scholarly journals Comparison of Regression Equation and Friedewald’s Formula with Direct Measurement of Low-density Lipoprotein Cholesterol in Bangladeshi Population

2013 ◽  
Vol 6 (1) ◽  
pp. 143-152
Author(s):  
M. Saiedullah ◽  
N. Chowdhury ◽  
M.A.H. Khan ◽  
S. Hayat ◽  
S. Begum ◽  
...  
Keyword(s):  
Linear Regression ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Regression Equation ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Regression Equations ◽  
Validation Group ◽  
Low Density Lipoprotein Cholesterol ◽  
Bangladeshi Population

Friedewald’s formula (FF) is the most widely used formula in clinical practice to calculate low-density lipoprotein cholesterol (LDLC) from total cholesterol (TC), triglyceride (TG) and high-density lipoprotein cholesterol (HDLC). But this formula frequently underestimates LDLC. The aim of this study was to derive a regression equation (RE) to abolish the underestimation and to compare the performance of RE and FF in Bangladeshi population. RE was derived from 531 lipid profiles (equation derivation group) for the calculation of LDLC by multiple linear regression analysis. The RE was then used to calculate LDLC in another 952 subjects (equation validation group). LDLC calculated by RE and FF were compared with measured LDLC by appropriate statistical analyses. In equation validation group, measured LDLC, LDLC calculated by RE and FF were 2.97±0.81, 2.91±0.80 and 2.72±0.93 mmol/L respectively. Precision (r) was 0.9525 for RE and 0.9193 for FF. Passing & Bablok linear regression equations against measured LDLC were y = 0.9792x + 0.007 for RE and y = 1.1412x – 0.6781 for FF. Accuracy within ±12% of measured LDLC was 79% and 57% for RE and FF, respectively. The derived RE is more accurate than FF for the calculation of LDLC in Bangladeshi population.  Keywords: Lipoprotein cholesterol; Friedewald’s formula; Bangladeshi population.  © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.  doi: http://dx.doi.org/10.3329/jsr.v6i1.14864 J. Sci. Res. 6 (1), 143-152 (2014)

scholarly journals Validation of the Modified Friedewald’s Formula to Calculate Low-density Lipoprotein Cholesterol in Bangladeshi Population

2012 ◽  
Vol 30 (3) ◽  
pp. 141-144
Author(s):  
Mimi Parvin ◽  
Muhammad Saiedullah ◽  
Aminul Haque Khan ◽  
Muhammad Rezwanur Rahman ◽  
Md Saiful Islam
Keyword(s):  
Correlation Coefficient ◽  
Ldl Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Serum Triglyceride ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Bangladeshi Population ◽  
Modified Formula

Objective: A modification of Friedewald’s formula was proposed to calculate LDL cholesterol in Bangladeshi population up to serum triglyceride concentration of 1000 mg/dL. The aim of this study was to validate the modification of Friedewald’s formula in Bangladeshi population.Methods: Serum total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol concentrations were measured in specimens obtained form 314 adult Bangladeshi subjects selected conveniently. LDL cholesterol concentrations were also calculated by modified Friedewald’s formula and original Friedewald’s formula. Results were expressed as mean ± SD and calculated LDL cholesterol was compared with measured LDL cholesterol by two-tailed paired t test and Pearson’s correlation coefficient (r).Results: The mean ± SD of measured LDL cholesterol was 138.3 ± 54.58 mg/dL. LDL cholesterol calculated by modified Friedewald’s formula and original Friedewald’s formula were 135.9 ± 59.26 mg/dL (P>0.05) and 123.5 ± 65.75 mg/dL (P<0.001) respectively. Compared to measured LDL cholesterol, calculated LDL cholesterol were 2.47 mg/ dL and 17.20 mg/dL lower for modified formula and original formula respectively. The correlation coefficient (r) with measured LDL cholesterol was 0.8601 (P<0.0001) for LDL cholesterol calculated by the modified Friedewald’s formula and 0.8565 (P<0.0001) for the LDL cholesterol calculated by the original Friedewald’s formula.Conclusion: The study validates the modified Friedewald’s formula to calculate LDL cholesterol in Bangladeshi    population. DOI: http://dx.doi.org/10.3329/jbcps.v30i3.12463 J Bangladesh Coll Phys Surg 2012; 30: 141-144

scholarly journals Comparison of calculated versus directly-measured low-density lipoprotein-cholesterol: An evaluation of ten formulas for an HIV-positive population in Sub-Saharan Africa

2017 ◽  
Vol 9 (02) ◽  
pp. 111-115 ◽  
Author(s):  
Ifeyinwa Osegbe ◽  
Martin Ugonabo ◽  
Chinwe Chukwuka ◽  
Ijeoma Meka ◽  
Nnamdi Nwosu
Keyword(s):  
Linear Regression ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Hiv Positive ◽  
Low Density ◽  
Strong Positive Correlation ◽  
Low Density Lipoprotein Cholesterol ◽  
Positive Correlation ◽  
Positive Population

Abstract BACKGROUND: Low-density lipoprotein cholesterol (LDLC) is a modifiable risk factor for atherosclerotic cardiovascular disease, therefore needs to be assessed and monitored. Direct homogeneous assays and various formulas exist to determine LDLC. We aimed to compare the directly measured LDL (dLDLC) with ten formulas for estimating LDLC. MATERIALS AND METHODS: This was a 2-year retrospective study of fasting lipid profile results obtained from HIV-positive patients attending an outpatient clinic at the University of Nigeria Teaching Hospital, Enugu, Nigeria, using homogeneous direct assays. Estimated LDLC was determined using ten formulas. Pearson’s correlation, Bland–Altman plots, and linear regression were performed. Statistical significance was P < 0.05. RESULTS: Three thousand four hundred and eighty-two lipid results with mean ± standard deviation (SD) dLDLC of 2.1 ± 1.1 mmol/L were included in this study. There was a strong, positive correlation between Friedewald’s LDLC and dLDLC n = 3412, r = 0.84, P < 0.001, but linear regression demonstrated a proportional bias P = 0.005. Ahmadi’s equation showed the worst correlation n = 3482, r = 0.35, P < 0.001, but when applied to samples with triglyceride (TG) <1.13 mmol/L (100 mg/dl), the correlation showed a strong, positive relationship n = 1395, r = 0.80, P < 0.001, and no proportional bias P = 0.86. Teerankanchana’s equation was the only formula that showed no difference between its LDLC and dLDLC (n = 3482, P = 0.056). It also demonstrated strong, positive correlation (n = 3482, r = 0.84, P < 0.001) and had a mean difference ± SD of −0.68 ± 0.63. CONCLUSION: Teerankanchana’s formula showed good correlation and minimal bias with dLDLC at all TG levels. Moreover, linear regression showed no difference in the two. It seems to be the most suitable formula for estimating LDLC in our HIV-positive population.

scholarly journals Comparison of modified Friedewald’s formula with direct measurement of low-density lipoprotein cholesterol in Bangladeshi population

2014 ◽  
Vol 39 (3) ◽  
pp. 120-123
Author(s):  
N Chowdhury ◽  
M Saiedullah ◽  
MAH Khan ◽  
MR Rahman
Keyword(s):  
Direct Measurement ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Absolute Bias ◽  
The Mean ◽  
Bangladeshi Population ◽  
Modified Formula

A modification of Friedewald’s formula to estimate serum low-density lipoprotein cholesterol (LDLC) up to serum triglyceride (TG) level of 11.3 mmol/L in Bangladeshi population has recently been published. The aim of this study was to compare the modified formula with direct measurement of LDLC in Bangladeshi population in a different setting. One thousand and fifty two specimens from adult subjects were analyzed. Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), LDLC and TG were measured by standard methods. The modified Friedewald’s formula was applied to estimate LDL cholesterol concentration. Results were expressed as mean ± SD and calculated LDLC was compared with measured LDLC by two-tailed paired t test, Bland-Altman plot for absolute bias, Pearson’s correlation coefficients of calculated LDLC with measured LDLC and Passing & Bablok regression equation of calculated LDLC against measured LDLC. The mean ± SD of measured LDLC was 2.98±0.82 mmol/L. LDLC calculated by modified Friedewald’s formula was 2.77±0.86 mmol/L. The mean absolute bias was –0.20±0.32 mmol/L, Pearson’s correlation coefficient (r) was 0.9293 (P<0.0001) and Passing & Bablok regression equation was y= – 0.3856+1.0597x for modified formula up to serum TG?11.3 mmol/L. Compared to original Friedewald’s formula, performance of the modified Friedewald’s formula was better up to serum TG?4.52 mmol/L. The study reveals that the modified Friedewald’s formula may be used to calculate LDLC approximately in Bangladeshi population. DOI: http://dx.doi.org/10.3329/bmrcb.v39i3.20312 Bangladesh Med Res Counc Bull 2013; 39: 120-123

scholarly journals Evaluation of the Novel Method and the Regression Equation for Calculation of Low-Density Lipoprotein Cholesterol

2015 ◽  
Vol 5 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Muhammad Saiedullah ◽  
Nasreen Chowdhury ◽  
Md Aminul Haque Khan
Keyword(s):  
Direct Measurement ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
The Novel ◽  
Low Density Lipoprotein Cholesterol ◽  
Mean Values ◽  
Novel Method ◽  
Bangladeshi Population

Background: Friedewald’s formula (FF) is used worldwide to calculate low-density lipoprotein cholesterol (LDL-chol). But it has several shortcomings: overestimation at lower triglyceride (TG) concentrations and underestimation at higher concentrations. In FF, TG to very low-density lipoprotein cholesterol (VLDL-chol) ratio (TG/VLDL-chol) is considered as constant, but practically it is not a fixed value. Recently, by analyzing lipid profiles in a large population, continuously adjustable values of TG/VLDL-chol were used to derive a novel method (NM) for the calculation of LDL-chol. Objective: The aim of this study was to evaluate the performance of the novel method compared with direct measurement and regression equation (RE) developed for Bangladeshi population. Materials and Methods: In this cross-sectional comparative study we used lipid profiles of 955 adult Bangladeshi subjects. Total cholesterol (TC), TG, HDL-chol and LDL-chol were measured by direct methods using automation. LDL-chol was also calculated by NM and RE. LDL-chol calculated by NM and RE were compared with measured LDL-chol by twotailed paired t test, Pearson’s correlation test, bias against measured LDL-chol by Bland-Altman test, accuracy within ±5% and ±12% of measured LDL-chol and by inter-rater agreements with measured LDL-chol at different cut-off values. Results: The mean values of LDL-chol were 110.7 ± 32.0 mg/dL for direct measurement, 111.9 ± 34.8 mg/dL for NM and 113.2 ± 31.7 mg/dL for RE. Mean values of calculated LDL-chol by both NM and RE differed from that of measured LDL-chol (p<0.01 for NM and p<0.0001 for RE). The correlation coefficients of calculated LDL-chol values with measured LDL-chol were 0.944 (p<0.0001) for NM and 0.945 (p<0.0001) for RE. Bland- Altman plots showed good agreement between calculated and measured LDL-chol. Accuracy within ±5% of measured LDL-chol was 49% for NM, 46% for RE and within ±12% of measured LDL-chol was 79% for both NM and RE. Inter-rater agreements (?) between calculated and measured LDL-chol at LDL-chol <100 mg/dL, 100–130 mg/dL and >130 mg/dL were 0.816 vs 0.815, 0.637 vs 0.649 and 0.791 vs 0.791 for NM and RE respectively. Conclusion: This study reveals that NM and RE developed for Bangladeshi population have similar performance and can be used for the calculation of LDL-chol. DOI: http://dx.doi.org/10.3329/jemc.v5i1.21491 J Enam Med Col 2015; 5(1): 10-14

A new formula for estimation of low-density lipoprotein cholesterol in an ethnic Chinese population

2015 ◽  
Vol 53 (11) ◽  
Author(s):  
Ching-Yun Hu ◽  
Chia-Lin Lee ◽  
Wayne H.-H. Sheu ◽  
Jun-Sing Wang ◽  
I-Te Lee ◽  
...  
Keyword(s):  
Total Cholesterol ◽  
Chinese Population ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Lipid Lowering ◽  
Low Density ◽  
Validation Group ◽  
Low Density Lipoprotein Cholesterol ◽  
Testing Group

AbstractLow-density lipoprotein cholesterol (LDL-C) is an established risk factor for cardiovascular disease and is usually estimated by the Friedewald formula (FF) calculated from three parameters, namely, total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C). We aimed to develop a new and simple formula (NF) for LDL-C estimation.This cross-sectional study enrolled two study populations (a testing group, n=16,749, and a validation group, n=4940). Linear regression analysis was used in the testing group to investigate the association between measured LDL-C (mLDL-C) and TC concentration, and was verified in the validation group.The NF yielded an estimated LDL-C (eLDL-C) equal to 0.75×total cholesterol–0.6465 (mmol/L). For the subjects with TC between 2.58 and 7.74 mmol/L, the difference between mLDL-C and eLDL-C using the NF was less than that from the FF (testing group: –0.04 to –0.20 vs. –0.28 to –0.38 mmol/L; validation group: 0.01 to –0.12 vs. –0.23 to –0.30 mmol/L; p<0.001, respectively). The predictability of the NF was not inferior to that of the FF in subjects with different triglyceride and HDL-C concentrations, and was not affected by diabetes diagnosis and statin use. However, the NF performed similar to or worse than the FF at TC concentrations <2.58 mmol/L and >7.74 mmol/L, respectively.In the Chinese population, the accuracy of eLDL-C measurement with the NF was better than that with the FF, especially in subjects with TC levels between 2.58 and 7.74 mmol/L. The NF is simple and may be used for screening as well as for follow-up of patients on lipid lowering agents.

Friedewald’s Formula is Applicable up to Serum Triacylglycerol to Total Cholesterol Ratio of Two in Bangladeshi Population

1970 ◽  
Vol 2 (2) ◽  
pp. 21-25 ◽  
Author(s):  
Muhammad Saiedullah ◽  
Aradhan Sarkar ◽  
Syed Muhammad Kamaluddin ◽  
Shahnaj Begum ◽  
Shoma Hayat ◽  
...  
Keyword(s):  
Total Cholesterol ◽  
Direct Method ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Cholesterol Ratio ◽  
Triacylglycerol Concentration ◽  
Bangladeshi Population

Friedewald’s formula is the most frequently used formula for the calculation of serum lowdensity lipoprotein cholesterol from serum total cholesterol, serum triacylglycerol and serum high-density lipoprotein cholesterol. Most laboratories use serum triacylglycerol concentration of 400 mg/dl as upper cut-off limit for the calculation of LDL cholesterol, but a combination of serum triacylglycerol to total cholesterol ratio and serum triacylglycerol may have more advantages than serum triacylglycerol concentration alone to use Friedewald’s formula effectively. The aim of this study was to determine the upper cut-off limit of serum triacylglycerol concentration and serum triacylglycerol to total cholesterol ratio to calculate LDL cholesterol using Friedewald’s formula in Bangladeshi population. Serum total cholesterol, serum triacylglycerol, serum high-density lipoprotein cholesterol and serum lowdensity lipoprotein cholesterol were measured by direct method on 644 sera obtained from adult Bangladeshi study subjects after 12 hours of fasting. Serum low-density lipoprotein cholesterol was also calculated by using Friedewald formula. Low-density lipoprotein cholesterol obtained by Friedewald’s formula in this study was compared with that obtained by direct method in different level of triacylglycerol and also in different triacylglycerol to total cholesterol ratio. Friedewald’s formula underestimates low-density lipoprotein cholesterol when serum triacylglycerol concentration >300 mg/dL. But when direct serum low-density lipoprotein cholesterol was compared with low-density lipoprotein cholesterol calculated using Friedewald’s formula up to serum triacylglycerol to total cholesterol ratio of 2, underestimation subsides, and the serum triacylglycerol level up to 700 mg/dl could be confidently included for the calculation of low-density lipoprotein cholesterol by Friedewald’s formula. Friedewald’s calculation formula can be confidently used up to serum triacylglycerol concentration of 700 mg/dl in Bangladeshi population, provided the serum triacylglycerol to total cholesterol ratio is two or less. Key Words: Friedewald Formula; Low-Density Lipoprotein Cholesterol

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