Endocrinology and Metabolism Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
Department of Pathology, School of Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
Iran J Med Sci. 2023 Sep;48(5):484-492. doi: 10.30476/IJMS.2022.95469.2683.
Elevated low-density lipoprotein cholesterol (LDL-C) is a significant risk factor for cardiovascular diseases. LDL-C can be directly measured using various methods, but this requires expensive equipment. Currently, clinical laboratories estimate LDL-C based on Friedewald's formula (FF). We aimed to develop a modified formula based on directly measured LDL-C (D-LDL-C) values in a large population in Southern Iran and compare the results with various other estimation formulas.
The participants of this cross-sectional study were adults aged >18 years living in Southern Iran. Blood samples from 15,200 individuals were collected, and the measured lipid parameters were randomly divided into training (n=10,184) and validation (n=5,016) datasets. A new formula was developed using a linear regression model, and its accuracy was validated. Pearson's correlation and Cohen's kappa were used to determin the relationship between D-LDL-C and calculated LDL-C (C-LDL-C).
The developed formula for the estimation of LDL-C was 0.857 total cholesterol (TC)-0.915 high-density lipoprotein cholesterol (HDL-C)-0.115 triglycerides (TG). Based on our proposed formula, for TG<150 and TG≥150 mg/dL, there was a significant correlation between mean values of D-LDL-C and C-LDL-C (r=0.985 and r=0.974, respectively). Compared to other formulas, C-LDL-C obtained from the proposed formula had the highest correlation with D-LDL-C. The agreement between D-LDL-C and C-LDL-C for TC<200, 200-239, and ≥240 mg/dL was 80.8%, 63.2%, and 67.4%, respectively, indicating a higher level of agreement than other formulas.
The new formula appears to be more accurate than FF when applied to the population of Southern Iran.
升高的低密度脂蛋白胆固醇（LDL-C）是心血管疾病的一个重要危险因素。LDL-C 可以使用各种方法直接测量，但这需要昂贵的设备。目前，临床实验室基于 Friedewald 公式（FF）来估计 LDL-C。我们旨在基于伊朗南部大量人群中直接测量的 LDL-C（D-LDL-C）值开发一种改良公式，并将结果与各种其他估计公式进行比较。
这项横断面研究的参与者为年龄大于 18 岁的居住在伊朗南部的成年人。采集了 15200 人的血样，随机将测量的脂质参数分为训练（n=10184）和验证（n=5016）数据集。使用线性回归模型开发了一个新公式，并对其准确性进行了验证。Pearson 相关系数和 Cohen's kappa 用于确定 D-LDL-C 与计算的 LDL-C（C-LDL-C）之间的关系。
用于估计 LDL-C 的开发公式为 0.857 总胆固醇（TC）-0.915 高密度脂蛋白胆固醇（HDL-C）-0.115 甘油三酯（TG）。根据我们提出的公式，对于 TG<150 和 TG≥150mg/dL，D-LDL-C 和 C-LDL-C 的平均值之间存在显著相关性（r=0.985 和 r=0.974）。与其他公式相比，从建议公式中获得的 C-LDL-C 与 D-LDL-C 的相关性最高。当 TC<200、200-239 和≥240mg/dL 时，D-LDL-C 与 C-LDL-C 之间的一致性分别为 80.8%、63.2%和 67.4%，表明一致性水平高于其他公式。
在伊朗南部人群中应用时，新公式似乎比 FF 更准确。
