Absence of anti–HMG-CoA reductase autoantibodies in severe self-limited statin-related myopathy

Introduction: Patients with self-limited statin-related myopathy improve spontaneously when statins are stopped. In contrast, patients with statin-associated autoimmune myopathy have autoantibodies recognizing 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) and usually require immunosuppressive therapy to control their disease. On initial presentation, it can sometimes be difficult to distinguish between these 2 diseases, as both present with muscle pain, weakness, and elevated serum creatine kinase (CK) levels. The goal of this study was to determine whether patients with severe self-limited statin-related myopathy also make anti-HMGCR autoantibodies. Methods: We screened 101 subjects with severe self-limited cerivastatin-related myopathy for anti-HMGCR autoantibodies. Results: No patient with severe self-limited cerivastatin-related myopathy had anti-HMGCR autoantibodies. Conclusion: Anti-HMGCR autoantibody testing can be used to help differentiate whether a patient has self-limited myopathy due to cerivastatin or autoimmune statin-associated myopathy; these findings may apply to other statins as well. Muscle Nerve 54: 142–144, 2016.