[Clinical analysis of 160 cases of statin-induced myopathy]

To analyze the clinical features of statin-induced myopathy.

The statin-induced myopathy case reported as adverse drug reaction (ADR) to the Beijing Center for ADR Monitoring during January 2007 to December 2012 was summarized, patients were divided to myopathy group and rhabdomyolysis group, according to the absence or presence of rhabdomylysis. The clinical characteristics, medication history and outcome were compared between the two groups.

A total of 160 statin-induced myopathy cases (54 in rhabdomyolysis group (33.8%) and 106 cases in myopathy group (66.3%)) were collected from the database (mean age: (64.22 ± 13.55) years old, 51.2% male, n = 82). The ADR occurred immediately after the first medication and up to 4 years after medication. Observed clinical features were myalgia, myositis, asymptommatic creatine kinase (CK) elevation or rhabdomyolysis. The average age were (68.54 ± 15.41) years old in rhabdomylysis group and (62.02 ± 12.41) years old in myopathy group (P = 0.004). There was no gender difference between the rhabdomylysis group and myopathy group (P = 0.406) . Twenty-four cases (44.4%) in rhabdomyolysis group and 26 cases (16.5%) in myopathy group were treated with high dose statin (P < 0.001). Percent of simvastatin treatment was significantly higher in rhabdomyolysis group (70.4% (38/54) ) than in myopathy group (32.1% (34/106), P < 0.001). Spearman correlation analysis showed that age, high-dose statin treatment and simvastatin use were all positively correlated with rhabdomylysis (P < 0.001), and the correlation coefficients (r value) were 0.305, 0.290 and 0.364, respectively. Four patients (aged from 71 to 85 years) died because of ADR and all 4 cases received high-dose statin treatment, 3 of them suffered from complex combined diseases, acute disease progression and complex multiple drug use history.

Severe statin-induced myopathy, like rhabdomyolysis, is more likely to occur in old patients, in patients taking high-dose statin, especially simvastatin.