Patients who know they are on statins are more likely to report muscle pain and weakness than those who are unaware they are taking the drug, according to new research.
Researchers say the findings are consistent with a phenomenon known as the “nocebo” effect, where the expectation of side effects can make patients more likely to report them.
“It’s precisely the expectation of harm that is likely causing the increase in muscle pain”
The study, published in The Lancet, looked at data on different side effects from a trial of about 10,000 patients from the UK, Ireland and Scandinavia.
In the first phase of the trial, participants were randomly assigned statins or a placebo. Patients were followed for three years after which they were given a choice of taking statins or not.
Most of the original group were followed for a further two years, with two-thirds opting to use a statin.
During the initial “blinded” phase of the trial, the rate of muscle-related symptoms was similar whether patients received a statin or placebo.
However, during the “non-blinded” phase, muscle-related symptoms were 41% more common among people taking statins compared to those who were not.
The results suggested muscle pain and weakness were unlikely to be directly caused by statins but may be down to the nocebo effect, concluded the research team.
“Just as the placebo effect can be very strong, so too can the nocebo effect,” said lead author Professor Peter Sever, from the National Heart and Lung Institute at Imperial College London.
“This is not a case of people making up symptoms or that the symptoms are ‘all in their heads’,” he said. “Patients can experience very real pain as a result of the nocebo effect and the expectation that drugs will cause harm.
“What our study shows is that it’s precisely the expectation of harm that is likely causing the increase in muscle pain and weakness, rather than the drugs themselves causing them,” he added.
Questions over muscle-related side effects from statins
Professor Sever said the cholesterol-lowering drugs did have some side effects, including a small increase in the risk of diabetes. But he said that “overall the benefits greatly outweigh the harms”.
“Widespead claims of high rates of statin intolerance still prevent too many people from taking an affordable, safe and potentially life-saving medication,” he noted.
In a linked comment in the journal, Dr Juan Pedro-Botet, from the Hospital del Mar in Barcelona, and Dr Juan Rubiés-Prat, from the Universitat Autonònoma de Barcelona, said clinicians need to make patients aware of the possible side effects of statins “without raising negative expectations”.
“Furthermore, they should encourage patient understanding of the rationale for statin treatment, which could optimise and facilitate shared decision making on statin therapy,” they wrote.