Are Chronic Pain Syndromes the Reason for Statin-Associated Muscle Symptoms?

Background: Statin induced myalgia is defined as muscle pain without elevation of serum creatine phosphokinase levels, and is a well-known complaint among statin users. Chronic pain syndromes affect a high percentage of the population; and it may be possible that these pain syndromes confound the reports of statin induced myalgia. We sought to compare the occurrence of chronic pain among patients on statin therapy who developed myalgia with those who did not. Methods: This study included 112 statin-treated patients, followed up at the clinic of the Lipid Center in Sheba Medical Center. Fifty-six of the subjects had a diagnosis of statin associated muscle symptoms (SAMS) and 56 did not. Verified questionnaires were used to assess the diagnoses of fibromyalgia, pain intensity, functional impairment, anxiety and depression in the study population. Results: Patients with statin myalgia were more likely to fulfil the diagnostic criteria for fibromyalgia than patients without statin myalgia (11 (19.6%) vs. zero, respectively). Patients in the SAMS group also exhibited higher levels of anxiety and depression in comparison with the control group. Female sex, higher scores on the Brief Pain Inventory pain intensity scale, and a Hamilton rating scale level indicative of an anxiety disorder were found to be significant predictors for fibromyalgia in patients suffering from statin myalgia. Conclusion: A significant percentage of patients, diagnosed with statin myalgia actually fulfilled the diagnostic criteria for fibromyalgia, depression or anxiety disorder. Detection of these patients and treatment of their primary pain disorder or psychiatric illness has the potential to prevent unnecessary cessation of effective statin therapy.