10th July 2002

Women's Health Institute trial of HRT reveals relatively little new information

Despite the media outcry on the early stopping of the Women's Health Institute (WHI) trial of HRT, the findings reveal relatively little new information but largely confirm existing knowledge. 

The principal reasons for prescribing HRT continue to be relief of menopausal symptoms and the prevention and treatment of osteoporosis.  The WHI study largely confirms established knowledge of benefits (fracture prevention and reduction in incidence of colorectal cancer) and adverse effects (increased risk of breast cancer and venous thromboembolic disease). 

Essentially the study finds that HRT does not protect against Cardiovascular Disease (CVD).  Protection against CVD had been suggested by previous evidence but HRT has never been licensed for this reason.  

Although the percentage differences in disease rates between HRT users and the control group in the study appear large they represent a small number of actual cases, because the actual disease rates were low in both groups.  For example the study showed a difference of 29% in Coronary Heart Disease (CHD) events between the two groups but the actual numbers of women who suffered CHD events were 37 per 10,000 in the HRT group as opposed to 30 per 10,000 in the control group.

The death rate was no higher in women taking HRT as compared with women in the control group.

GPs currently assess potential risks and benefits in each woman before prescribing HRT and regularly reassess the situation at each follow-up visit.

This paper changes nothing for the majority of Irish HRT users who take it for a relatively short period of time to relieve menopausal symptoms.  Women who are already taking HRT are in no immediate danger and can continue using their current preparation until they are due for review by their prescribing doctor. 

Women who choose to stop their HRT immediately will do themselves no harm in the short term but should discuss their long-term risks of osteoporosis and the treatments available to them with their doctor.  Women should not consider starting or continuing HRT if the only reason is a risk of cardiovascular disease.