Ezetimibe alone or in combination with simvastatin increases small, dense low-density lipoproteins in healthy men: a randomized trial

Aims The predominance of small dense low-density lipoproteins (sdLDLs) has been associated with increased cardiovascularrisk. The effect of ezetimibe on LDL subfraction distribution has not been fully elucidated. This study assessedby gradient gel electrophoresis the effects of ezetimibe alone, simvastatin alone, and their combination on sdLDLsubfraction distribution.Methodsand resultsA single-centre, randomized, parallel three-group open-label study was performed in 72 healthy men with a baselineLDL-cholesterol (LDL-C) concentration of 111+30 mg/dL (2.9+0.8 mmol/L). They were treated with ezetimibe(10 mg/day, n ¼ 24), simvastatin (40 mg/day, n ¼ 24), or their combination (n ¼ 24) for 14 days. Blood was drawnbefore and after the treatment period. Generalized estimating equations were used to assess the influence ofdrug therapy on LDL subfraction distribution, controlling for within-subject patterns (clustering). We adjusted forage, body mass index, and baseline concentrations of LDL-C and triglycerides. Ezetimibe alone changed LDL subfractiondistribution towards a more atherogenic profile by significantly increasing sdLDL subfractions (LDL-IVA +14.2%,P ¼ 0.0216 and LDL-IVB +16.7%, P ¼ 0.039; fully adjusted Wald x2 test). In contrast, simvastatin alone significantlydecreased the LDL-IVB subfraction (216.7%, P ¼ 0.002). This effect was offset when simvastatin was combined withezetimibe (LDL-IVB +14.3%, P ¼ 0.44). All three treatments decreased the large, more buoyant LDL-I subfraction,the effects of ezetimibe being the most pronounced (ezetimibe –13.9%, P , 0.0001; combination therapy 27.3%,P ¼ 0.0743; simvastatin 24.6%, P , 0.0001).Conclusion In healthy men, treatment with ezetimibe alone is associated with the development of a pro-atherogenic LDL subfractionprofile. Potentially atheroprotective effects of simvastatin are offset by ezetimibe.This study is registered with ClinicalTrials.gov, identifier no. NCT00317993.