Low myopathy rates associated with statins as monotherapy or combination therapy with interacting drugs in a group model health maintenance organization.Pharmacotherapy. 2005 Mar; 25(3):345-51.P
Because the risk for myopathy increases when 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) are used with other agents known to inhibit cytochrome P450 3A4 in patients with dyslipidemia, we sought to quantify this risk in a diverse, real-world sample of patients receiving statin therapy.
Retrospective chart review.
Kaiser Permanente Colorado (KPCO), a group model health maintenance organization with approximately 360,000 members.
Four hundred sixty-eight patients who were identified as having a diagnosis of myopathy over a 4-year period using KPCO computerized data systems.
MEASUREMENTS AND MAIN RESULTS
Medical records were reviewed to confirm myopathy cases associated with statin therapy. Of the 468 patients, 61 had received statin therapy before their diagnosis, and 41 (67%) of these patients had confirmed myopathy (documented creatine kinase level>or=1000 IU/L). The prevalence of myopathy was 0.12% with statin monotherapy and 0.22% with statins in combination with interacting drugs. Only 17 of the 41 (41%) patients had confirmed myopathy with no other plausible clinical explanation, such as a muscle injury. Increased risk of myopathy associated with statin therapy in combination with interacting drugs approached statistical significance (p=0.052) but was of minimal clinical significance.
The prevalence of confirmed myopathy in patients receiving statin therapy is low (<1%). Combining statin therapy with interacting drugs (e.g., fibrates) was not associated with a clinically important increase in the prevalence of myopathy. The risk of developing myopathy during statin therapy is outweighed by the benefits derived from the therapeutic effects of the therapy.