Muscle pain in people on statins may be genetically linked
New genetic study is fueling debate over muscle pain reported by many people taking popular cholesterol-lowering drugs called statins.
About 60% of people of European descent carry a genetic variant that can make them more susceptible to muscle pain in general. But counterintuitively, these people had a lower risk of muscle pain when taking statins compared to placebos, the researchers report on August 29 in the European Journal of the Heart.
Millions of people take statins to lower cholesterol and fight hardening of the arteries. But up to 78 percent of patients stop taking the drug. One of the common reasons for stopping drug use is side effects, especially muscle pain, says John Guyton, clinical lipidologist at Duke University School of Medicine.
However, it is not clear whether statins are causing the pain. In one study, 43 percent of patients who had muscle pain while taking at least one type of statin also experienced pain from other types of statin (NS: 05/13/2017, p. 22). But 37% of people with muscle pain in this study had pain unrelated to statin use. Other clinical trials have found no difference in muscle pain between people taking statins and those not taking them.
The new study suggests that genetic factors, especially those involved in the immune system maintaining and repairing muscle, may affect how people respond to statins. âThis is a major breakthrough in our understanding of myalgia,â or muscle pain, says Guyton, who was not in the study.
People with two copies of the common form of the gene LILRB5 tend to have higher than usual blood levels of two proteins released by injured muscles, creatine phosphokinase and lactate dehydrogenase. Higher levels of these proteins can predispose people to more aches and pains. In a review of data from several studies involving white Europeans, people with duplicate copies of the common variant were almost twice as likely to have sore muscles when taking statins than people with a less common variant. , Moneeza Siddiqui of the University of Dundee School of Medicine. in Scotland and his colleagues discovered.
But when researchers looked at who had pain when taking statins compared to placebos, those with two copies of the common variant appeared to be protected from the muscle pain associated with statins. Why is not clear.
People with double copies of the common form of the gene who experience muscle pain may stop taking statins because they mistakenly think the drugs are causing pain, said study co-author Colin Palmer of the University of Dundee in a press release.
The less common version of the gene is linked to reduced levels of muscle damage proteins and should protect against myalgia. Still, people with this version of the gene were the most likely to develop muscle pain specifically related to taking statins during the trials.
The finding suggests that when people with the less common variant develop muscle pain when taking statins, the effect is really from the drugs, the researchers say.
But researchers still don’t know the details of how the genetic variants promote or protect against myalgia on statins. Neither version of the gene guarantees that a patient will develop side effects – or that they will not. The team is proposing further clinical trials to unravel the interactions between the gene and the drugs.
More studies are needed before doctors can add the gene to the list of tests patients undergo, Guyton says. âI don’t think we’re ready to put this genetic testing into clinical practice at all,â he says. Right now, âit’s much easier to just give the statin to the patientâ and see what happens.