Reliability of calculated low-density lipoprotein cholesterol

Jeffrey W. Meeusen, Christine L. Snozek, Nikola A. Baumann, Allan S. Jaffe, Amy K. Saenger

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Aggressive low-density lipoprotein cholesterol (LDL-C)-lowering strategies are recommended for prevention of cardiovascular events in high-risk populations. Guidelines recommend a 30% to 50% reduction in at-risk patients even when LDL-C concentrations are between 70 and 130 mg/dl (1.8 to 3.4 mmol/L). However, calculation of LDL-C by the Friedewald equation is the primary laboratory method for routine LDL-C measurement. We compared the accuracy and reproducibility of calculated LDL-C <130 mg/dl (3.4 mmol/L) to LDL-C measured by β quantification (considered the gold standard method) in 15,917 patients with fasting triglyceride concentrations <400 mg/dl (4.5 mmol/L). Both variation and bias of calculated LDL-C increased at lower values of measured LDL-C. The 95% confidence intervals for a calculated LDL-C of 70 mg/dl (1.8 mmol/L) and 30 mg/dl (0.8 mmol/L) were 60 to 86 mg/dl (1.6 to 2.2 mmol/L) and 24 to 60 mg/dl (0.6 to 1.6 mmol/L), respectively. Previous recommendations have emphasized the requirement for a fasting sample with triglycerides <400 mg/dl (4.5 mmol/L) to calculate LDL-C by the Friedewald equation. However, no recommendations have addressed the appropriate lower reportable limit for calculated LDL-C. In conclusion, calculated LDL-C <30 mg/dl (0.8 mmol/L) should not be reported because of significant deviation from the gold standard measured LDL-C results, and caution is advised when using calculated LDL-CF values <70 mg/dl (1.8 mmol/L) to make treatment decisions.

Original languageEnglish (US)
Pages (from-to)538-540
Number of pages3
JournalAmerican Journal of Cardiology
Volume116
Issue number4
DOIs
StatePublished - Aug 15 2015

Bibliographical note

Funding Information:
This work was not supported by any grants, contracts, or other forms of financial support or any relations with industry. The authors have no conflicts of interest to disclose.

Publisher Copyright:
© 2015 Elsevier Inc. All rights reserved.

Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.

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