Statin-induced myopathy is rare.

INTRODUCTION: Statin-induced myopathy (SIM) is a rare but serious complication of statin therapy. Immune-mediated necrotising myopathy linked to anti-3-hydroxy-3-methylglutaryl (HMG)-CoA reductase (anti-HMGCR) antibodies requires timely recognition. This study examined the occurrence and documentation of SIM and the use of antibody testing in a regional cohort. METHODS: This was a register-based study using data from regional registries and medical records (2020-2024). Patients with creatine kinase (CK) > 10 × the upper limit of normal while receiving statin therapy were identified, characterised and compared, with a special focus on anti-HMGCR antibody testing and documentation of statin intolerance. RESULTS: Among 1,003 patients, 32 (3.2%) were considered to have SIM. These patients had a higher median CK than other patients (7,800 versus 3,783 U/l; p less-than 0.001). High-intensity therapy was more frequent in SIM (72% versus 52%; p = 0.02), with a prevalence ratio of 2.34 (95% CI: 1.09-5.00). Anti-HMGCR testing was performed in 56% of SIM cases; antibody-positive patients had lower CK and higher eGFR. Documentation of statin intolerance in the electronic record CAVE field (adverse drug reaction) was present in only 59%. CONCLUSIONS: Severe SIM is uncommon (4.3 cases/100,000 patient-years), but documentation and diagnostic testing are inconsistent. Systematic recording and broader antibody testing may improve patient safety. FUNDING: None. TRIAL REGISTRATION: Not relevant.