Abstract:

Concerns about the cardiovascular safety of hormone replacement therapy (HRT) have persisted for decades, largely shaped by early studies that did not distinguish between age groups or HRT types. This longitudinal review evaluates the cardiovascular outcomes of women under 60 using body-identical HRT, based on real-world data from primary care practices across the UK.

Introduction:

The relationship between HRT and cardiovascular risk has been controversial since the early 2000s. However, more recent data suggest that age, timing of initiation, and type of HRT significantly influence cardiovascular outcomes. This study aims to provide clarity by examining cardiovascular event rates in women under 60 using body-identical estrogen and progesterone therapy, compared to a control group not on HRT.

Methods:

Data were drawn from 8,954 female patients aged 45–59 across 17 NHS-affiliated and private clinics between 2016 and 2023. Women were categorized into two groups:

• HRT group (n=5,342): Initiated body-identical HRT within five years of menopause onset.
• Non-HRT group (n=3,612): Did not use HRT.

Cardiovascular outcomes tracked over an average of 5.2 years included:

• Myocardial infarction (MI)
• Stroke
• Hypertension
• Atrial fibrillation
• All-cause mortality

Adjustments were made for confounding factors including BMI, smoking status, and pre-existing conditions.

Results:

• Reduced incidence of cardiovascular events:
  Women in the HRT group experienced a 28% lower incidence of cardiovascular events compared to the non-HRT group (p < 0.01).
• Lower all-cause mortality:
  All-cause mortality was 22% lower among HRT users.
• No increase in stroke risk:
  Stroke risk was statistically no different between groups, challenging past concerns.
• Hypertension and AF:
  No significant difference in new-onset hypertension or atrial fibrillation.

Discussion:

This review supports the "timing hypothesis," which posits that initiating HRT within 10 years of menopause — particularly in women under 60 — is not only safe but potentially protective against cardiovascular disease. The use of body-identical hormones, especially transdermal preparations, may play a crucial role in this reduced risk profile.

These findings are in contrast to earlier studies that used older, synthetic hormone formulations and included older women with pre-existing risk factors.

Conclusion:

For women under 60, HRT — when appropriately prescribed using body-identical hormones — appears to lower the risk of cardiovascular events and all-cause mortality. Clinicians should be reassured that, for this population, HRT is not only safe but may offer heart-protective benefits.

Authors:

Dr. Louise Newson, Dr. Aisha Khan, Dr. Rebecca Linton

Published by:

Newson Health Research & Education