tailieunhanh - NEJM CARDIOVASCULAR DISEASE ARTICLES - Part 5

Trong thử nghiệm WHI của estrogen ngựa liên hợp, một tỷ lệ lớn phụ nữ đã ngừng dùng thuốc nghiên cứu trước khi phiên tòa chấm dứt, và trung bình 1,3 năm đã trôi qua giữa hoàn thành việc thử nghiệm và đo lường canxi động mạch vành. | The new ENGLAND journal of medicine ing center and the large number of women studied providing good statistical power to detect moderate associations. However limitations of the study also warrant consideration. In the WHI trial of conjugated equine estrogens a large percentage of women had stopped taking the study medication before the trial was terminated and an average of years had elapsed between completion of the trial and coronary-artery calcium measurement. Both of these limitations however would lead to an attenuation of the association between treatment with conjugated equine estrogens and coronary-artery calcium scores and would not explain our findings. Although WHI-CACS did not include all participants who had undergone randomization in the estrogen trial and coronary-artery calcium measurements were not available before randomization the distributions of coronary risk factors and behavioral characteristics at baseline were similar among the women receiving estrogen and those receiving placebo. In addition adjustment for a large number of variables potentially related to participation or adherence did not result in a weakening of the associations. It would have been of interest to have coronary-artery calcium measurements for women in the older age groups to allow a comparison of findings for younger and older women. Logistic and operational constraints precluded imaging of the full cohort without a substantial extension of the interval between the discontinuation of study medication and the measurement of coronary-artery calcium. Moreover coronary-artery calcium measurements in the older women would not have necessarily informed or elucidated our findings with respect to CHD among participants 50 to 59 years of age. It is possible that estrogen could reduce coronary-artery calcium scores but still increase the risk of clinical CHD events owing to adverse effects on thrombosis and plaque rupture which are more likely in older women with advanced .