Effect of hot flushes on cardiovascular autonomic responsiveness: A randomized controlled trial on hormone therapy

Comparative efficacy and safety of estradiol transdermal preparations for the treatment of vasomotor symptoms in postmenopausal women: an indirect comparison meta-analysis

OBJECTIVE

Divigel and Estrogel are estradiol gels for the treatment of postmenopausal women with moderate to severe vasomotor symptoms. They differ with respect to several factors including estradiol concentration and surface application, and cannot be compared solely on the basis of their estradiol dose. No randomized clinical trials have compared them head to head, but both have been compared with placebo. Therefore, the objective of this study was to conduct a systematic review and network meta-analysis of the two estradiol gels.

METHODS

We performed a comprehensive systematic literature review. One publication reporting on one Divigel trial, three publications reporting on two Estrogel trials, and five publications reporting on other estradiol transdermal preparations were identified. Efficacy outcomes were change from baseline in daily hot flush frequency and change from baseline in daily hot flush severity. Safety outcomes were frequency of treatment-related adverse events (AEs) and frequency of treatment-emergent AEs leading to discontinuation. Bayesian indirect treatment comparison meta-analysis of trial-level data was performed in accordance with the International Society for Pharmacoeconomics and Outcomes Research, Academy of Managed Care Pharmacy, National Pharmaceutical Council (ISPOR-AMCP-NPC) Good Practice Questionnaire. All outcomes were compared with respect to doses of the considered preparations.

RESULTS

For hot flush frequency, Divigel 0.25 mg was similar to Divigel 0.5 mg and to Estrogel 0.75 mg, and was statistically significantly superior to Estrogel 1.5 mg. The largest effect was observed with Divigel 1.0 mg (mean difference of 3.91 hot flushes/wk vs placebo), and was statistically significantly superior to all other interventions. The 1.5 mg Estrogel dose was associated with the smallest estimate of efficacy. For hot flush severity, Divigel 0.25 mg was similar to the efficacy of Divigel 0.5 mg, and for 0.25 mg and 0.5 mg of other estradiol gels, but was statistically inferior to Divigel 1.0 mg, Estrogel 0.75 mg, Estrogel 1.5 mg, and the 1.0 and 1.5 mg doses of all other estradiol gels. The estimated efficacy of Divigel 0.5 mg was similar to that of Estrogel 0.75 mg, Estrogel 1.5 mg, and the 0.25 and 0.5 mg doses of other transdermal estradiol preparations. Risks of treatment-related AEs for Divigel 0.25 mg, Divigel 0.5 mg, Estrogel 0.75 mg, and Estrogel 1.5 mg were similar and all were of a slightly higher risk than placebo. Among these, Divigel 1.0 mg, Estrogel 1.5 mg, and other gels 0.5 mg were statistically significantly less safe than placebo. However, for treatment-emergent AEs leading to discontinuation, none of the gels were associated with statistically significantly higher relative risks compared with placebo. In this study, statistically significant refers to the 95% credible intervals used in the Bayesian Network Analysis.

CONCLUSIONS

Using network meta-analysis for indirect treatment comparison, we have shown that the efficacy of Divigel 0.25 mg, as measured by reduced hot flush frequency and severity, was similar to that of Divigel 0.5 mg and of Estrogel 0.75 and 1.5 mg. Overall, our analysis showed that Divigel 1.0 mg provided the best efficacy profile, but that this treatment was also associated with a higher risk of AEs. The network meta-analysis also showed that treatment with Estrogel 1.5 mg was associated with the smallest estimate of reduction in frequency of hot flushes.

Autonomic control of cardiovascular system in pre- and postmenopausal women: a cross-sectional study

OBJECTIVE

The aim of this cross-sectional study was to assess the features of autonomic control of the cardiovascular system in pre- and postmenopausal women.

MATERIAL AND METHODS

We studied 185 postmenopausal women aged 59.3±8.5 years (mean±SD) and 104 premenopausal women aged 45.1±5.8 years. Standard indices of heart rate variability (HRV) (mean heart rate, coefficient of variation, standard deviation of the NN interval (the time elapsing between two consecutive R waves in the electrocardiogram with normal sinus rhythm) (SDNN), square root of the mean squared differences of successive NN intervals (RMSSD), proportion derived by dividing RR50, the number of interval differences of successive NN intervals greater than 50 ms, by the total number of NN intervals (PNN50), and power of low frequency (LF) and high frequency (HF) bands in absolute values and percentages of total spectral power) and index S of synchronization between the 0.1-Hz rhythms in heart rate and photoplethysmogram were compared between these two groups at rest. We assessed the following sex hormones: estradiol, follicle stimulating hormone, dehydroepiandrosterone sulfate, and testosterone.

RESULTS

Mean heart rate and power of LF and HF bands were significantly different (p<0.05) in pre- and postmenopausal women. The autonomic indices were similar in women with natural and surgical menopause. Some indices (coefficient of variation, SDNN, RMSSD, PNN50, and power of LF and HF bands) showed weak correlation with menopause time in women with natural menopause. In women with surgical menopause, a moderate statistically significant correlation was observed only between menopause time and S index (r=-0.41, p=0.039). In premenopausal women, only testosterone correlated weakly with coefficient of variation, SDNN, PNN50, RMSSD, and power of HF band. In postmenopausal women, no correlations were found. We did not find any significant relationship between autonomic indices and hot flashes, assessed by hot flash diary.

CONCLUSION

We did not find a clinically important relationship between cardiovascular autonomic control and menopausal status in women.

Effect of hormone replacement therapy on cardiac autonomic modulation

OBJECTIVE

To investigate the effects of hormone replacement therapy (HRT) on heart rate variability (HRV) in healthy postmenopausal women.

METHODS

Two groups were evaluated: group 1 (G1): 20 women not undergoing HRT (60 ± 5.89 years), group 2 (G2): 20 women undergoing HRT (59 ± 5.70 years). The HRTs involved were either conjugated equine estrogen with or without medroxyprogesterone, synthetic estrogen hormone, estradiol associated with norethisterone acetate or isoflavonoids. Electrocardiogram was recorded in the supine position for 10 min. Spectral analysis included low and high frequencies in absolute (LF and HF) and normalized units (LFnu and HFnu), which are predominantly cardiac sympathetic modulation (CSM) and cardiac vagal modulation (CVM) indicators, respectively. The LF/HF ratio was also calculated. Symbolic analysis involved the following indexes: 0V % (CSM indicator), 1V % (CSM and CVM indicators), 2LV % (predominantly CVM indicator) and 2UV % (CVM indicator). Shannon and conditional entropies were also calculated.

RESULTS

Spectral analysis demonstrated that HRT affected HRV. LF, LFnu and LF/HF ratio were higher (showing increased CSM), while HFnu was lower (representing decreased CVM) in G2 than in G1. Correlations between complexity indices and HFnu were significant and positive only in G1.

INTERPRETATION

Women undergoing HRT presented higher CSM and lower CVM than those who were not. Moreover, the expected positive relationship between CVM and complexity of HRV was found only in control group, thus indicating that CVM in women under therapy drop below a minimal value necessary to the association to become apparent, suggesting an unfavorable cardiac autonomic modulation in spite of HRT.

Menopausal hot flushes do not associate with changes in heart rate variability in controlled testing: a randomized trial on hormone therapy

OBJECTIVE

To compare in controlled cardiovascular autonomic function tests the effects of hormone therapy (HT) on heart rate variability (HRV) responses in postmenopausal women with and without pretreatment hot flushes.

DESIGN

A randomized placebo-controlled trial.

SETTING

Finland, Helsinki University Central Hospital.

POPULATION

A total of 150 recently postmenopausal and healthy women with prospectively evaluated hot flushes.

METHODS

Women (72 with and 78 without hot flushes) were randomized to receive estradiol alone or in combination with medroxyprogesterone acetate or placebo for 6 months. Time and frequency domain measures of HRV were assessed at baseline and after HT with short-term recordings during paced quiet and deep breathing and with active orthostatic tests, both under carefully controlled laboratory conditions to avoid confounding factors present in long-term ambulatory HRV measurements.

MAIN OUTCOME MEASURES

Responses of time and frequency domain measures of HRV to HT.

RESULTS

At baseline HRV was similar in women with and without hot flushes. Pretreatment hot flushes did not associate with changes in time domain parameters of HRV during controlled quiet or deep breathing or active orthostatic tests after different types of HT. However, HT reduced HRV in very low frequency power in women with pretreatment hot flushes (from 371 ± 40 to 258 ± 28 ms(2) , p = 0.018). HT did not have an effect on other frequency domain measures during quiet breathing or active orthostatic tests.

CONCLUSIONS

Hormone therapy did not significantly modify the HRV responses in women with or without hot flushes under controlled short-term measurements of the cardiovascular autonomic nervous system.