Use of conjugated equine estrogens (CEEs) to relieve the vasomotor symptoms of menopause is associated with about twice the risk of venous thrombosis compared with oral estradiol, according to a population-based case-control study of postmenopausal women (Smith NL et al. JAMA Intern Med. doi:10.1001/jamainternmed.2013.11074 [published online September 23, 2013]).
The study involved 384 women in a large health maintenance organization who were current users of CEEs or estradiol between 2003 and 2009; the researchers compared those who experienced venous thromboses (68 women), myocardial infarction (67), or ischemic stroke (48) with 201 matched controls. In addition to the increased risk of venous thrombosis, the risk of myocardial infarction was higher among users of CEEs compared with users of estradiol (although the relationship did not reach statistical significance), but no increased risk of stroke was found.
Slomski A. Risks Higher for Some Estrogen Drugs. JAMA. 2013;310(20):2139. doi:10.1001/jama.2013.282477