Effect of the Magnitude of Lipid Lowering on Risk of Elevated Liver Enzymes, Rhabdomyolysis, and Cancer. Insights From Large Randomized Statin Trials
We sought to assess the relationship between the magnitude of low-density lipoprotein cholesterol (LDL-C) lowering and rates of elevated liver enzymes, rhabdomyolysis, and cancer. Although it is often assumed that statin-associated adverse events are proportional to LDL-C reduction, that assumption has not been validated. Adverse events reported in large prospective randomized statin trials were evaluated. The relationship between LDL-C reduction and rates of elevated liver enzymes, rhabdomyolysis, and cancer per 100,000 person-years was assessed using weighted univariate regression. In 23 statin treatment arms with 309,506 person-years of follow-up, there was no significant relationship between percent LDL-C lowering and rates of elevated liver enzymes (R2 <0.001, p = 0.91) or rhabdomyolysis (R2 = 0.05, p = 0.16). Similar results were obtained when absolute LDL-C reduction or achieved LDL-C levels were considered. In contrast, for any 10% LDL-C reduction, rates of elevated liver enzymes increased significantly with higher statin doses. Additional analyses demonstrated a significant inverse association between cancer incidence and achieved LDL-C levels (R2 = 0.43, p = 0.009), whereas no such association was demonstrated with percent LDL-C reduction (R2 = 0.09, p = 0.92) or absolute LDL-C reduction (R2 = 0.05, p = 0.23). Risk of statin-associated elevated liver enzymes or rhabdomyolysis is not related to the magnitude of LDL-C lowering. However, the risk of cancer is significantly associated with lower achieved LDL-C levels. These findings suggest that drug- and dose-specific effects are more important determinants of liver and muscle toxicity than magnitude of LDL-C lowering. Furthermore, the cardiovascular benefits of low achieved levels of LDL-C may in part be offset by an increased risk of cancer.