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

Abstract 

Background and aims

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).

Methods and results

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).

Conclusions

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.

Keywords: Cardiovascular risk, Apob/Apoa-I ratio, LDL-C, Insulin resistance, Metabolic syndrome

Acronyms: CV, Cardiovascular, NGT, Normal glucose tolerant, OGTT, Oral glucose tolerance test, MetS, Metabolic syndrome, LDL-C, Low density lipoprotein Cholesterol, VLDL, Very low-density, IDL, Intermediate-density, HDL, High-density lipoproteins, NCPE, National Cholesterol Education Program, TG, Triglycerides, non-HDL-C, Non-HDL-cholesterol, HDL-C, HDL-cholesterol, 0′, Baseline, 2 hours, (2h), Gly-0′, Baseline glycaemia, Ins-0′, Baseline, Insulinemia, Gly-2h, 2h glycaemia, Ins-2h, 2h insulinemia, WC, Waist circumference, HOMA, Homeostatic model assessment, M, Means, SD, Standard deviations