Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (V.S., R.Q., R.S.B., S.R.J., S.S.M.).
Department of Epidemiology (J.P., A.G., M.L., E.G.).
Circulation. 2018 Jan 2;137(1):10-19. doi: 10.1161/CIRCULATIONAHA.117.030677. Epub 2017 Oct 16.
Recent recommendations favoring nonfasting lipid assessment may affect low-density lipoprotein cholesterol (LDL-C) estimation. The novel method of LDL-C estimation (LDL-C) uses a flexible approach to derive patient-specific ratios of triglycerides to very low-density lipoprotein cholesterol. This adaptability may confer an accuracy advantage in nonfasting patients over the fixed approach of the classic Friedewald method (LDL-C).
We used a US cross-sectional sample of 1 545 634 patients (959 153 fasting ≥10-12 hours; 586 481 nonfasting) from the second harvest of the Very Large Database of Lipids study to assess for the first time the impact of fasting status on novel LDL-C accuracy. Rapid ultracentrifugation was used to directly measure LDL-C content (LDL-C). Accuracy was defined as the percentage of LDL-C falling within an estimated LDL-C (LDL-C or LDL-C) category by clinical cut points. For low estimated LDL-C (<70 mg/dL), we evaluated accuracy by triglyceride levels. The magnitude of absolute and percent differences between LDL-C and estimated LDL-C (LDL-C or LDL-C) was stratified by LDL-C and triglyceride categories.
In both fasting and nonfasting samples, accuracy was higher with the novel method across all clinical LDL-C categories (range, 87%-94%) compared with the Friedewald estimation (range, 71%-93%; ≤0.001). With LDL-C <70 mg/dL, nonfasting LDL-C accuracy (92%) was superior to LDL-C accuracy (71%; <0.001). In this LDL-C range, 19% of fasting and 30% of nonfasting patients had differences ≥10 mg/dL between LDL-C and LDL-C, whereas only 2% and 3% of patients, respectively, had similar differences with novel estimation. Accuracy of LDL-C <70 mg/dL further decreased as triglycerides increased, particularly for Friedewald estimation (range, 37%-96%) versus the novel method (range, 82%-94%). With triglycerides of 200 to 399 mg/dL in nonfasting patients, LDL-C <70 mg/dL accuracy (82%) was superior to LDL-C (37%; <0.001). In this triglyceride range, 73% of fasting and 81% of nonfasting patients had ≥10 mg/dL differences between LDL-C and LDL-C compared with 25% and 20% of patients, respectively, with LDL-C.
Novel adaptable LDL-C estimation performs better in nonfasting samples than the fixed Friedewald estimation, with a particular accuracy advantage in settings of low LDL-C and high triglycerides. In addition to stimulating further study, these results may have immediate relevance for guideline committees, laboratory leadership, clinicians, and patients.
URL: https://www.clinicaltrials.gov. Unique identifier: NCT01698489.
最近的推荐意见倾向于非空腹血脂评估，这可能会影响到低密度脂蛋白胆固醇（LDL-C）的估计值。LDL-C 的新估计方法（LDL-C）采用了一种灵活的方法来推导患者特定的甘油三酯与极低密度脂蛋白胆固醇的比值。与经典 Friedewald 方法（LDL-C）的固定方法相比，这种适应性可能会在非空腹患者中提供更准确的 LDL-C 估计值。
我们使用了来自第二波 Very Large Database of Lipids 研究的 1545634 名美国横断面患者（959153 名禁食≥10-12 小时；586481 名非禁食）的样本，首次评估了空腹状态对新型 LDL-C 准确性的影响。快速超速离心法直接测量 LDL-C 含量（LDL-C）。准确性定义为根据临床切点，落在估计 LDL-C（LDL-C 或 LDL-C）类别内的 LDL-C 百分比。对于估计 LDL-C 较低（<70mg/dL）的患者，我们通过甘油三酯水平评估准确性。根据 LDL-C 和甘油三酯类别，对 LDL-C 与估计 LDL-C（LDL-C 或 LDL-C）之间的绝对和百分比差异的大小进行分层。
在禁食和非禁食样本中，与 Friedewald 估计值（范围 71%-93%）相比，新型方法在所有临床 LDL-C 类别中（范围 87%-94%）的准确性更高（均<0.001）。对于 LDL-C<70mg/dL，非禁食 LDL-C 准确性（92%）优于 LDL-C 准确性（71%；<0.001）。在这个 LDL-C 范围内，19%的禁食患者和 30%的非禁食患者的 LDL-C 和 LDL-C 之间的差异≥10mg/dL，而分别只有 2%和 3%的患者具有类似的差异。随着甘油三酯的增加，LDL-C<70mg/dL 的准确性进一步降低，尤其是 Friedewald 估计值（范围 37%-96%）与新型方法（范围 82%-94%）相比。在非禁食患者的甘油三酯为 200-399mg/dL 的情况下，LDL-C<70mg/dL 的准确性（82%）优于 LDL-C（37%；<0.001）。在这个甘油三酯范围内，与 LDL-C 相比，73%的禁食患者和 81%的非禁食患者的 LDL-C 和 LDL-C 之间的差异≥10mg/dL，而分别只有 25%和 20%的患者具有 LDL-C。
新型适应性 LDL-C 估计方法在非禁食样本中的表现优于固定的 Friedewald 估计方法，尤其是在 LDL-C 较低和甘油三酯较高的情况下具有更高的准确性。除了激发进一步的研究外，这些结果可能对指南委员会、实验室领导层、临床医生和患者具有直接的意义。
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