HRT - "Summary of Risk Ratios"

Given the amount of data we have presented, it would be useful to review the problematic aspects, the neutral outcomes, and the beneficial results from HRT.

Reasons to avoid HRT

Stroke

The meta-study results, together with a later WHI publication both indicate an increased risk of stroke. Risk Ratios range between 1.02 and 1.23, or anywhere between a 2% and 23% increase in stroke risk.

Pulmonary Embolism

The meta-study puts the Risk Ratio between 1.64 and 2.81 - a major increase in risk.

Breast Cancer

Both the meta-study and the "Million Women Study" (MWS) show that the risk increase is significant. Since the latter is an observational study, we have a right to suspect its results; never the less it agrees with WHI and the meta-study in its general trend of associating HRT with increased breast cancer risk. The meta-study puts the ratio between 1.23 and 1.35, and the MWS puts it between 1.58 and 1.75. An additonal study ("HABITS", The Lancet v363, p453, 2004) also concludes that the risk ratio is high. Either way, the risk is significant, and could be between a 23% increase and a 75% increase.

Dementia

Even though the meta-study indicates an advantage to using HRT for dementia prevention, the subsequent WHI results show that the risk ratio is between 1.19 and 2.60. The meta-study utilizes observational studies, whereas WHI is a randomized study. Consequently, we take its results rather than those of the meta-study.

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Last Modification - July 11, 2004