SAN DIEGO – The use of hormone therapy was associated with a lower urine albumin-to-creatinine ratio and a decreased risk of albuminuria, results from a cross-sectional study suggest.
“This may be useful information for providers taking care of menopausal women who are considering the use of hormone therapy for vasomotor symptoms and are worried about the systemic effects of these medications,” lead study author Dr. Andrea G. Kattah said in an interview after the annual meeting of the American Society of Nephrology. “Though our data only show an association and not cause and effect, hormone therapy is associated with better kidney function in this study.”
Dr. Andrea G. Kattah
Results from many animal studies suggest that estrogen can have beneficial effects on the kidneys, noted Dr. Kattah, who conducted the research with Dr. Vesna D. Garovic and colleagues in the division of hypertension and nephrology at the Mayo Clinic, Rochester, Minn.
“In addition, in human studies of chronic kidney disease, premenopausal women tend to have slower progression of kidney disease than men,” she said. “Studies on the effects of hormone therapy on kidney function in women have had variable results. We wanted to look at the association of hormone therapy and renal function in a large, multiethnic cohort with well-defined health conditions that may confound the relationship between hormone therapy and renal disease.”
Study participants included 2,217 women enrolled in the Family Blood Pressure Program, a multinetwork effort to study the genetics of hypertension. During a study visit between 2000 and 2004, the women completed questionnaires about medical history, menopausal status, and use of hormone therapy (HT) in the past month. Clinicians also took their blood pressure, measured their body mass index, and drew blood to determine levels of serum creatinine and urine albumin-to-creatinine ratio (UACR).
Of the 2,217 women, 673 were on HT and 1,544 were not, and their mean ages were 60 years and 63 years, respectively.
In unadjusted analysis, Dr. Kattah and her associates found that UACR was significantly lower in those on HT, compared with those who were not (3.5 mg/g creatinine vs. 5.2 mg/g creatinine, respectively, P less than .001), as was the number of women with an estimated glomerular filtration rate (eGFR) of less than 60 mL/min per 1.73 m2 (7% vs. 10%, P = .003).
After adjusting for renal and cardiovascular risk factors including age, race, smoking, diabetes, hypertension, and family history of hypertension, the use of HT was still significantly associated with a lower UACR and decreased risk of microalbuminuria (odds ratio, 0.61). The association between HT and eGFR of less than 60 mL/min per 1.73 m2 was no longer significant after adjustment, but there was a trend toward higher eGFR and fewer women with an eGFR of less than 60 mL/min per 1.73 m2 among those on HT.
“Not surprisingly, the women taking hormone therapy were different than those who were not, and they generally had fewer health problems, such as diabetes and hyperlipidemia,” Dr. Kattah said. “However, after taking these differences into account in our models, we still found a significant decrease in the risk of having microalbuminuria in those on hormone therapy.”
Dr. Kattah acknowledged certain limitations of the study, including the fact that its design is “cross-sectional and cannot answer the question of whether or not hormone therapy can improve kidney function.
In addition, “we do not have data on how long women were taking hormone therapy, which other studies have suggested is an important factor.”
The researchers reported having no financial disclosures.