The benefits of using statins, a class of popular cholesterol-lowering drugs, largely outweighs the risks, according to a study published in the American Heart Association’s journal Circulation: Cardiovascular Quality and Outcomes.

Researchers carried out the largest meta-analysis on statin side effects to date. Data was reviewed from 135 previous drug studies in order to analyze the safety of seven statins on the market.

Trials published between 1985 and early 2013 were reviewed by the researchers, which involved looking at nearly 250,000 patients. Some trials compared a statin with an inactive placebo (dummy pill), while others compared one statin against another.

The researchers found that simvastatin (Zocor) and pravastatin (Pravachol), had the best safety profile of the statins tested. The study’s lead author Huseyin Naci said this was particularly evident in patients who were prescribed low to moderate doses of these statins.

The study also revealed that statins were not linked to an increase in cancer risk.

Statins are a class of drugs used to lower cholesterol. They are widely used for the prevention of recurrent heart disease or stroke in patients.

The Jupiter Trial (Justification for the Use of Statins in Primary Prevention), found that 54% of cardiovascular disease patients had a lower chance of a heart attack, while 48% of patients had a lower chance of stroke.

Statins work by preventing the formation of cholesterol in the liver. They are very effective at lowering LDL cholesterol (the bad cholesterol), as well as lowering blood fats (triglycerides) and raising HDL cholesterol (the good cholesterol).

Some of the risks of using statins have been widely reported. For example, a study from the University of Waterloo in Canada revealed that statins may be linked to eye cataracts. Other research from the University of California also found that statins can cause fatigue and decreased energy when exercising.

However, senior cardiac nurse at the British Heart Foundation in the UK says of this most recent review of overall safety, that the evidence was reassuring.

She adds: “Side effects don’t routinely occur and the vast majority of people can take them safely, knowing the benefits outweigh the risks.”

The current researchers did though find a 9% risk of diabetes in statin users. They say that this compares with a previous study showing diabetes in only one in every 250 patients who use statins. Yet Naci says that statins have been proved to cut the rate of hospitalization and death in patients who have heart disease, which outweighs the risk of diabetes.

Lead author Naci adds:

“I am concerned that patients may misunderstand this small increase in risk and stop adhering to their medications.”

Additionally, it was found that statins were associated with a typically reversible increase in liver enzymes. However, Naci said this resulted in a very low rate liver toxicity in patients.

Naci says that although the benefits of statins clearly outweigh the risks at population level, individualizing such benefits and risks is more difficult.

He adds: “This brings into sharp focus the importance of identifying the individuals who stand to benefit the most from statin therapy. Although the risk of developing diabetes is low, what this risk would amount to over time is simply not known based on existing evidence.”