Friedwald’s Calculation; Is It Reliable in Estimating Risk of Coronary Heart Disease?
Friedwald’s Calculation; Is It Reliable in Estimating Risk of Coronary Heart Disease?
Keywords:
Friedwald’s calculation, direct method, non-HDL-CAbstract
Background and Objectives: Accurate determination of LDL-C is important for the identification and management of patients at risk of CHD. The limitations of the Friedwald’s equation led to the expensive direct homogenous assays and an interest in non-HDL-C as markers of risk of CHD, particularly in patients with elevated triglycerides. There are conflicting reports on whether the Friedwald’s underestimates LDL-C in comparison to direct, so this study compared the two methods in 800 out patients. Also, comparison of CHD risk detection was done by LDL-C direct, LDL-C calculated and non-HDL-C. Methods and Results: LDL-C by direct method was significantly higher than calculated (mean difference 7.75 mg/dl) and the difference was progressively higher across all categories of TG and TC. The Friedwald’s calculation underestimated 570 (71.25%) compared to direct method. Using NCEP risk categorization for LDL-C (<130mg/dl low risk) and non-HDL-C risk categorization of 30mg/dl above that of LDL-C, those at higher risk of CHD numbered 320 (40%) by the direct, 270(33.75%) by non-HDL-C and 220(27.5%) by the calculated method. Overall, 660 (82.5%) out of 800 were similarly classified by all three methods. Conclusion: Although the Friedwald’s calculation performs reasonably well, it underestimates LDL-C compared to direct method. It misses identifying a significant number of patients at risk of CHD by direct LDL-C and by non-HDL-C. [Biswas S NJIRM 2017; 8(4):27-31]
References
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8. Virani SS. Non-HDL Cholesterol as a Metric of Good Quality of Care. Tex Heart Inst J. 2011;38:160–2.
9. Bansal E, Kaur N. Does friedewald formula underestimate the risk of ischemic heart disease? Indian J Clin Biochem. 2014;29:496–500.
10. Sahu S, Chawla R, Uppal B. Comparison of two methods of estimation of low density lipoprotein cholesterol, the direct versus friedewald estimation. Indian J Clin Biochem. 2005;20:54–61.
11. Meiattini F, Prencipe L, Bardelli F, Giannini G, Tarli P. The 4-hydroxybenzoate/4-aminophenazone chromogenic system used in the enzymic determination of serum cholesterol. Clin Chem. 1978;24:2161–2165.
12. Fossati P, Prencipe L. Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide. Clin Chem. 1982;28:2077–80.
13. Nauck M, Graziani MS, Bruton D, Cobbaert C, Cole TG, Lefevre F, et al. Analytical and clinical performance of a detergent-based homogeneous LDL-cholesterol assay: a multicenter evaluation. Clin Chem. 2000;46:506–14.
14. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18:499–502.
15. Nauck M, Warnick GR, Rifai N. Methods for Measurement of LDL-Cholesterol: A Critical Assessment of Direct Measurement by Homogeneous Assays versus Calculation. Clin Chem. 2002;48:236–54.
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17. Tighe DA, Ockene IS, Reed G, Nicolosi R. Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation. Clin Chim Acta. 2006;365:236–42.
18. Evans SR, Fichtenbaum CJ, Aberg JA. Comparison of Direct and Indirect Measurement of LDL-C in HIV-Infected Individuals: ACTG 5087. HIV Clin Trials. 2007;8:45–52.
19. Baruch L, Agarwal S, Gupta B, Haynos A, Johnson S, Kelly-Johnson K, et al. Is directly measured low-density lipoprotein clinically equivalent to
calculated low-density lipoprotein? J Clin Lipidol. 2010;4:259–64.
20. Jun KR, Park HI, Chun S, Park H, Min WK. Effects of total cholesterol and triglyceride on the percentage difference between the low-density lipoprotein cholesterol concentration measured directly and calculated using the Friedewald formula. Clin Chem Lab Med. 2008;46:371-5
21. Mora S, Rifai N, Buring JE, Ridker PM. Comparison of LDL Cholesterol Concentrations by Friedewald Calculation and Direct Measurement in Relation to Cardiovascular Events in 27 331 Women. Clin Chem. 2009;55:888–94.
22. Anandaraja S, Narang R, Godeswar R, Laksmy R, Talwar KK. Low-density lipoprotein cholesterol estimation by a new formula in Indian population. Int J Cardiol. 2005;102:117–20.
23. Boshtam M, Ramezani MA, Naderi G, Sarrafzadegan N. Is Friedewald formula a good estimation for low density lipoprotein level in Iranian population? J Res Med Sci. 2012;17:519–22.
24. Baruch L, Chiong VJ, Agarwal S, Gupta B. Discordance of Non-HDL and Directly Measured LDL Cholesterol: Which Lipid Measure is Preferred When Calculated LDL Is Inaccurate? Cholesterol. 2013;2013:502948.doi:10.1155/2013/502948
25. Bittner V. Non-HDL Cholesterol- measurement, interpretation, and significance. Adv Stud Med. 2007;7:8–11.
26. Cui Y, Blumenthal RS, Flaws JA, Whiteman MK, Langenberg P, Bachorik PS, et al. Non-high-density lipoprotein cholesterol level as a predictor of cardiovascular disease mortality. Arch Intern Med. 2001;161:1413–9.
2. Anderson KM, Castelli WP, Levy D. Cholesterol and Mortality. 30 Years of Follow-up From the Framingham Study. J Am Med Assoc. 1987;257:2176–80.
3. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). J Am Med Assoc. 2001;285:2486–97.
4. Miller WG, Waymack PP, Anderson FP, Ethridge SF, Jayne EC. Performance of four homogeneous direct methods for LDL-cholesterol. Clin Chem. 2002;48:489–98.
5. Bachorik PS, Ross JW. For the National Cholesterol Education Program Working Group on Lipoprotein Measurements. The National Cholesterol Education Program recommendations for measurement of low-density lipoprotein cholesterol: executive summary. Clin Chem. 1995;41:1414–20.
6. McNamara JR, Cohn JS, Wilson PW, Schaefer EJ. Calculated values for low-density lipoprotein cholesterol in the assessment of lipid abnormalities and coronary disease risk. Clin Chem. 1990;36:36–42.
7. Rifai N, Iannotti E, DeAngelis K, Law T. Analytical and clinical performance of a homogeneous enzymatic LDL-cholesterol assay compared with the ultracentrifugation-dextran sulfate-Mg2+ method. Clin Chem. 1998;44:1242–50.
8. Virani SS. Non-HDL Cholesterol as a Metric of Good Quality of Care. Tex Heart Inst J. 2011;38:160–2.
9. Bansal E, Kaur N. Does friedewald formula underestimate the risk of ischemic heart disease? Indian J Clin Biochem. 2014;29:496–500.
10. Sahu S, Chawla R, Uppal B. Comparison of two methods of estimation of low density lipoprotein cholesterol, the direct versus friedewald estimation. Indian J Clin Biochem. 2005;20:54–61.
11. Meiattini F, Prencipe L, Bardelli F, Giannini G, Tarli P. The 4-hydroxybenzoate/4-aminophenazone chromogenic system used in the enzymic determination of serum cholesterol. Clin Chem. 1978;24:2161–2165.
12. Fossati P, Prencipe L. Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide. Clin Chem. 1982;28:2077–80.
13. Nauck M, Graziani MS, Bruton D, Cobbaert C, Cole TG, Lefevre F, et al. Analytical and clinical performance of a detergent-based homogeneous LDL-cholesterol assay: a multicenter evaluation. Clin Chem. 2000;46:506–14.
14. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18:499–502.
15. Nauck M, Warnick GR, Rifai N. Methods for Measurement of LDL-Cholesterol: A Critical Assessment of Direct Measurement by Homogeneous Assays versus Calculation. Clin Chem. 2002;48:236–54.
16. Anwar M, Khan DA, Khan FA. Comparison of friedewald formula and modified friedewald formula with direct homogeneous assay for low density lipoprotein cholesterol estimation. J Coll Physicians Surg Pak. 2014;24:8–12.
17. Tighe DA, Ockene IS, Reed G, Nicolosi R. Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation. Clin Chim Acta. 2006;365:236–42.
18. Evans SR, Fichtenbaum CJ, Aberg JA. Comparison of Direct and Indirect Measurement of LDL-C in HIV-Infected Individuals: ACTG 5087. HIV Clin Trials. 2007;8:45–52.
19. Baruch L, Agarwal S, Gupta B, Haynos A, Johnson S, Kelly-Johnson K, et al. Is directly measured low-density lipoprotein clinically equivalent to
calculated low-density lipoprotein? J Clin Lipidol. 2010;4:259–64.
20. Jun KR, Park HI, Chun S, Park H, Min WK. Effects of total cholesterol and triglyceride on the percentage difference between the low-density lipoprotein cholesterol concentration measured directly and calculated using the Friedewald formula. Clin Chem Lab Med. 2008;46:371-5
21. Mora S, Rifai N, Buring JE, Ridker PM. Comparison of LDL Cholesterol Concentrations by Friedewald Calculation and Direct Measurement in Relation to Cardiovascular Events in 27 331 Women. Clin Chem. 2009;55:888–94.
22. Anandaraja S, Narang R, Godeswar R, Laksmy R, Talwar KK. Low-density lipoprotein cholesterol estimation by a new formula in Indian population. Int J Cardiol. 2005;102:117–20.
23. Boshtam M, Ramezani MA, Naderi G, Sarrafzadegan N. Is Friedewald formula a good estimation for low density lipoprotein level in Iranian population? J Res Med Sci. 2012;17:519–22.
24. Baruch L, Chiong VJ, Agarwal S, Gupta B. Discordance of Non-HDL and Directly Measured LDL Cholesterol: Which Lipid Measure is Preferred When Calculated LDL Is Inaccurate? Cholesterol. 2013;2013:502948.doi:10.1155/2013/502948
25. Bittner V. Non-HDL Cholesterol- measurement, interpretation, and significance. Adv Stud Med. 2007;7:8–11.
26. Cui Y, Blumenthal RS, Flaws JA, Whiteman MK, Langenberg P, Bachorik PS, et al. Non-high-density lipoprotein cholesterol level as a predictor of cardiovascular disease mortality. Arch Intern Med. 2001;161:1413–9.
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Published
2018-02-04
How to Cite
Biswas, S. S., Jain, V., Gokhale, P. V., & Agrawal, V. (2018). Friedwald’s Calculation; Is It Reliable in Estimating Risk of Coronary Heart Disease? Friedwald’s Calculation; Is It Reliable in Estimating Risk of Coronary Heart Disease?. National Journal of Integrated Research in Medicine, 8(4), 27–31. Retrieved from http://nicpd.ac.in/ojs-/index.php/njirm/article/view/1274
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