A Novel LDLC Equation is Superior to the NIH LDLC Equation and the Friedewald Equation

Background

LDLC equations have varying levels of underestimation for the calculated LDLC. Therefore, underestimating LDLC should be avoided as much as possible. We need to establish LDLC equations that underestimate LDLC as little as possible.

Methods

We established the equations with a healthy cohort from Shuyang Hospital and validated the equations with an unselected patient cohort from The Second People's Hospital of Lianyungang. We established the novel LDLC equations by using the regression equation. The relationship between two markers was analysed using Pearson's approach. The 95% limits of measuring agreement within ±2 SD for the LDLC equations was performed using Bland‒Altman analysis. ROC curve analysis was used to predict LDLC levels and the accuracy of the LDLC equation for determining the direct LDLC levels at LDLC cut-offs was assessed.

Results

We obtained two novel LDLC equations (LDL_nonHDLC equation=-0.899+1.195*nonHDLC-0.00347*nonHDLC2 and LDL_TC(total cholesterol) equation=-2.775+1.29*TC -0.00990* TC 2). The correlation coefficient between the novel LDLC equation and the direct LDLC measurements is not lower than that between the LDL_NIH equation and the direct LDLC measurements. The AUCs of our novel LDLC equations were greater than those of the LDL_NIH equation and the LDL_F equation at the LDLC cut-offs for clinical decision-making. The measuring agreement in the methods of the LDL_nonHDL equation is superior to that of the LDL_NIH equation.

Conclusion

LDLC calculated by the novel LDL_nonHDL equation exhibited superiority over the LDL_NIH equation. Combining the LDL_NIH equation and our novel LDLC equation may improve accuracy and avoid undertreatment of high LDLC levels.

Effect of lipoprotein (a) on the analytical determination of low-density lipoprotein cholesterol (LDLc) and its influence on pharmacological treatment with atorvastatin

Lipoprotein(a) (Lp(a)) and Low-density lipoprotein cholesterol (LDLc) is an important risk factor for atherosclerotic cardiovascular disease. The objective of this study was to determine the impact of Lp(a) concentration both on the indirect analytical measurement of LDLc and on the efficacy of dyslipidaemia treatment using the atorvastatin statin. Two retrospective studies were conducted, one with 340 patients and another with 107 patients treated with atorvastatin. Lp(a) concentrations were measured by turbidimetry with an assay independent of the size of the apo(a) isoform. LDLc was calculated using the Friedewald equation and the corrected LDLc was calculated using the Dahlén equation. A strong positive correlation was observed between the serum Lp(a) concentration and the LDLc-overestimation percentage (r = 0.960, p < .001). It was also observed that as the Lp(a) concentration rose there was no significant variation in the percentage decrease in corrected LDLc during atorvastatin treatment (r = 0.186, p > .05). The concentration of LDLc obtained by using the Friedewald equation included Lp(a) cholesterol. The lowering of LDLc in patients treated with atorvastatin depended solely on accessible LDL cholesterol and not on Lp(a) cholesterol.

Retrospective analysis of the cholesterol levels in a European mid-latitude population between 2007 and 2018: controversies and therapeutic implications

BACKGROUND AND AIM OF THE WORK

Coronary heart disease is the leading cause of morbidity and mortality in developed countries and its association with LDL-cholesterol has been well established. During the last decades statin therapy, and an healthy lifestyle, has proven highly effective in reducing cardiovascular event rates. Yet, there is still controversy among national guidelines and clinical practice with regard to LDL-cholesterol measurements. The aim of this study was to verify whether significant changes in cholesterol levels were observed over a relatively long (12 years) period. We also compared the Friedewald-calculated with directly-measured LDL cholesterol in order to verify whether the two methods were equivalent.

METHODS

We retrospectively analyzed 288000 data (total cholesterol, HDL, LDL both directly-measured and Friedewald-calculated, and triglycerides), from 57600 individuals, collected at the San Raffaele Hospital in Milan between 2007 and 2018. Data were statistically analyzed using a linear regression over the 12 years long period of time.

RESULTS

We observed a general decreasing trend in total cholesterol (and an increasing trend in HDL) and a decrease in triglycerides only in the male group. Directly-measured  LDL did not correlate well with calculated LDL.

CONCLUSION

The total cholesterol decrease and the corresponding increment in HDL was attributed to either an increased use of statin and/or an improvement of the general population dietary habits. The latter was further confirmed by the decrease in triglycerides observed in the male group. Based on our data, an alternative method for assessing atherogenics lipoproteins level has been proposed.