Mike Rosenbloom Laboratory for Cardiovascular Research, McGill University Health Centre, Royal Victoria Hospital, Room H7.22, 687 Pine Avenue West, Montreal, Québec, Canada H3A 1A1.
J Clin Lipidol. 2013 Nov-Dec;7(6):626-31. doi: 10.1016/j.jacl.2013.08.004. Epub 2013 Aug 31.
Patients with increased numbers of cholesterol-depleted apolipoprotein B (apoB) particles frequently have multiple other abnormalities, which might confound the comparison of apoB and non-high-density-lipoprotein-cholesterol (non-HDL-C) as markers of cardiovascular risk.
We wanted to determine whether the superiority of apoB over non-HDL-C as a marker of cardiovascular risk in the INTERHEART study is due to such variables that act as confounders of the primary comparison.
To test for confounding, cases and controls were first separated into 3 groups on the basis of the percentile levels within the study of non-HDL-C and apoB with discordance defined as a difference of 5 percentile points. Logistic regression was used to compute odds ratio of myocardial infarction (as an outcome) for different categories, assuming concordance as reference adjusted for other confounders.
Plasma triglyceride and non-HDL-C levels were highest in the discordant group with lowest risk and lowest in the discordant group with highest risk, whereas apoB was highest in the discordant group with the highest risk and lowest in the discordant group with the lowest group. Moreover, no significant change was found in the odds ratio for either discordant group when adjusted for the effect of any of the variables examined, evidence that none confounded the primary comparison.
Factors such as hypertriglyceridemia do not confound the comparison of apoB and non-HDL-C, further evidence that apoB is superior to non-HDL-C as a marker of the importance of the apoB atherogenic lipoproteins in cardiovascular risk.
载有大量胆固醇 depleted apolipoprotein B (apoB) 颗粒的患者通常存在多种其他异常，这可能会混淆 apoB 和非高密度脂蛋白胆固醇 (non-HDL-C) 作为心血管风险标志物的比较。
我们想确定在 INTERHEART 研究中，apoB 作为心血管风险标志物优于非 HDL-C 是否归因于作为混杂因素的这些变量。
为了检验混杂因素，首先根据非 HDL-C 和 apoB 在研究中的百分位水平将病例和对照分为 3 组，不一致定义为差异 5 个百分位点。采用 logistic 回归计算不同类别心肌梗死（作为结果）的优势比，假设一致性为参考，根据其他混杂因素进行调整。
在 discordant 组中，血浆甘油三酯和非 HDL-C 水平最高，风险最低，在 discordant 组中，风险最高，apoB 水平最高，风险最高，apoB 水平最低。此外，当调整任何检查变量的影响时，两个 discordant 组的比值比均无显著变化，这表明没有混杂因素影响主要比较。
诸如高甘油三酯血症等因素不会混淆 apoB 和非 HDL-C 的比较，进一步证明 apoB 作为 apoB 致动脉粥样硬化脂蛋白在心血管风险中的重要性的标志物优于非 HDL-C。
