Sriprasert I, Hodis HN, Karim R, et al. Differential effect of plasma estradiol on subclinical atherosclerosis progression in early versus late postmenopause. J Clin Endocrinol Metab. 2019;104:293-300. doi:10.1210/jc.2018-01600.
In 2016, the primary findings of the Early versus Late Intervention Trial with Estradiol (ELITE) demonstrated that oral E2 administered to women who were less than 6 years postmenopause slowed progression of subclinical atherosclerosis as assessed by carotid artery intima-media thickness (CIMT), while it had no effect in women who were at least 10 years postmenopause.1
That trial included 643 healthy women without cardiovascular disease who at enrollment had a median age of 55.4 years in the early postmenopause group (median 3.5 years since menopause) and 63.6 years in the late postmenopause group (median 14.3 years since menopause). The study medications were oral estradiol 1 mg daily plus progesterone vaginal gel for women with a uterus or placebo and placebo gel for a median of 5 years.
The investigators found also that, in contrast with CIMT, cardiac computed tomography (CT) measures of atherosclerosis did not differ significantly between the estradiol and placebo groups, regardless of age.1
Posttrial data analysis revealed a new finding
In a secondary analysis of data from the ELITE trial, Sriprasert and colleagues dug deeper to assess the impact of plasma E2 levels on progression of subclinical atherosclerosis.2
Among 596 women (69.6% white non-Hispanic, 8.7% black, 13.3% Hispanic, and 8.4% Asian/Pacific Islander), E2 levels were available in 248 women in early postmenopause (mean age, 54.7 years) and 348 women in late postmenopause (median age, 63.6 years).
For women in the estradiol-treated group, mean E2 levels during the trial as well as change of E2 levels from baseline were significantly higher in the early postmenopause group than in the late postmenopause group, even though both groups had similar adherence based on pill count. For those in the placebo group, mean E2 levels and change of E2 levels from baseline were equivalent in early and late menopause.
In the E2-treated group and the placebo group combined, the mixed effects analysis of the CIMT progression rate (based on the mean E2 level during the trial) demonstrated that a higher level of E2 was inversely associated with the CIMT progression rate in early postmenopausal women (beta coefficient = -0.04 [95% confidence interval (CI), -0.09 to -0.001] μm CIMT per year per 1 pg/mL estradiol; P = .04). However, a higher level of E2 was positively associated (beta coefficient = 0.063 [95% CI, 0.018 to 0.107] μm CIMT per year per 1 pg/mL estradiol; P = .006) with CIMT progression rate in the late postmenopausal women.
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