Endocrine Abstracts

Objectives: The aim of this study is to compare Friedewaldestimated and directly measured lowdensity lipoprotein cholesterol (LDLC) values and assess the concordance in guideline risk classification between the two methods.

Methods: The data were derived from the 2009 to 2011 Korea National Health and Nutrition Survey (KNHANES). Analysis was done for 6454 subjects with lipid panels – total cholesterol (TC), directly measured LDL-C, high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG).

Results: For subjects with TG <400 mg/dl, overall concordance in guideline risk classification was 79.1%. The Friedewald formula tended to underestimate LDL-C more at higher TG or lower HDL-C levels. Especially, the percent of subjects who were misclassified into a lower risk category was 31% when TG were 200–299 mg/dl; and 45.6% when TG were 300–399 mg/dl. A greater underestimation of LDL-C occurred at higher TG and lower Friedewaldestimated LDL-C levels. Of subjects with a Friedewaldestimated LDL-C <70 mg/dl, 55.4% had a directly measured LDL-C ≥70 mg/dl when TG were 200–399 mg/dl.

Conclusions: The Friedewald equation tends to underestimate LDL-C in highrisk subjects such as hypertriglyceridemia and hypo-HDLcholsterolemia. For these individuals accurate assessment of LDL-C is crucial, and therefore additional evaluation is warranted.