Evaluation of Martin's equation for LDL-C estimation in type 2 diabetes mellitus Egyptian patients

Assessing Performance of Martins's and Sampson's Formulae for Calculation of LDL-C in Indian Population: A Single Center Retrospective Study

Various formulae had been derived to calculate the LDL-C from other lipid profile parameters to supplant the need for direct estimation. Martin's, Sampson's, and Cordova's formulae are recently derived formulae for calculating LDL-C. However, no study has been undertaken till now to verify the newer formulae viz. Martins's and Sampson's in Indian population. The retrospective cross-sectional study was carried out after obtaining approval from the Institutional Ethics Committee on human subject research. The lipid profile data were collected for a period of 17 months from January 2020 to May 2021. The formulae proposed by Friedewald, Cordova, Anandaraja, Martin, and Sampson were used to assess calculated LDL-C. Intraclass correlations were performed to assess the effectiveness of each formula when compared with direct estimation. In our study, we observed that LDL-C calculated using Martin was observed to be closer to that of direct estimation. The bias observed was lowest for Martin's formulae, followed by Sampson's. Intraclass correlation analysis for absolute agreement demonstrated Cordova, Martin, and Sampson to have an average ICC > 0.9, with Martin, and Sampson having a p value < 0.05. Martin fared superior to other formulae in intraclass correlation in patients with LDL > 70. In patients with TG below 200 mg/dL, Martin, and Sampson had a significant correlation with comparable average ICC. However, in patients with TG > 300 mg/dL, Cordova appears to fare better than all other formulae. Our study demonstrated a distinctly superior performance of Martin's formula over Friedewald's formula in the Indian patient population.

Concordance of LDL-C Estimating Equations with Direct Enzymatic Measurement in Diabetic and Prediabetic Subjects

Low-density lipoprotein cholesterol (LDL-C) is a well-established biomarker in the management of dyslipidemia. Therefore, we aimed to evaluate the concordance of LDL-C-estimating equations with direct enzymatic measurement in diabetic and prediabetic populations. The data of 31,031 subjects included in the study were divided into prediabetic, diabetic, and control groups according to HbA1c values. LDL-C was measured by direct homogenous enzymatic assay and calculated by Martin-Hopkins, Martin-Hopkins extended, Friedewald, and Sampson equations. The concordance statistics between the direct measurements and estimations obtained by the equations were evaluated. All equations evaluated in the study had lower concordance with direct enzymatic measurement in diabetic and prediabetic groups compared to the non-diabetic group. Even so, the Martin-Hopkins extended approach demonstrated the highest concordance statistic in diabetic and prediabetic patients. Further, Martin-Hopkins extended was found to have the highest correlation with direct measurement compared with other equations. Over the 190 mg/dL LDL-C concentrations, the equation with the highest concordance was again Martin-Hopkins extended. In most scenarios, the Martin-Hopkins extended performed best in prediabetic and diabetic groups. Additionally, direct assay methods can be used at low values of the non-HDL-C/TG ratio (<2.4), as the performance of the equations in LDL-C estimation decreases as non-HDL-C/TG decreases.

Performance of equations for calculated LDL-C in hypertriglyceridaemia: which one correlates best with directly measured LDL-C?

BACKGROUND

The gold standard for measuring LDL-C is impractical and direct measurements have numerous shortcomings. Older predictive equations are used only with triglycerides (TG's) below 4.52mmol/L. We evaluated the newer equations validated for use in hypertriglyceridaemia by comparison with direct LDL-C.

MATERIALS AND METHODS

Datasets from two platforms (Abbott Architect and Roche Cobas) comprised of a large cohort of 64765 individuals were used to compare the Sampson-National Institutes of Health 2 (S-NIH2) and Extended Martin-Hopkins (E-MH) equations for LDL-C with direct LDL-C (dLDL-C) assays.

RESULTS

With TG's of 4.52-9.04 mmol/L the S-NIH2 equation tended to calculate lower values than measured by dLDL-C and the E-MH equation calculated higher values. Both equations correlated better with the dLDL-C measured on Abbott than Roche with the E-MH equation having more values falling within acceptable concordance levels on both platforms.

CONCLUSION

The E-MH equation correlates better with dLDL-C than the S-NIH2 on both platforms with TG levels up to 9.04mmol/L. With hypertriglyceridaemia, the E-MH equation is less likely than the S-NIH2 equation to underestimate LDL-C when compared to the dLDL-C and will be less likely to underdiagnose patients with LDL-C levels requiring treatment according to current guidelines.

Validation of a novel method for determination of low-density lipoprotein cholesterol levels in Indian patients with type 2 diabetes

BACKGROUND AND AIMS

LDL-cholesterol (LDL-C), being the primary predictor of cardiovascular disease in Type 2 diabetes (T2D), is associated with cardiovascular risk stratification and requires to be estimated with better accuracy with minimal bias. Different formulae have been devised to calculate the LDL-C from the measured lipid profile parameters.

METHODS

In this analytical cross-sectional study, a total of 150 patients with T2D were studied, and blood samples were subjected for lipid profile analysis at the Central Biochemistry laboratory. Different formulae assessed calculated LDL-C.

RESULTS

We observed that all formulae, except Ahmadi, underestimated the LDL-C compared to direct assay. A significant difference was observed between all calculated LDL-C and directly measured LDL-C. On linear regression analysis, the newer formula Martin's has a better approximation with direct assay (slope: 0.9708) than Friedewald (slope: 0.9477). Similarly, Martin's formula exhibited lesser bias (-13.56) in calculating LDL-C in patients with T2D compared with Friedewald's formula.

CONCLUSIONS

The study demonstrated that in patients with T2D, all formulae except Ahmadi significantly underestimated the LDL-C when compared with the direct assay. The newer Martin's formula appeared to more precisely calculate LDL-C in T2D when compared with the traditional Friedewald's formula.

Reliability of Friedewald formula in patients with type 2 diabetes mellitus and its relation to lipid profile in diabetes regulation

Introduction: Many laboratories utilize Friedewald formula (FF) to analyze LDL cholesterol levels of patients including diabetes mellitus (DM). Therefore, it is essential to consider the coherence of results acquired by FF and direct measurement. The number of studies that investigated the effect of lipid parameters, especially TG/HDL cholesterol ratio, on the difference between the two methods is limited. The study was designed to compare LDL cholesterol values obtained by using FF with direct measurement, and to evaluate the relationship between diabetes regulation and lipid profile.

Material and Methods: In the cross-sectional study, 529 type 2 DM patients and 1703 non-DM subjects were divided into four groups regarding TG concentrations. Unlike other studies, the study focuses on direct LDL (DLDL) cholesterol levels obtained with the help of different DLDL cholesterol kits (n=20). The correlations were implemented between HbA1c and lipid profiles.

Results: It was determined that the bias% was over 10% in 24% of patients with 100-199 mg/dL TG levels. The parameter revealed that the most significant difference and the strongest correlation with HbA1c was TG/HDL cholesterol ratio in patients with type 2 DM.

Conclusions: In patients with type 2 DM, even if it was TG <200 mg/dL, LDL calculated with FF should be evaluated together with the TG/HDL cholesterol ratio. Otherwise, direct measurement can be recommended. This ratio is related to diabetes regulation and may be used to monitor patients..