ApoB/apoA-I ratio is better than LDL-C in detecting cardiovascular risk

Cardiovascular (CV) events occur even when LDL-C are <100mg/dL. To improve the detection of CV risk we investigated the apoB/apoA-I ratio versus LDL-C in subjects considered normal glucose tolerant (NGT) by oral glucose tolerance test (OGTT).

We enrolled 616 NGT (273 men and 343 women), and we measured insulin resistance, lipid profile, apoB/apoA-I and the factors compounding the metabolic syndrome (MetS). An unfavourable apoB/apoA-I (≥0.9 for males and ≥0.8 for females) was present in 13.9% of 108 patients with LDL-C <100mg/dL: compared to subjects with lower apoB/apoA-I (<0.9 for males and <0.8 for females), they had more elements of MetS and their lipid profile strongly correlated with high CV risk. Out of 314 patients with lower apoB/apoA-I, 40.12% had LDL-C ≥130mg/dL: these retained a more favourable lipid profile than corresponding subjects with elevated apoB/apoA-I ratio. Finally, we found a significant correlation between LDL-C and apoB/apoA-I ratio (r=0.48, p<0.0001).

In NGT with LDL-C <100mg/dL, a higher apoB/apoA-I exhibited an atherogenic lipid profile, indicating that LDL-C alone is insufficient to define CV risk. Independent from LDL-level, when apoB/apoA-I is lower, the lipid profile is, in fact, less atherogenic. This study demonstrates that apoB/apoA-I is at least complementary to LDL-C in identifying the "effective" CV risk profile of asymptomatic NGT subjects.