Is HRT a cardiovascular risk for older women

Observational studies have usually shown a benefit of HRT for both primary and secondary prevention of CHD in postmenopausal women. However, randomised clinical trials of HRT have not shown any significant benefit on CHD in older women or in those with established disease. But in women initiating HRT at a younger age and closer to the onset of menopause, more recent studies have shown a benefit on CHD events, atheroma progression, and CHD mortality. Whilst these benefits in younger women have not been shown in older women, HRT has not been shown to cause CHD harm. In the Women's Health Initiative (WHI) combined phases (intervention and cumulative follow-up), there was no significant increase in either CHD or stroke in those women initiating estrogen-progestogen or estrogen alone HRT above age 60 years compared with placebo. This is in accordance with large meta-analyses of randomised clinical trials of HRT effects on CHD events or mortality where no significant benefit, but also no harm, is seen in women initiating HRT above age 60 years or beyond 10 years after menopause. The lack of benefit in older women may well be the result of the use of inappropriately high starting doses of HRT. Adverse cardiovascular effects of estrogen, such as coagulation activation and adverse vascular remodelling, are dose-dependent effects, and could be avoided or minimised with lower starting doses. The ELITE study showed that the benefit of HRT seen in reducing atheroma progression in women initiating HRT soon after menopause was not seen in those initiating at a later age. But whilst there may be little benefit of HRT on established atheroma, there is evidence that older and diseased arteries can still respond favourably to estrogen in terms of function. HRT use in older women may not cause cardiovascular harm providing appropriately low starting doses are used and may even provide some benefit.