To answer these questions, the researchers analysed millions of data from thousands of participants in 23 large-scale randomised clinical trials of statin treatments.

They pored over data from 19 large randomised double-blind trials of statins versus a placebo, and four randomised double-blind trials of higher strength statins versus lower strength statins, involving 154,664 participants overall.

By looking at the data for every trial participant, the researchers were able to look at variations in the effects of statin therapy on diabetes status in different types of people, for example by age, sex, body mass index (BMI), and background risk of developing diabetes.

What did they find out?

Statin therapy causes a small increase in glycaemia (blood sugar levels), which translates into a moderate increase in the rate at which individuals are diagnosed with new onset diabetes, the researchers found.

Participants who were given lower doses of statins had a 10 percent higher risk of developing newly diagnosed diabetes when compared with participants who were given a placebo. Participants who were given higher doses of statins had a 36 percent higher risk of diabetes compared with placebo.

The researchers also found:

• For all statin doses, the increases in risk of new-onset diabetes appeared similar across all types of people, irrespective of age, sex, BMI, and blood sugar levels
• The same mechanism can also cause worsening blood sugar levels among those with diabetes: participants who already had diabetes at the start of the trials and who received lower doses of statins had a 10 percent greater risk of worsening blood sugar levels and those who received higher doses had a 24 percent greater risk of worsening blood sugar levels

Christina Reith, Associate Professor at Oxford Population Health and Honorary Consultant in Pharmaceutical Medicine, said: “This study demonstrates the likely mechanism by which statin therapy increases new cases of diabetes. We have confirmed that this is driven by a very small rise in blood sugar levels, leading some individuals receiving statins to cross over from just below to just above the threshold for diagnosing diabetes.”

Research from 2017 and a study from 2020 also found that higher doses and longer use of statins may be linked to an increased risk of developing diabetes.

While the overall chance of developing diabetes was small, atorvastatin and rosuvastatin carried the largest risk.

Editor’s take 

The results of the latest meta-analysis reflect that statin use does come with the risk of side effects.

However, as is the case with all medications, the benefits must be weighed against the risks, and most people tolerate them well.

I would defer to the consensus on this one. For example, the British Medical Journal (BMJ) says statins are associated with a small increased risk of side effects in patients without a history of heart disease, but these effects are mild compared with the potential benefits of treatment in preventing major cardiovascular events.

You should discuss the benefits and risks of taking statins with your doctor before you start taking the medicine.