Effect of Switching From Statin Monotherapy to Ezetimibe/Simvastatin Combination Therapy Compared With Other Intensified Lipid-Lowering Strategies on Lipoprotein Subclasses in Diabetic Patients With Symptomatic Cardiovascular Disease.

BACKGROUND Patients with diabetes mellitus and cardiovascular disease may not achieve adequate low-density lipoprotein cholesterol (LDL-C) lowering on statin monotherapy, attributed partly to atherogenic dyslipidemia. More intensive LDL-C-lowering therapy can be considered for these patients. A previous randomized, controlled study demonstrated greater LDL-C lowering in diabetic patients with symptomatic cardiovascular disease who switched from simvastatin 20 mg (S20) or atorvastatin 10 mg (A10) to combination ezetimibe/simvastatin 10/20 mg (ES10/20) therapy, compared with statin dose-doubling (to S40 or A20) or switching to rosuvastatin 10 mg (R10). The effect of these regimens on novel biomarkers of atherogenic dyslipidemia (low- and high-density lipoprotein particle number and lipoprotein-associated phospholipase A2 [Lp-PLA2]) was assessed. METHODS AND RESULTS Treatment effects on low- and high-density lipoprotein particle number (by NMR) and Lp-PLA2 (by ELISA) were evaluated using plasma samples available from 358 subjects in the study. Switching to ES10/20 reduced low-density lipoprotein-particle number numerically more than did statin dose-doubling and was comparable with R10 (-133.3, -94.4, and -56.3 nmol/L, respectively; P>0.05). Increases in high-density lipoprotein particle number were significantly greater with switches to ES10/20 versus statin dose-doubling (1.5 and -0.5 μmol/L; P<0.05) and comparable with R10 (0.7 μmol/L; P>0.05). Percentages of patients attaining low-density lipoprotein particle number levels <990 nmol/L were 62.4% for ES10/20, 54.1% for statin dose-doubling, and 57.0% for R10. Switching to ES10/20 reduced Lp-PLA2 activity significantly more than did statin dose-doubling (-28.0 versus -3.8 nmol/min per mL, P<0.05) and was comparable with R10 (-28.0 versus -18.6 nmol/min per mL; P>0.05); effects on Lp-PLA2 concentration were modest. CONCLUSIONS In diabetic patients with dyslipidemia, switching from statins to combination ES10/20 therapy generally improved lipoprotein subclass profile and Lp-PLA2 activity more than did statin dose-doubling and was comparable with R10, consistent with its lipid effects. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00862251.