Between 5% and 20% of patients receiving statins report that they experience muscle-related intolerance, such as pain or weakness, which often results in discontinuation of treatment. But as these symptoms are self-reported, there has been doubt over the true incidence.
In a paper published in JAMA (online, 3 April 2016)
, researchers explored this by performing a crossover study in which 511 patients with a history of intolerance were randomly assigned to receive atorvastatin or placebo for ten weeks before switching to the other treatment.
Overall, 42.6% of patients experienced intolerable muscle symptoms during atorvastatin treatment, but not with placebo. However, 26.5% of patients only reported symptoms during the placebo phase, suggesting their symptoms were not statin related.
The researchers say their study may underestimate the incidence of atorvastatin intolerance as the dose was 20mg and symptoms are dose related.