Publications

CONTEXT

The Heart and Estrogen/progestin Replacement Study (HERS) was a randomized trial of estrogen plus progestin therapy after menopause.

OBJECTIVE

To examine the effect of long-term postmenopausal hormone therapy on common noncardiovascular disease outcomes.

DESIGN AND SETTING

Randomized, blinded, placebo-controlled trial of 4.1 years' duration (HERS) and subsequent open-label observational follow-up for 2.7 years (HERS II), carried out between 1993 and 2000 in outpatient and community settings at 20 US clinical centers.

PARTICIPANTS

A total of 2763 postmenopausal women with coronary disease and average age of 67 years at enrollment in HERS; 2321 women (93% of those surviving) consented to follow-up in HERS II.

INTERVENTION

Participants were randomly assigned to receive 0.625 mg/d of conjugated estrogens plus 2.5 mg of medroxyprogesterone acetate (n = 1380) or placebo (n = 1383) during HERS; open-label hormone therapy was prescribed at personal physicians' discretion during HERS II. The proportions with at least 80% adherence to hormones declined from 81% (year 1) to 45% (year 6) in the hormone group and increased from 0% (year 1) to 8% (year 6) in the placebo group.

MAIN OUTCOME MEASURES

Thromboembolic events, biliary tract surgery, cancer, fracture, and total mortality.

RESULTS

Comparing women assigned to hormone therapy with those assigned to placebo, the unadjusted intention-to-treat relative hazard (RH) for venous thromboembolism declined from 2.66 (95% confidence interval [CI], 1.41-5.04) during HERS to 1.40 (95% CI, 0.64-3.05) during HERS II (P for time trend =.08); it was 2.08 overall for the 6.8 years (95% CI, 1.28-3.40), and 3 of the 73 women with thromboembolism died within 30 days due to pulmonary embolism. The overall RH for biliary tract surgery was 1.48 (95% CI, 1.12-1.95); for any cancer, 1.19 (95% CI, 0.95-1.50); and for any fracture, 1.04 (95% CI, 0.87-1.25). There were 261 deaths among those assigned to hormone therapy and 239 among those assigned to placebo (RH, 1.10; 95% CI, 0.92-1.31). Adjusted and as-treated analyses did not alter our conclusions.

CONCLUSIONS

Treatment for 6.8 years with estrogen plus progestin in older women with coronary disease increased the rates of venous thromboembolism and biliary tract surgery. Trends in other disease outcomes were not favorable and should be assessed in larger trials and in broader populations.

CONTEXT

The Heart and Estrogen/progestin Replacement Study (HERS) found no overall reduction in risk of coronary heart disease (CHD) events among postmenopausal women with CHD. However, in the hormone group, findings did suggest a higher risk of CHD events during the first year, and a decreased risk during years 3 to 5.

OBJECTIVE

To determine if the risk reduction observed in the later years of HERS persisted and resulted in an overall reduced risk of CHD events with additional years of follow-up.

DESIGN AND SETTING

Randomized, blinded, placebo-controlled trial of 4.1 years' duration (HERS) and subsequent unblinded follow-up for 2.7 years (HERS II) conducted at outpatient and community settings at 20 US clinical centers.

PARTICIPANTS

A total of 2763 postmenopausal women with CHD and average age of 67 years at enrollment in HERS; 2321 women (93% of those surviving) consented to follow-up in HERS II.

INTERVENTION

Participants were randomly assigned to receive 0.625 mg/d of conjugated estrogens and 2.5 mg of medroxyprogesterone acetate (n = 1380), or placebo (n = 1383) during HERS; open-label hormone therapy was prescribed at personal physicians' discretion during HERS II. The proportions with at least 80% adherence to hormones declined from 81% (year 1) to 45% (year 6) in the hormone group, and increased from 0% (year 1) to 8% (year 6) in the placebo group.

MAIN OUTCOME MEASURES

The primary outcome was nonfatal myocardial infarction and CHD death. Secondary cardiovascular events were coronary revascularization, hospitalization for unstable angina or congestive heart failure, nonfatal ventricular arrhythmia, sudden death, stroke or transient ischemic attack, and peripheral arterial disease.

RESULTS

There were no significant decreases in rates of primary CHD events or secondary cardiovascular events among women assigned to the hormone group compared with the placebo group in HERS, HERS II, or overall. The unadjusted relative hazard (RH) for CHD events in HERS was 0.99 (95% confidence interval [CI], 0.81-1.22); HERS II, 1.00 (95% CI, 0.77-1.29); and overall, 0.99 (0.84-1.17). The overall RHs were similar after adjustment for potential confounders and differential use of statins between treatment groups (RH, 0.97; 95% CI, 0.82-1.14), and in analyses restricted to women who were adherent to randomized treatment assignment (RH, 0.96; 95% CI, 0.77-1.19).

CONCLUSIONS

Lower rates of CHD events among women in the hormone group in the final years of HERS did not persist during additional years of follow-up. After 6.8 years, hormone therapy did not reduce risk of cardiovascular events in women with CHD. Postmenopausal hormone therapy should not be used to reduce risk for CHD events in women with CHD.

We have exploited strain-specific differences in the NK allorecognition repertoires to generate rat monoclonal antibodies against receptors involved in the control of allogeneic responses by rat NK cells. The monoclonal antibody STOK2 binds to a homodimeric glycoprotein that has been implicated as an inhibitory receptor for an MHC molecule in the PVG strain. In the present study, we haveidentified this glycoprotein as a novel rat Ly49 receptor (Ly49i2) containing an immunoreceptor tyrosine-based inhibitory motif. Ligation of the Ly49i2 receptor induces inhibitory signals, and Ly49i2 coprecipitates with the inhibitory tyrosine phosphatase SHP-1 in stably transfected RNK-16 cells. Moreover, it inhibits natural killing of lymphoblast targets and transfected fibroblast targets expressingthe classical MHC class Ia allele RT1-A1(c). Ly49i2, therefore, is an inhibitory receptor for specific MHC class Ia molecules, similar to inhibitory members of the mouse Ly49 family.

Previous studies of the rapid rejection of MHC-disparate lymphocytes in rats, named allogeneic lymphocyte cytotoxicity, have indicated that rat NK cells express activating receptors for nonclassical MHC class I allodeterminants from the RT1-C/E/M region. Using an expression cloning system that identifies activating receptors associated with the transmembrane adapter molecule DAP12, we have cloned a novel rat Ly-49 receptor that we have termed Ly-49 stimulatory receptor 3 (Ly-49s3). A newly generated anti-Ly-49s3 Ab, mAb DAR13, identified subpopulations of resting and IL-2-activated NK cells, but not T or B lymphocytes. Depletion of Ly-49s3-expressing NK cells drastically reduced alloreactivity in vitro, indicating that this subpopulation is responsible for a major part of the observed NK alloreactivity. DAR13-mediated blockade of Ly-49s3 inhibited killing of MHC-congenic target cells from the av1, n, lv1, and c haplotypes, but not from the u or b haplotypes. A putative ligand was mapped to the nonclassical MHC class I region (RT1-C/E/M) using intra-MHC recombinant strains. Relative numbers of Ly-49s3(+) NK cells were reduced, and surface levels of Ly-49s3 were lower, in MHC congenic strains expressing the putative Ly-49s3 ligand(s). In conclusion, we have identified a novel Ly-49 receptor that triggers rat NK cell-mediated responses.