HDL-C, triglycerides and carotid IMT: A meta-analysis of 21,000 patients with automated edge detection IMT measurement

- We assess the cross-sectional association of CCAIMT with HDL and triglycerides.
- We included six large observational studies that used the same CCAIMT protocol.
- CCAIMT was associated with low HDL levels independently of LDL levels.
- CCAIMT was not related with triglycerides after controlling for confounding factors.
- Similar findings than those found with clinical events rather than CCAIMT.

ObjectiveCommon carotid artery (CCA) intima-media thickness (IMT), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), but not triglyceride levels, are markers of future cardiovascular events. The relationship between these three factors is, however, unclear.MethodsWe included six large observational studies that used the same harmonized, B-mode ultrasound protocol, the same software for IMT measurement by automatic edge detection on CCA in a plaque-free region, following the Mannheim consensus, and certification of all sonographers. Using the best view of the CCA, the sonographer had to confirm that the quality index was ≥0.5 on a measurement performed on 10-mm length. We used individual data meta-analysis to estimate the cross-sectional associations of lipids with CCA-IMT.ResultsOverall, 21,587 patients with complete information on lipids and CCA-IMT were available. Age- and sex-adjusted CCA-IMT differed by −7.8 μm (95% CI −9.1 to −6.5 μm, P < 0.001) per 1 SD higher HDL-C level. After further adjustment for other atherosclerosis risk factors, the relationship was attenuated, but remained significant (regression coefficient, −3.7 μm; P < 0.001). This was found regardless of LDL-C levels (P for heterogeneity = 0.70). After adjustment for age and sex, triglycerides were positively associated with CCA-IMT, overall and in each LDL-C subgroup, but not after further adjustments for other risk factors.ConclusionsRelationships between HDL-C and triglyceride levels and CCA-IMT were consistent with that previously observed with clinical events by the Emergency Risk Collaboration group, including at low LDL-C levels. This reinforces the need to verify whether raising HDL-C levels decreases both CCA-IMT and future clinical events.