Changes in remnant and high-density lipoproteins associated with hormone therapy and progression of coronary artery disease in postmenopausal women.

Objective: This study examined the effect of hormone therapy (HT) on the plasma concentration of remnant lipoprotein cholesterol (RLP-C) and high-density lipoprotein (HDL) subpopulations and the contribution of HT-related changes in these lipoproteins to the progression of coronary heart disease (CHD) in postmenopausal women.

Methods: Study participants were 256 women who completed the Estrogen Replacement and Atherosclerosis (ERA) trial, a placebo-controlled, randomized trial that examined the effects of 3.2 years of conjugated equine estrogen (CEE, 0.625 mg/day) or CEE (0.625 mg/day) plus medroxyprogesterone acetate (MPA, 2.5mg/day) on postmenopausal women with established coronary atherosclerosis. Quantitative coronary angiography and plasma RLP-C and HDL subpopulations were assessed at baseline and at follow-up.

Results: Relative to placebo, both CEE and CEE+MPA caused a significant reduction in plasma RLP-C concentrations and a significant increase in alpha1 and alpha2 HDL subpopulations. However, in the HT-treated subjects, faster progression of coronary atherosclerosis was observed in women who experienced the greatest reductions in RLP-C and in prebeta1 HDL subpopulations.

Conclusions: Our data suggest that individual variability in RLP-C and HDL subpopulation response to HT is a predictor of CHD progression. Lipoprotein response to HT may be an indirect marker of susceptibility to other harmful effect of HT in postmenopausal women with established CHD or an indication of formation of dysfunctional lipoproteins.