Cholesterol-lowering statin drugs are associated with an increased risk of diabetes, but this risk is outweighed by the protection they offer against coronary events such as heart attack and stroke, confirms a new large-scale study. The same study also showed that the National Institute for Health and Clinical Excellence (NICE)-recommended statin does not protect against coronary events as effectively as an alternative statin amongst patients taking high doses.

Statins are prescribed to people at risk of cardiovascular disease such as heart attack and stroke to reduce levels of so-called “bad” cholesterol.

 



Researchers from St George’s, University of London, working with colleagues at the University of Glasgow, analysed five statin trials published between 2004 and 2010. They concluded that people taking higher doses of statins were 12 per cent more likely to develop diabetes than those taking moderate doses.

The researchers stressed that patients should not reduce their dose. The risk this poses to overall health is low, especially when compared to the beneficial effects statins have on reducing the risk of serious heart problems.

The researchers also looked at whether the diabetes risk varied between two frequently prescribed statins – atorvastatin and the NICE-recommended simvastatin. This showed that the diabetes risk was the same but that atorvastatin reduced the risk of a coronary event by 17 per cent more than the NICE-recommended drug amongst patients on high doses.

The study is published online tomorrow (22 June) in the Journal of the American Medical Association.

The same researchers have previously shown that statins could increase the risk of developing diabetes, but there was the possibility that this was a chance finding and more investigations were needed to provide a definitive answer.

This latest study adds to this knowledge by assessing if the risk of developing diabetes varies between moderate and high dosage. “Linking the risk of diabetes to the dosage of statin proves that the relationship found in the previous study is not a chance relationship and that statins are related to an increase in the risk of diabetes,” said lead researcher Professor Kausik Ray from St George’s, University of London.

The analysis, which involved 32,752 individuals across the five studies, found that one extra case of diabetes was diagnosed for every 498 people treated on high doses of statins compared to those on moderate doses.

It also showed that the heart health benefit of high doses was much higher than the diabetes risk, with the high dose preventing one case of heart disease or stroke for every 155 people treated

Professor Ray said: “There is not yet a clear explanation for why statins may cause diabetes in some patients. Patients on high doses of statins should continue taking their medication as normal and complement this with more regular screening for diabetes.”

The analysis then compared the risk of patients developing diabetes when taking either the NICE-recommended high-dose simvastatin versus moderate doses of stains, or high doses of the alternative versus standard doses of the other statin. This was also compared to the protection from cardiovascular disease offered by both drug options.

They found that the risk of developing diabetes increased by a similar amount with both high-dose simvastatin and high-dose atorvastatin, but high-dose atorvastatin was better at preventing conorary events compared with high-dose simvastatin. Atorvastatin reduced the risk of cardiovascular events by 22 per cent, whereas simvastatin reduced this risk by five per cent.

Professor Ray said: “Currently NICE recommends simvasatin 80mg as it is the least expensive option in patients with established heart disease. However, this research shows that it is not the best option for patients.”