Hemostatic markers in healthy postmenopausal women during intranasal and oral hormone therapy

Are all estrogens created equal? A review of oral vs. transdermal therapy

BACKGROUND

To compare oral and transdermal delivery systems in domains of lipid effects; cardiovascular, inflammatory, and thrombotic effects; effect on insulin-like growth factor, insulin resistance, and metabolic syndrome; sexual effects; metabolic effects including weight; and effects on target organs bone, breast, and uterus.

METHODS

Review of the literature 1990-2010. Studies selected on basis of applicability, quality of data, and relationship to topic.

RESULTS

Data applicable to the comparisons of oral versus transdermal delivery systems for postmenopausal estrogen therapy were utilized to perform a review and formulate conclusions.

CONCLUSIONS

Significant differences appear to exist between oral and transdermal estrogens in terms of hormonal bioavailability and metabolism, with implications for clinical efficacy, potential side effects, and risk profile of different hormone therapy options, but neither results nor study designs are uniform. Bypassing hepatic metabolism appears to result in more stable serum estradiol levels without supraphysiologic concentrations in the liver. By avoiding first-pass metabolism, transdermal hormone therapy may have less pronounced effects on hepatic protein synthesis, such as inflammatory markers, markers of coagulation and fibrinolysis, and steroid binding proteins, while oral hormone therapy has more pronounced hyper-coagulant effects and increases synthesis of C-reactive protein and fibrinolytic markers. Both oral and transdermal delivery systems have beneficial effects on high-density lipoprotein cholesterol to low-density lipoprotein cholesterol ratios (oral>transdermal), while the transdermal system has more favorable effects on triglycerides. Incidence of metabolic syndrome and weight gain appears to be slightly lower with a transdermal delivery system. Oral estrogen's significant increase in hepatic sex hormone binding globulin production lowers testosterone availability compared with transdermal delivery, with clinically relevant effects on sexual vigor.

Less mammographic density after nasal versus oral administration of postmenopausal hormone therapy

OBJECTIVE

Nasal administration gives a more acute but shorter rise in serum hormone levels than oral administration and may therefore have less effect on the fibroglandular tissue in the breasts. We studied the change in mammographic breast density after nasal vs. oral administration of postmenopausal hormone therapy (PHT).

METHODS

We studied participants in a randomized, controlled trial on the impact of nasal vs. oral administration of PHT (combined 17β-estradiol plus norethisterone) for 1 year. Two radiologists classified mammographic density at baseline and after 1 year into four categories. Also, the percentage density was calculated by a computer-based method. The main outcome measure was the difference in the proportion of women with an increase in mammographic density category after 1 year between the nasal and oral groups. Also, the change in the percentage density was calculated.

RESULTS

The study group comprised 112 healthy postmenopausal women (mean age 56 years), of whom 53 received oral and 59 intranasal PHT. An increase in mammographic density category after 1 year was seen in 20% of the women in the nasal group and in 34% of the oral group. This resulted in a non-significant difference in the proportion of women in whom mammographic breast density had increased by 214% (95% confidence interval (CI) 230% to 2.7%). The mean change in percentage density was 21.2% in the nasal group and + 1.2% in the oral group, yielding a 22.4% differential effect (95% CI 27.3% to 2.5%).

CONCLUSIONS

One year of nasal PHT gave a smaller, although not statistically significant, increase in mammographic density than oral PHT. Remaining issues are the relation between the route of administration of PHT and breast complaints and breast cancer risk.