Is hypertriglyceridemia a reliable indicator of cholesterol-depleted apoB particles?

Because cholesterol-depleted apoB particles are thought to be a hallmark of hypertriglyceridemia, American, Canadian and European Lipid Guidelines suggest screening for apoB only in patients with hypertriglyceridemia. Accordingly, this study examines the relationship of triglycerides to the LDL-C/apoB and non-HDL-C/apoB ratios. Methods: The study cohort consisted of 6272 NHANES subjects adjusted for a weighted sample size of 150 million subjects without previously diagnosed cardiac disease. Data was reported by LDL-C/apoB tertiles as weighted frequencies and percent. Sensitivity, specificity, negative predictive and positive predictive values were calculated for triglycerides thresholds of >150 mg/dL and >200 mg/dL. The range of values of apoB for decisional levels of LDL-C and non-HDL-C were also determined Results: Among patients with triglycerides >200 mg/dL, 75.9% were amongst the lowest LDL-C/apoB tertile. However, this represents only 7.5% of the total population. Of patients with the lowest LDL-C/apoB ratio, 59.8% had triglycerides <150mg/dL. Moreover, there was an inverse relationship between non-HDL-C/apoB such that elevated triglycerides were associated with the highest tertile of non-HDL-C/apoB. Finally, the range of values of apoB for decisional levels of LDL-C and non-HDL-C was determined and is so broad- 30.3-40.6 mg/dl apoB for different levels of LDL-C and 19.5 to 27.6 mg/dl apoB for different levels of non-HDL-C- that neither is an adequate clinical surrogate for apoB. Conclusion: Plasma triglycerides should not be used to restrict the measurement of apoB since cholesterol-depleted apoB particles may be present at any level of triglyceride.

Duke Scholars

Author Michael J Pencina Biostatistics & Bioinformatics, Division of Biostatistics