Effects of Hormone Replacement Therapy on Cardiovascular Risk and Body Composition Parameters

Menopause is defined as the last episode of menstrual bleeding, resulting from the interruption of ovarian function by follicular depletion. It is characterized by the presence of amenorrhea associated with increased levels of FSH and low levels of estradiol. The decline in estrogenic levels is associated with several organic changes, from vasomotor symptoms to impaired bone mass and urogenital atrophy. Although for some patients menopause is asymptomatic or oligosymptomatic, many women experience intense symptoms, which profoundly affect quality of life.

Proper assessment and treatment of postmenopausal women can significantly improve climacteric symptoms. Target tissue, hormone therapy regimen and variations between patients will influence the effects of treatment. Regarding estrogen, the main factors that influence the therapeutic response are the type of hormone used, the dose and the route of administration. The skin metabolizes only a small part of estradiol. Thus, the transdermal route reaches adequate therapeutic levels from a lower dose of estrogen.

The present study aims to evaluate and compare the effects of low dose of oral estradiol associated with oral progesterone and transdermal estradiol associated with vaginal progesterone on variables related to inflammation, coagulation and body composition parameters.

Hormone therapy (HT) was available since 1942 in tablets containing conjugated equine estrogens. Since the 1970s, it has been recommended to add progestogens to the treatment of women with a uterus to prevent endometrial hyperplasia. HT has been shown to be very effective in climacteric syndrome, relieving 90% of hot flushes that affect women in the menopausal transition.

Target tissue, HT regimen and variations between patients will influence the effects of treatment. Regarding estrogen, the main factors that influence the therapeutic response are the type of hormone used, the dose and the route of administration. The most physiological type of estrogen is 17β estradiol, available in the form of gel and adhesive. The skin metabolizes only a small part of estradiol. Thus, the transdermal route reaches adequate therapeutic levels from a lower dose of estrogen. Also, the transdermal route prevents the first hepatic passage, resulting in more stable levels of estradiol in the circulation, without supraphysiological liver concentrations. The bioavailability of estrogen after undergoing metabolism in the liver is approximately 2 to 10% of the total administered. This hepatic passage can result in greater variability in hormone levels, as well as activation of prothrombotic and inflammatory factors. In addition, hepatic metabolism can change the therapeutic effects of estrogen and other pharmacological agents.

The present study aims to evaluate and compare the effects of low dose of oral estradiol associated with oral progesterone and transdermal estradiol associated with vaginal progesterone on variables related to inflammation, coagulation and body composition parameters. This is a prospective randomized controlled study, and the study population includes postmenopausal patients with climacteric symptoms, who have not been using hormone therapy for at least three months. Patients will receive three months of oral hormonal treatment (estradiol 1mg and micronized natural progesterone 200mg 14 days a month) and three months of non-oral hormonal treatment (percutaneous estradiol gel 1.5mg and micronized progesterone 200mg vaginal 14 days a month).

Patients with climacteric symptoms who meet the inclusion and the exclusion criteria will be included in the study. The entire sample will receive both hormonal therapies sequentially and the patients will be divided between the groups (oral therapy and non-oral therapy) to start the study by random allocation. There will be no period of suspension between treatments, that is, at the end of the first three months of the study, the group initially treated with oral therapy starts receiving non-oral treatment for another three months, and the group initially treated with non-oral therapy starts to receive oral therapy also for another three months.

This project has already been approved by the Research Ethics Committee of the Hospital de Clínicas de Porto Alegre. Post-informed written consent will be obtained from all patients, in accordance with health research standards.

The results will be presented as means and standard deviation or medians and interquartile range. Analysis of variance for latin square will be used to evaluate carryover effect. Two-way ANOVA for repeated samples will be used to compare baseline conditions and the two treatments. Bonferroni's adjustment will be used for multiple comparisons. Bivariate correlations between continuous numerical variables will be examined using Pearson or Spearman correlation coefficients, according to the Gaussian or non-Gaussian nature of the variable, respectively. Statistical analysis will be performed using Statistical Package for Social Sciences (SPSS, Chicago, IL, USA), with a value of p \<0.05 being considered significant.

Eligibility Criteria:
Inclusion Criteria:

* Six months or more of amenorrhea and FSH levels\> or = at 35 mIU / ml;
* Menopause for a maximum of three years;
* Mammography and cytology of recent cervix (from the last 12 months);
* Signature of the Informed Consent Form.

Exclusion Criteria:

* Menopause age below 40 years;
* Use of hormonal therapy in the three months preceding the study;
* Uncontrolled diabetes mellitus;
* Endometrial thickening (endometrial thickness greater than 0.5 cm);
* Neoplasm of breast, colon or endometrium;
* History of thromboembolism or established cardiovascular disease;
* Previous hysterectomy;
* Active smoking;
* Use of medication to treat osteoporosis in the last 12 months: bisphosphonates, denosumab, teriparatide, SERMs (selective estrogen receptor agonist).