Diabetes and Heart Disease

Diabetes is a strong risk factor for coronary heart disease (CHD) and eradicates the usual delayed onset of fatal and nonfatal CHD in women (when compared with men) (1). Although nearly all observational studies have suggested that estrogen therapy reduces the risk of CHD in postmenopausal women (2), two large clinical trials, the Heart and Estrogen/Progestin Replacement Study (HERS) (3) and the Women’s Health Initiative (WHI) (4), compared daily conjugated equine estrogen plus medroxyprogesterone acetate with placebo and found an early increased risk of CHD and no evidence of long-term benefit. In HERS, a trial conducted in 2,763 women with known CHD, 19% were treated for diabetes at baseline. In WHI, a trial conducted in 16,608 women largely free of CHD at baseline, 4.4% were treated for diabetes at baseline. These subgroups were large enough to test for an interaction of hormone effects by diabetes status; these analyses showed no differential CHD risk or benefit among women with versus without diabetes in the HERS (5) or WHI (4) clinical trials. These clinical trial results are in direct contrast to those reported by Newton et al. (6) in this issue of Diabetes Care , who report in yet another observational study that estrogen has a cardioprotective effect in women with diabetes. In this case-cohort study from a health maintenance organization (HMO), women with known diabetes who were current users of hormone therapy (with or without a progestin) had about half the …