovascular event also need help from a cholesterol-lowering medicine, Boyden says.

Statins can lower blood cholesterol more powerfully than lifestyle measures, but exercise and a healthy diet are still very important for people taking statins, he says.

This is because exercise and diet may help keep blood cholesterol even lower. Exercise and diet also independently lower the odds of heart attacks and strokes in a person, quite apart from their influence on blood cholesterol.

Following a healthy diet and getting enough exercise is important for everyone, regardless of their cholesterol levels, Boyden says.

The guidelines say

regardless of a person's absolute risk level, treatment should begin with lifestyle interventions.people at high risk (those with >15% risk of a cardiovascular event within five years) are recommended to be treated simultaneously with lifestyle interventions and with therapies aimed at reducing both blood pressure and blood cholesterol. This is generally regardless of the level of their blood pressure or blood cholesterol.people at moderate risk (those with 10-15% risk of a cardiovascular event within 5 years) should be given the opportunity to reduce their risk by following lifestyle advice, with drug therapy only considered if their risk has not reduced in three to six months or if they have specific additional factors.Updated: 04/11/2013