MHT and CHD: Evidence and Suggestions

In today’s lunch time symposium Dr Stevenson kicked things off with a presentation on the cardiovascular consequences of menopause and HRT, presenting data that highlighted the importance of age in determining the benefit MHT may have on CHD.

What have we learnt from the data currently available? A large scale study carried out in 10,500 women by Lokkegaard et al, demonstrated that women with premature menopause (under the age of 40) have double the relative risk of experiencing coronary heart disease compared to those aged 45 or above.  This increased risk is a result of metabolic changes which are seen during menopause including; increased total cholesterol, increased triglyceride, increased lipoprotein and increased small dense LDL particles. Other factors can also have an impact including; increased blood pressure, altered fat distribution and increased inflammatory markers.

As both menopause and age increase the risk of CHD, analysis has been done to see what impact HRT has on risk. Data from a number of studies show that HRT use has resulted in a 40-50% reduction in cardiovascular occurrences.  A study from Schlipak et al. also demonstrated that HRT users had better survival rates from heart attacks, than women who were not on HRT treatment, whilst data from Rosano et al. showed patients on HRT following a myocardial ischaemia were able to spend longer on exercise on the road to recovery. These displayed benefits are due to the positive impacts of HRT on the metabolic pathway:

  • decreased total cholesterol
  • decreased LDL cholesterol
  • increased or decreased HDL and triglycerides
  • decreased lipoprotein 
  • increased small dense LDL clearance
  • increased postprandial lipid clearance
  • decreased LDL oxidation

Although many clear benefits have been observed, studies in older women have shown no clear benefit in reduction of CHD. The Finnish study has shown that HRT in women under the age of 60 significantly reduced CHD death whilst use of HRT in women over 60 years old had no impact on CHD death. This was supported by the Cochrane 2014 review which showed that women who started HRT treatment less than 10 years from menopause onset enjoyed a significant reduction in relevant risk of CHD whilst those who started treatment more than 10 years from menopause onset showed no change in relevant risk.

 

Based on these results what are the practical suggestions for HCPs around HRT and CVD?

In postmenopausal women:

  • Women who may be at risk from CHD could benefit from HRT use and treatmen could relieve cardiovascular symptoms
  • It can be beneficial to tailor dosage with age by starting women on standard dose when under the age of 50, lowering dose for women aged 50-60 years and using an ultra-low dosage for women older than 60 years.

In summary, evidence shows that MHT can be largely beneficial in reducing CHD, however this benefit is dependent both on age and time of initiation of HRT, with the largest benefit being seen in women starting treatment under the age of 60 and within 10 years of the onset of menopause.  

Now we’ve covered the link between HRT and CHD check back later to hear about the impact of HRT on memory in the symposium blog part 2!

References

1.       Lokkegaard et al. Maturitas 2006; 53: 226-33

2.       Schlipak et al. Circulation 2001; 104: 2300-09

3.       Tuomikoski et al. Obstet Gynecol 2014; 124: 947-53

4.       Boardman et al. Cochrane Database Syst Rev 2015