Background: Published studies regarding statin-associated myopathy may describe more dramatic patient presentations, potentially leading to inaccurate characterization of the condition. Furthermore, long-term outcomes and responses to statin rechallenge in patients with statin-associated myopathy are largely unknown.
Methods: The University of Wisconsin Hospital and Clinics Medical Informatics Department identified 437 patients with International Classification of Diseases, Ninth Revision codes potentially representing cases of statin-associated myopathy from more than 13 years of inpatient and outpatient data; 45 of these individuals were diagnosed as having statin-associated myopathy. Using a standardized form, 2 researchers abstracted all the case records to define the clinical course of statin-induced myopathy.
Results: The mean (SD) duration of statin therapy before symptom onset was 6.3 (9.8) months. Resolution of muscle pain occurred a mean (SD) of 2.3 (3.0) months after discontinuation of statin therapy. Six patients (13%) were hospitalized for the management of rhabdomyolysis; 2 had reversible renal dysfunction, and 1 with preexisting renal insufficiency subsequently began lifelong dialysis. Hospitalized patients developed myopathy more quickly after initiating statin therapy (1.3 vs 7.1 months; P = .048) and were more likely to be taking concomitant medications known to increase the risk of statin-associated myopathy (P = .03). Thirty-seven patients received another statin after an episode of statin-associated myopathy; 21 (57%) reported recurrent muscle pain, whereas 16 (43%) tolerated other statins without recurrent symptoms.
Conclusions: Patients with statin-associated myopathy experienced full resolution of muscle pain on cessation of statin therapy. Although no deaths occurred, 13% of the patients required hospitalization for rhabdomyolysis. Recurrent muscle pain was common on statin rechallenge.