Abstract
Statin-associated muscle symptoms are frequently reported and often lead to discontinuation of statin therapy with an increased risk of cardiovascular events. In vitro studies suggest that statin-mediated inhibition of the mevalonate pathway leads to muscle cell toxicity. We aimed to determine the relationship between mevalonate, LDL-cholesterol, and atorvastatin metabolites in patients with coronary heart disease and self-perceived muscle side effects. Furthermore, we assessed the correlation between mevalonate in blood and muscle and the relationship to statin intolerance due to muscle symptoms. We used blood plasma from a randomized crossover trial (n = 70) and muscle biopsies and plasma from a subgroup in a subsequent open intervention study (n = 26). Both studies tested atorvastatin 40 mg/day. Seven patients did not tolerate ≥3 statins throughout the follow-up and were classified as statin-intolerant. Mevalonate in blood plasma decreased during atorvastatin treatment (median difference -38%, range -77% to 43%, p < 0.001), whereas mevalonate in muscle tissue was not lowered (0.05%, range -47% to 145%). Mevalonate correlated poorly with LDL-cholesterol and atorvastatin metabolites (Spearman's rho -0.28 to 0.10). The statin-intolerant patients had a smaller reduction in circulating mevalonate compared with the tolerant patients; median difference -8.1 (-22 to 3.5) nmol/L versus -25 (-93 to 12) nmol/L, p = 0.028. A similar observation was made for LDL-cholesterol. Cutoffs based on these biomarkers classified >50% correctly as tolerant. Inhibition of the mevalonate pathway does not appear to be the mechanism underlying statin intolerance in the present study. Further studies of mevalonate as a biomarker for statin tolerance are needed to clarify the potential.