Database hormone study mimics WHI population, but findings differ.
RENO, NEV. -- Women taking hormone therapy had no increase in cardiovascular events and a lower overall death rate, compared with age-matched controls, in a retrospective study using a primary care database and that was designed to mimic the patient population in the Women's Health Initiative.
The findings stand in sharp contrast to results of the WHI, although the investigators set out to match the cohort to the WHI study population in terms of inclusion criteria, study time frame, treatment, and outcome variables.
Dr. Kurt T. Barnhart and his associates at the University of Pennsylvania, Philadelphia, examined the records of women in the United Kingdom General Practice Research Database (GPRD), including 13,658 women aged 55-79 years who were taking combination estrogen / progestin hormone therapy (HT), 37,730 matched controls, and a separate group of younger subjects: 20,654 women on HT and 30,102 controls aged 50-55 years. The results were presented in poster form at the annual meeting of the Society for Gynecologic Investigation.
"We found, in contrast to WHI, that there was no cardioadverse association with hormone replacement therapy. We didn't find it cardioprotective, either. If this had been the WHI, it wouldn't have been stopped," said Dr. Barnhart, of the department of obstetrics and gynecology at the university.
Women were selected for the retrospective study if their demographics matched those of the WHI cohort. They either took 0.625 mg daily of conjugated estrogen and 150 mcg of norgestrel on days 17-28 per cycle, or they served as controls.
In the GPRD, the adjusted hazard ratio for myocardial infarction was 0.95 (0.78-1.16) for older women and 0.91 (0.69-1.20) for younger women. In the WHI, the hazard ratio for nonfatal MI was 1.28 (0.96-1.70); for coronary heart disease deaths (including fatal MI), it was 1.10 (0.65-1.89) (N. Engl. J. Med. 2003;349:523-34). Death from all causes was significantly lower in the older GPRD subjects taking HT than in control subjects, with a hazard ratio of 0.75 (0.65-0.86). It also was lower among the younger women taking hormones vs. younger controls (hazard ratio 0.76 [0.63-0.91]). In the WHI, overall mortality was not affected by HT.
In an interview, Dr. Barnhart called the reduced mortality finding "mildly surprising." Analyses are underway to determine whether missing data may help to account for the mortality findings that differed from the WHI results.
In some cases, the GPRD findings paralleled WHI's. Elevated rates of stroke were seen in both studies, with hazard ratios of 1.23 in the GPRD and 1.41 in WHI results that were reported after the trial was discontinued early (JAMA 2002;288:321-33). Breast cancer was elevated among hormone users in both trials, with hazard ratios of 1.67 and 1.26 in the GPRD and WHI, respectively.
Venous thromboembolic events were elevated in hormone users in both trials, with hazard ratios of 1.55 in the GPRD and 2.22 in the WHI, whereas the risk of colorectal cancer was diminished (with a hazard ratio of 0.56 in the GPRD and 0.63 in the WHI). The hazard ratios for hip fractures were similar in both studies, 0.82 in the GPRD and 0.66 in the WHI.
BY BETSY BATES
Los Angeles Bureau
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|Publication:||Family Practice News|
|Date:||Apr 15, 2007|
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