| Statin-associated Autoimmune Myopathy | |
|---|---|
| Other names | Anti-HmG Coenzyme A Reductase Myopathy, Immune-mediated necrotizing myopathy associated with statins, Statin-associated immune-mediated myopathy, Statin-induced autoimmune myositis, Statin-induced necrotizing autoimmune myopathy |
| Specialty | Rheumatology |
| Symptoms | Muscle weakness |
| Treatment | Corticosteroids, immunosuppressive medications, withdrawal of the implicated statin |
| Frequency | Rare |
Statin-associated autoimmune myopathy (SAAM), also known as anti-HMGCR myopathy, is a very rare form of muscle damage caused by the immune system in people who take statin medications.[1] However, there are cases of SAAM in patients who have not taken statin medication, and this can be explained by the exposure to natural sources of statin such as red yeast rice, which is statin rich. This theory is supported by the higher prevalence of statin-naive SAAM patients in Asian cohorts, who have statin-rich diets.[2]
The exact cause is unclear. A combination of consistent findings on physical examination, the presence of anti HMG-CoA reductase antibodies in a person with myopathy, evidence of muscle breakdown, and muscle biopsy diagnose SAAM.[3]
Treatment involves stopping the associated statin medication and taking medication to suppress the immune system.
SAAM is estimated to occur in 2-3 people out of every 100,000 statin-treated individuals. It appears to be more common in people over the age of 50.[3]