Effects of ezetimibe, simvastatin and ezetimibe/simvastatin on correlations between apolipoprotein B, LDL cholesterol and non-HDL cholesterol in patients with primary hypercholesterolemia.

BACKGROUND/SYNOPSIS: Apolipoprotein (apo) B is highly predictive of coronary risk, especially in patients with high triglycerides (TG). This post hoc analysis evaluated the effects of lipid-lowering therapy on correlations between apoB and low-density lipoprotein cholesterol (apoB:LDL-C) and non-high-density lipoprotein cholesterol (apoB:non-HDL-C) in patients with TG< and ≥ 200 mg/dL.

METHODS: This analysis used data from 3 randomized clinical trials in patients with primary hypercholesterolemia receiving placebo, ezetimibe (EZE), simvastatin (SIMVA) or EZE/SIMVA for 12 weeks. Simple linear regression analyses predicted LDL-C and non-HDL-C levels corresponding to apoB values (80 mg/dL) at baseline and Week 12.

RESULTS: ApoB correlated with LDL-C (r ≥ 0.76) and non-HDL-C (r ≥ 0.86) at baseline. The correlations were strengthened with SIMVA and EZE/SIMVA at Week 12 (r ≥ 0.88 for LDL-C and r ≥ 0.94 for non-HDL-C). The predicted LDL-C and non-HDL-C values were lower following treatment with SIMVA or EZE/SIMVA than for placebo and EZE. For SIMVA and EZE/SIMVA, the predicted LDL-C and non-HDL-C values were closer to more aggressive LDL-C and non-HDL-C levels (i.e., 70 and 100 mg/dL, respectively). The apoB:LDL-C and apoB:non-HDL-C correlations were weaker and the predicted LDL-C values were generally lower in high TG patients than in low TG patients both at baseline and Week 12. In contrast, the predicted non-HDL-C values were generally higher in high versus low TG patients at baseline but less so at Week 12.

CONCLUSION: After treatment with EZE, SIMVA, or EZE/SIMVA, a given apoB value corresponds to lower LDL-C and non-HDL-C levels than those obtained from untreated patients.