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‐PLA(2)]) was assessed. METHODS AND RESULTS: Treatment effects on low‐ and high‐density lipoprotein particle number (by NMR) and Lp‐PLA(2) (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‐PLA(2) 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‐PLA(2) concentration were modest. CONCLUSIONS: In diabetic patients with dyslipidemia, switching from statins to combination ES10/20 therapy generally improved lipoprotein subclass profile and Lp‐PLA(2) 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.