Refining Lipoprotein Assessment in Diabetes: Apolipoprotein B Makes Sense

Om P. Ganda, MD, FACE

Disclosures

Endocr Pract. 2009;15(4):370-376. 

In This Article

Abstract and Introduction

Abstract

Objective: To summarize the data that support the measurement of apolipoprotein B as an accurate reflection of low-density lipoprotein (LDL) particle number and an easily adapted parameter in clinical practice.
Methods: Study findings are reviewed and a flow chart is provided to guide lipid assessment in patients with dyslipidemia.
Results: Current treatment guidelines for lipid management emphasize LDL cholesterol as the primary treatment target in patients at high risk of cardiovascular events. However, LDL cholesterol is a poor surrogate for LDL particle number, particularly in patients with altered LDL composition, such as those with insulin resistance, metabolic syndrome, and type 2 diabetes. Direct measurement of LDL particle number or size is not practical because of methodology and cost considerations. A suggested alternative target in patients with hypertriglyceridemia is non– high-density lipoprotein (HDL) cholesterol. Abundant evidence suggests that even non-HDL cholesterol is an inadequate approximation of the LDL particle number in such patients. The flow chart emphasizes the need to continue achieving the well-established LDL-cholesterol goal, while also considering apolipoprotein B measurement in those with hypertriglyceridemia, rather than relying on the less accurate surrogate of non-HDL cholesterol, when targeting therapy in such patients.
Conclusion: Presented evidence supports the measurement of apolipoprotein B as a more accurate reflection of LDL particle number than non-HDL cholesterol, and it is an easily adapted parameter in clinical practice.

Introduction

Diabetes is the leading cause of cardiovascular morbidity and mortality around the world. In a large meta-analysis of 37 studies, the multivariate-adjusted relative risk for fatal coronary heart disease in persons with diabetes when compared with nondiabetic individuals was a highly significant 3.12 in women and 1.99 in men.[1] Moreover, diabetes may lead to myocardial infarction at a much younger age in both men and women, as shown in a large population database encompassing more than 379 000 people with diabetes compared with more than 9 million people without diabetes. In this population, diabetes resulted in an approximate equivalent of 15 years of premature aging.[2] This was corroborated in the recent analysis of the Framingham study cohort, which concluded that at age 50 years, diabetes confers a life expectancy reduction of 7.5 years in men and 8.2 years in women.[3] Furthermore, in a multitrial analysis of more than 60 000 patients (of whom more than 10 600 had diabetes), patients with diabetes had a worse prognosis than patients without diabetes, with a 40% increase in 30-day mortality and a 33% increase in 1-year mortality.[4]

This review summarizes the data that support the measurement of apolipoprotein B (apo B) as an accurate reflection of low-density lipoprotein (LDL) particle number, and a better predictor of cardiovascular risk, compared to LDL cholesterol and non-HDL cholesterol, and with easily adapted parameter in clinical practice.

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