Concordance and Discordance Between ApoB and LDL-C in a Population with Mixed Hyperlipidemia

This cross-sectional study analyzed 2,103 middle-aged men to quantify the degree of concordance and discordance between plasma ApoB and LDL-C concentrations, and to characterize the metabolic features associated with discordant profiles.

Among men with LDL-C in the normal range, a substantial proportion had elevated ApoB — indicating high atherogenic particle number with low cholesterol content per particle. This ApoB-high/LDL-C-low pattern (discordance favoring ApoB) was strongly associated with features of insulin resistance: elevated triglycerides, low HDL-C, elevated waist circumference, and higher non-HDL-C. Conversely, high LDL-C with normal ApoB was associated with larger, cholesterol-rich LDL particles — less atherogenically dense than the discordant pattern.

The clinical implication is direct. In patients with metabolic syndrome, insulin resistance, or hypertriglyceridemia, LDL-C systematically underestimates cardiovascular risk because the predominant LDL particles are small, cholesterol-depleted, and numerous. Measuring ApoB in this population reveals a high-risk lipid phenotype that LDL-C misses. The magnitude of discordance in this large sample — more than 2,000 subjects — makes clear this is not a rare edge case but a common clinical presentation.

We rate the evidence moderate. A well-powered cross-sectional study in 2,103 men quantifying ApoB-LDL-C discordance and demonstrating that discordance is systematically associated with insulin resistance and atherogenic dyslipidemia — a foundational dataset for understanding when ApoB provides information that LDL-C does not.