ABSTRACT
Considerable evidence supports a relation between postmenopausal hormone therapy and cardiovascular disease. Specifically, long-term use of hormone therapy is associated with substantial protection against heart disease. This protection, observed largely in observational epidemiological studies, may be due, in part, to self-selection bias. Women who take hormones may not be completely comparable to those who do not; women on hormone therapy see a physician regularly and may lead generally healthier lifestyles. However, adjustment for known cardiac risk factors in many of the large studies of homogeneous populations had little impact on their results, implying an equivalent risk status for users and nonusers. To date, however, no randomized trial data in primary prevention have been presented. The effect of progestin added to estrogen therapy has not been adequately assessed, but initial evidence suggests that most of the coronary benefit is probably retained. Considerable controversy exists regarding the effect of hormones in women with established coronary disease, although, like the studies of primary prevention, existing data suggest long-term benefits. On the other hand, the only randomized trial in secondary prevention, the HERS study, failed to show the expected benefits of this approach over a 4-year period of observation.
68 Grodstein and Stampfer
