Postmenopausal HT increases the risk for kidney stones

A review of the incidence of nephrolithiasis among postmenopausal women receiving estrogen monotherapy or estrogen in combination with progestin suggests that HT increases the risk of stone formation, according to researchers at the University of Texas Southwestern Medical Center.

The study involved more than 27,000 healthy postmenopausal women from 40 US clinical centers participating in the Women's Health Initiative HT trials. Approximately 11,000 of the women had undergone a hysterectomy and were randomized to receive either 0.625 mg/d conjugated equine estrogens or placebo.

The remaining women who had not received a hysterectomy were randomized to receive either conjugated equine estrogens plus progestin (2.5 mg/d medroxyprogesterone acetate) or placebo. The women were followed for an average of 6 years.

Maalouf NM, Sato AH, Welch BJ, et al. Postmenopausal hormone use and the risk of nephrolithiasis: results from the Women's Health Initiative hormone therapy trials. Arch Intern Med. 2010;170(18):1678-1685.