Independent risk factors for simvastatin-related myopathy and relevance to different types of muscle symptom

SPS commentary:

The authors developed a novelty myopathy risk score, derived from the combination of the identified risk factors. Despite the strong association with myopathy (otherwise unexplained muscle pain or weakness with CK >10× upper limit of normal), this score was not associated with ‘other muscle symptoms’ (new unexplained muscle pain or weakness that was not associated with a diagnosis of ‘myopathy’) and they say this is consistent with evidence from randomised placebo-controlled trials that statin therapy does not typically cause such symptoms. They suggest that CK should be measured in those who report muscle symptoms and monitored in the small minority who have moderately elevated levels, but otherwise they should be encouraged to continue taking their statin therapy.

A related editorial notes that RCTS may under-represent groups at an increased risk of statin-associated muscle symptoms (SAMS); in addition mild muscle symptoms may have escaped adjudication but be highly relevant for patients and their medication adherence. The authors comment that “irrespective of CK and of the highly prevalent nocebo effects, each patient reporting with SAMS requires attention and time—not for reasons of safety but in order to support medication adherence and to reach LDL cholesterol goals.”