A Direct measurement for LDL-cholesterol increases hypercholesterolemia prevalence; Comparison with Friedewald calculation

LDLコレステロール直接法は高コレステロール血症有病率を増加させる; Friedewald計算法との比較

亀崎 文彦; 園田 信成*; 中田 靖*; 尾辻 豊*

Kamezaki, Fumihiko; Sonoda, Shinjo*; Nakata, Sei*; Otsuji, Yutaka*

Direct measurement by homogenous assays has recently been applied to measuring low-density lipoprotein-cholesterol (LDL-C) and has replaced the Friedewald calculation in Japan, but it remains unclear how direct measurement compares with the Friedewald calculation in evaluating hypercholesterolemia. The aim of this study was to determine the effect of the two methods on the diagnosis of hypercholesterolemia. In a total of 1,655 workers from our institution, we investigated the LDL-C levels by the direct and Friedewald methods. Direct LDL-C showed a significantly positive correlation with Friedewald LDL-C (R=0.975, P0.0001). On the other hand, the mean direct LDL-C was 5.9 mg/dl higher than mean Friedewald LDL-C (126.730.6 mg/dl vs. 120.830.5 mg/dl, P0.0001), and direct LDL-C was higher in 89.1% of the study population. The frequency of study subjects diagnosed with hypercholesterolemia, defined as LDL-C 140 mg/dl, was significantly higher in the direct measurement than in the Friedewald calculation (31.7% vs. 25.1%, P0.0001). In conclusion, we demonstrated that the direct measurement showed a higher rate of hypercholesterolemia prevalence than the Friedewald calculation indicated. This result suggests that we have to give careful consideration to the method for measuring LDL-C in the clinical diagnosis and management decisions of hypercholesterolemia.