Estrogen plus progestin and the risk of peripheral arterial disease: the Women's Health Initiative.

BACKGROUND Observational studies have reported less frequent carotid atherosclerosis in healthy women taking postmenopausal hormone therapy. Estrogen with progestin did not reduce peripheral arterial events among women with preexisting coronary heart disease. This analysis evaluates clinical peripheral arterial disease among generally healthy women in the Women's Health Initiative randomized trial of estrogen plus progestin. METHODS AND RESULTS The Estrogen Plus Progestin trial assigned 16 608 postmenopausal women, mean age 63.3+/-7.1 years, to daily conjugated estrogens (0.625 mg) with medroxyprogesterone acetate (2.5 mg) or placebo and documented health outcomes over an average of 5.6 years of follow-up. Hospitalization for peripheral arterial disease was infrequent, with annualized rates of 0.08%, 0.06%, and 0.02% for carotid disease, lower extremity arterial disease, and abdominal aortic aneurysm, respectively. The incidence of peripheral arterial events did not differ between treatment groups (hazard ratio [HR] 0.89, 95% confidence interval 0.63, 1.25). The risk was slightly greater among women assigned to active estrogen with progestin in years 1 (HR 1.33) and 2 (HR 1.27), and was slightly lower in later years (HR 0.85 and 0.87 in years 5 and > or =6). Among adherent participants, the hazard ratio for peripheral arterial events was 1.23 (95% confidence interval 0.79, 1.91) over the 5.6 years of follow up. Subgroup analysis identified no significant interactions between estrogen with progestin and baseline characteristics with regard to peripheral arterial disease risk. CONCLUSIONS Among generally healthy postmenopausal women, conjugated estrogens with progestin did not confer protection against peripheral arterial disease.