Prevalence of statin-induced rhabdomyolysis in Asian populations

Purpose: The incidence of simvastatin-induced rhabdomyolysis occurrences is high at FDA recommended dosing guidelines in Asian populations.  This study aims to evaluate the prevalence of statin-induced rhabdomyolysis in Asians in order to 1) review the safety profile of statin use and 2) compare dose-related rhabdomyolysis in both mono- and combination statin therapy. 

Methods: A total of 24, 333 patients prescribed with any statins were reviewed via medical record from 2008-2011 in a general hospital in Singapore. These hospitalized patients with clinically diagnosed rhabdomyolysis were identified through ICD-9 codes, excluding those with post-operational rhabdomyolysis, peak creatine kinase (CK) < 1000 IU/L or incomplete clinical records. Data collection parameters include patient demographics, pertinent labs (peak CK levels, lipids, liver and renal panels) and clinical symptoms of myopathy. 

Results: Ninety two patients (0.38%) were hospitalized for rhabdomyolysis at the FDA recommended simvastatin dosages (median dosage = 20mg). Four patients underwent recurrent rhabdomyolysis hospitalizations prior to their statins being discontinued (average dose = 25mg). Eighteen cases (0.07%) reported severe rhabdomyolysis (CK > 10,000 IU/L) with a median peak CK of 30,765 IU/L and median simvastatin dose of 20mg. The remaining cases (10,000 ≤ CK < 1000) had a median peak CK of 2385 IU/L and median simvastatin dose of 10mg. The average statin exposure duration before the onset of rhabdomyolysis was 625.7 ± 625.4 days. Eleven patients (0.05%) expired during hospitalization due to the combinatorial effect of rhabdomyolysis, infection and/or acute myocardial infarction. 

Conclusion: Our finding suggests the dosage of statins should be lower compared to that recommended by the US to avoid serious adverse events related to rhabdomyolysis. Given the potential pharmacokinetic and pharmacodynamic sensitivity of Asian patients to higher statin related adverse events, it may warrant a more judicious approach to statin titration in these patients.