特発性炎症性筋症：稀な病気だが、スタチンと関連

オーストラリアの住民ベース(South Australian Myositis Database )症例対照研究

組織所見確認のIdiopathic inflammatory myosis(IIM)：特発性炎症性筋症

診断時スタチン暴露 68/221(30.8%) vs マッチ化対照 142/662(21.5%) p=0.005

ほぼ２倍の尤度 補正オッズ比 1.79 95% 信頼区間 ;1.23 - 2.60 p=0.001

壊死性筋炎(necrotizing myositis)を除外した場合でも同様の結果


Association of Statin Exposure With Histologically Confirmed Idiopathic Inflammatory Myositis in an Australian Population
JAMA Intern Med. Published online July 30, 2018. doi:10.1001/jamainternmed.2018.2859
https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2687990

スタチン関連のmyalgia(筋痛)を含む筋骨格系副作用は稀で、発生頻度 １万人年対 0.4
しかもスタチン中止すれば回復する事が多い
しかし、炎症性筋炎を生じる事例報告、稀で臨床的にheterogenosu、自己免疫性筋疾患とも考える

序文

Idiopathic inflammatory myositis commonly appears as painless, proximal limb girdle weakness with multisystem involvement. Creatinine kinase levels are commonly elevated, and treatment includes high-dose corticosteroids and other forms of immunosuppressive therapies. There are a number of distinct subsets of IIM that are distinguished by clinical features, characteristic histopathologic features, and the presence of myositis-specific autoantibodies. Subsets of IIM include polymyositis, dermatomyositis, inclusion body myositis, and immune-mediated necrotizing myositis. The latter, immune-mediated necrotizing myopathy, has been reported in association with a number of factors, including viral infections, connective-tissue disorders, or exposure to a statin medication. More recently, statin-associated autoimmune myopathy has been recognized as a distinct entity, with the presence of a specific autoantibody against HMG-CoA reductase

ステロイド治療必要で、筋炎特異的抗体にて鑑別
HMG-CoAリダクターゼに対する特異抗体を有する別のentityの存在も認識されている