High doses of statins increase risk of diabetes

BMJ Group News

What do we know already?

Anyone with too much bad cholesterol in their blood is more likely to have a heart attack or a stroke. Drugs called statins are the best way to cut levels of bad cholesterol and reduce the risk of these cardiovascular problems.

Typically patients are prescribed a moderate dose (such as 10 mg of atorvastatin or 20 mg simvastatin) but this can be increased to a high dose (80 mg) if cholesterol levels haven’t come down enough.

High-dose statin treatment reduces the likelihood of cardiovascular problems more than moderate doses. However, recent research has shown that statin treatment increases the risk of someone developing diabetes, and that this risk is highest among those on high doses.

Researchers have now pooled the results of five large studies to see what effect moderate and high doses of statins have on a patient’s risk of developing diabetes or having further cardiovascular problems, such as a heart attack or stroke.

What does the new study say?

The results confirm earlier suggestions: high-dose statin treatment reduces the likelihood of cardiovascular problems but causes more patients to develop diabetes.

There were 2 extra cases of diabetes each year, for every 1,000 people taking high-dose statins, compared with people taking moderate doses. But this was balanced by 6.5 fewer heart attacks, strokes or other major cardiovascular problem, for every 1,000 people taking high doses, every year.

The figures came from a total of 32,752 patients with cardiovascular problems, who were started on moderate or high-dose statin treatment and then followed up for around five years.

How reliable is the research?

This was a systematic review and meta-analysis, which is the best way to combine information from a number of studies. All the studies in the review were randomised controlled trials, which provide a good way to find out the effects of a treatment. So the results should be reliable.

Where does the study come from?

The study was done by doctors at a number of American and European universities and medical schools. It was published in JAMA (Journal of the American Medical Association). It was supported by grants from the US National Institutes of Health.

What does this mean for me?

It’s still not clear whether high-dose statins increase diabetes risk in everyone or if there is a particular group who are more at risk. What is clear is that statins do offer benefit most people with high cholesterol.

If you’re not sure whether you are taking a high or standard dose, ask your pharmacist or doctor. The increased diabetes risk only affects people taking a high dose.

The report’s authors recommend that doctors watch for symptoms of diabetes in patients on high-dose statin treatments.

What should I do now?

Talk to your doctor if you are on an intensive dose of a statin (for example, 80 mg a day of simvastatin or atorvastatin) and you are unhappy about your risk of diabetes.

Symptoms of diabetes include feeling thirsty, going to the toilet frequently, and feeling very hungry or tired. If you have these symptoms, see your doctor.