New Study Tosses a Stone into Hormone Controversy
To take hormone replacements, or not?
That is the $64,000 question for millions of postmenopausal women.
Now research has discovered that use of estrogen therapy could increase the risk of developing kidney stones by 39%.
This new data is from the Women’s Health Initiative study, which followed more than 27,000 women for seven years in a randomized placebo-controlled trial.
The authors of the study conclude: “These findings should be considered in decision making regarding postmenopausal estrogen use.”
Read the full release from the Archives of Internal Medicine below:
Estrogen Therapy May Be Associated With Kidney Stones in Postmenopausal Women
CHICAGO—Use of estrogen therapy is associated with an increased risk of developing kidney stones in postmenopausal women, according to a report in the October 11 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
"Nephrolithiasis [kidney stones] is a common condition that affects 5 percent to 7 percent of postmenopausal women in the United States," according to background information in the article. "Because the process of kidney stone formation is influenced by a variety of lifestyle and other health-related factors, the true impact of estrogen therapy on the risk of kidney stone formation is difficult to infer from observational studies."
Using data from the national Women’s Health Initiative study, Naim M. Maalouf, M.D., of the University of Texas Southwestern Medical Center, Dallas, examined data from two trials: 10,739 postmenopausal women with hysterectomy who received either an estrogen-only treatment or matching placebo and 16,608 postmenopausal women without hysterectomy who received either an estrogen plus progestin treatment or matching placebo. Data were collected for an average of 7.1 years in the estrogen-only trial and 5.6 years for the estrogen plus progestin trial.
A total of 335 cases of kidney stones were reported in the active treatment groups, while 284 cases occurred in the placebo groups. The beginning demographic characteristics and risk factors for kidney stones were similar in the two groups, and the authors found that estrogen therapy was associated with a significant increase in risk of kidney stones. The corresponding annualized incidence rate per 10,000 women per year was 39 in the treatment group and 34 in the placebo group. Development of kidney stones was five times more common in women with a history of kidney stones at the beginning of the study, but was not significantly altered by estrogen therapy. Additionally, there was not a significant link between development of kidney stones and age, ethnicity, body mass index, prior hormone therapy use or use of coffee or thiazide diuretics.
The authors conclude that their results "indicate that estrogen therapy increases the risk of nephrolithiasis in healthy postmenopausal women. The mechanisms underlying this higher propensity remain to be determined. In view of the sizable prevalence of nephrolithiasis in this segment of the population, these findings need to be considered in the decision-making process regarding postmenopausal estrogen use."
Editor’s Note: The Women’s Health Initiative is funded by the National Heart, Lung and Blood Institute, National Institutes of Health, and the U.S. Department of Health and Human Services. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Source: JAMA & Archives
Arch Intern Med. 2010 Oct 11;170(18):1678-85.
Postmenopausal Hormone Use and the Risk of Nephrolithiasis: Results From the Women’s Health Initiative Hormone Therapy Trials.
Maalouf NM, Sato AH, Welch BJ, Howard BV, Cochrane BB, Sakhaee K, Robbins JA.
University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8885. firstname.lastname@example.org.
BACKGROUND: Observational studies examining the role of estrogen in the risk of kidney stone formation have shown conflicting results. However, randomized trial evidence on nephrolithiasis risk with estrogen therapy in postmenopausal women is lacking.
METHODS: We reviewed the incidence of nephrolithiasis in the Women’s Health Initiative estrogen-alone and estrogen plus progestin trials conducted at 40 US clinical centers. A total of 10 739 postmenopausal women with hysterectomy were randomized to receive 0.625 mg/d of conjugated equine estrogens (CEE) or placebo, and 16 608 postmenopausal women without hysterectomy were randomized to receive placebo or estrogen plus progestin given as CEE plus medroxyprogesterone acetate (2.5 mg/d). The incidence of nephrolithiasis was determined for an average follow-up of 7.1 years for the CEE trial and 5.6 years for the estrogen plus progestin trial.
RESULTS: Baseline demographic characteristics and risk factors for nephrolithiasis were similar in the placebo and treatment arms. Estrogen therapy was associated with a significant increase in nephrolithiasis risk from 34 to 39 cases per 10 000 person-years (hazard ratio, 1.21; 95% confidence interval, 1.03-1.44). Censoring data from women when they ceased to adhere to study medication increased the hazard ratio to 1.39 (95% confidence interval, 1.08-1.78). The increased nephrolithiasis risk was independent of progestin coadministration, and effects did not vary significantly according to prerandomization history of nephrolithiasis.
CONCLUSIONS: These data suggest that estrogen therapy increases the risk of nephrolithiasis in healthy postmenopausal women. These findings should be considered in decision making regarding postmenopausal estrogen use. The mechanisms underlying this higher susceptibility remain to be determined. Trial Registration clinicaltrials.gov Identifier: NCT0000611.