There is growing debate about whether doctors should prescribe statins to otherwise healthy older people to reduce their risk of developing their first heart attack or stroke.
Now the debate has reignited with the publication of a new analysis that casts doubt on their benefit for people over the age of 65, and raised concern of the potential for harm in people aged over 75.
Statins are the most commonly used cholesterol lowering medications in Australia. In 2010-2011 they were taken by 2.6 million Australians with 16 million scripts dispensed from June 2011 to June 2012.
They are prescribed to lower blood lipid levels and so reduce people’s chances of heart disease, including stroke, and to prolong life.
In particular, this class of drugs inhibits how the body makes low-density lipoprotein cholesterol or bad cholesterol.
Different statins reduce bad cholesterol to different extents. For example, atorvastatin and rosuvastatin produce larger reductions in bad cholesterol per milligram of drug than a different statin, pravastatin (about 50% vs 30%).
Further reading: Some things you should know about statins and heart disease
The issue of whether to prescribe statins for older people is particularly important given the growing segment of our population living into their 70s and 80s.
About one third of Australians over the age of 70 years are taking statins. And they could potentially be used by more older people as, based on their age alone, these are the people at highest risk of heart disease or stroke.
In people who already have heart disease or who have had a stroke, the benefits of statins are clear. Taking statins reduces your chance of another cardiovascular event whatever your age.
Doctors justify prescribing statins for this group by looking at a figure called the “number needed to treat”. In the case of statins, researchers calculate 28 people with existing heart disease or who had had a stroke would need to be treated for five years to prevent one death, a figure low enough to warrant treatment.
Mixed evidence
In people without heart disease or who have not had a stroke, the benefits of statins are less clear for those aged 70 years or older. Most national and international guidelines, including those from the Heart Foundation, have not been able to make strong recommendations to guide prescribing for older people. And any recommendations they do make are mostly based on trials of statins in people under the age of 70.
Some trials including older people without heart disease have reported no benefits whereas others have reported large benefits.
To complicate things further, pooling results of two of these trials finds statins reduce cardiovascular events in people aged under 65 years (by about 25%), 65-70 years (by about 50%) and over 70 years (by about 25%).
Due to the conflicting figures, researchers have not pooled the results to calculate a “number needed to treat” for healthy older people taking statins to prevent their first heart attack or stroke.
The debate about the benefits of statins for older people also needs to take into account the increased likelihood of side-effects from medications in this age group.
Researchers have not well studied side effects with statin use in older people. However, the issues most likely to be of concern to older people are muscle aches and weakness, muddled thinking and diabetes.