A Prospective Single-Center Study of Incidence of Atorvastatin-Induced Myalgia in Korean Patients: Application of the Statin Myalgia Clinical Index

Abstract

Background: Statin-induced myalgia is a common cause of discontinuation and a barrier that interferes with long-term treatment. The incidence of myalgia reported by previous atorvastatin trials in Korea ranged from 0.8% to 3.4%. This study assessed the incidence of myalgia after atorvastatin was administered to Korean patients with dyslipidemia. In addition, the Statin Myalgia Clinical Index (SMCI) was used to assess the likelihood that a patient’s myalgia was caused by atorvastatin.Methods: Dyslipidemic patients were eligible to participate if they were statin-naïve or treated with statins other than atorvastatin. Muscle complaints were assessed at the baseline, the 10-weeks visit and the final follow-up visit (16 weeks or later). The SMCI score was calculated if a patient developed myalgia, which was rated as probable, possible or unlikely related to the statin.Results: A total of 89 patients were analyzed. The atorvastatin doses ranged from 10 to 80 mg. Six (7%) patients reported new and unexplained muscle pain. Information on the timing of myalgia relative to stopping was unavailable in two patients. After excluding these two patients, three (3.4%) out of 87 patients were classified by the SMCI as having possible or probable atorvastatin-associated myalgia.Conclusions: In this study, the incidence of myalgia was higher than the incidences reported by the previous trials in Korea. However, the incidence of statin-associated myalgia assessed using SMCI was comparable to those of the trials. The SMCI may help diagnosis of statin-associated myalgia in clinical practice and optimize treatment for patients with myalgia.