Ezetimibe reduces ox-LDL levels
MedWire News: Adding ezetimibe to atorvastatin decreases levels of oxidized low-density lipoprotein (ox-LDL) cholesterol in patients with coronary heart disease (CAD) or an equivalent condition, research shows.
"Ox-LDL level correlates with the vulnerability of atherosclerotic lesions," say Rabih Azar and colleagues from Hôtel Dieu de France Hospital in Beirut, Lebanon.
"Reduction of ox-LDL level by ezetimibe therapy may thus be considered a possible marker of plaque stabilization."
The team randomly assigned 100 patients with CAD or equivalent (diabetes, stroke, peripheral vascular disease) to receive atorvastatin 40 mg/day plus either ezetimibe 10 mg/day or placebo. Most patients had previously been taking statins, and had relatively low cholesterol levels.
After 8 weeks of treatment, patients taking ezetimibe had a larger average reduction in LDL cholesterol than those taking placebo, of 20% versus 10%. This was due to ezetimibe causing a larger reduction in levels of large, buoyant LDL, relative to placebo, with levels falling by 24% versus 10%.
"Thus, the change in lipid profile obtained by ezetimibe was mainly quantitative, while that conferred by statins was quantitative and qualitative," say Azar et al.
Other studies have reported that ezetimibe reduces the largest subgroup of LDL. A study in healthy men, recently reported by MedWire News, showed that ezetimibe added to simvastatin also increased levels of small, dense LDL, resulting in an overall shift toward a more atherogenic profile.
In the current study, however, the two treatment groups had comparable falls in small, dense LDL, and ezetimibe also caused a significant reduction in ox-LDL levels, from 51 to 46 U/l, whereas these did not significantly change with placebo (50 to 51 U/l).
Changes in ox-LDL correlated with changes in LDL cholesterol and the large, buoyant LDL subfraction, but not with small, dense LDL, high-density lipoprotein, or LDL particle size.
The researchers say that small, dense LDL is most prone to oxidization. But the current findings suggest that if patients have fairly well-controlled lipid levels and low levels of small, dense LDL then large, buoyant LDL may be oxidized instead.
Large, buoyant LDL should therefore be "a target of therapy," in such patients, concludes the team in the American Journal of Cardiology.
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By Eleanor McDermid