CHICAGO – The results of the Women’s Health Initiative randomized clinical trial suggest that postmenopausal women who begin hormone therapy may be putting themselves at risk for coronary heart disease, but a new study from the University of Oklahoma Health Sciences Center suggests that the presence or absence of the metabolic syndrome at baseline is a key determining factor.
"What we found is that if the metabolic syndrome was present, indeed there was a greater risk, greater odds of event, and this was statistically significant. In contrast, if no metabolic syndrome was present, there was no increased risk," said principal investigator Dr. Robert Wild, professor of ob.gyn. and adjunct professor of medicine–cardiology at the center.
The nested case-control study examined the Women’s Health Initiative cohort for an effect modification between elevated baseline risk and hormone therapy (HT). It found 359 incident cases of coronary heart disease (CHD), and matched these to 817 controls without CHD. Controls were matched with a variety of criteria, including prevalent cardiovascular disease at baseline. Trials of estrogen plus progesterone and estrogen alone were analyzed separately and in a pooled analysis.
Metabolic syndrome was defined by ATP (Adult Treatment Panel) III criteria, where three of the following five criteria are met: elevated waist circumference, triglycerides, HDL cholesterol, blood pressure, and fasting glucose.
In the pooled trial analysis of estrogen plus progesterone and estrogen alone, the metabolic syndrome was found to be an effect modifier. The odds ratio for treatment effect was 0.98 for women without the metabolic syndrome and 1.72 for those with the metabolic syndrome.
The individual trials had limited power, said Dr. Wild, but the findings were similar.
"Women without metabolic syndrome had no increase in risk of coronary heart disease vs. placebo, whereas women with metabolic syndrome had elevated risk," said Dr. Wild.
The reasons for this heightened risk might be more advanced stages of atherosclerosis and a heightened thrombogenic state among women with the metabolic syndrome, he said.
"Baseline CHD risk assessment may be helpful to identify women at increased risk for CHD when taking hormone therapy," said Dr. Wild.
Dr. Wild disclosed no significant financial relationships. This study was sponsored by the University of Oklahoma Health Sciences Center, Oklahoma City.