Any cardio protective effect of hormone replacement therapy may be inhibited if women are taking a particular type of non-steroidal anti-inflammatory pain killer, report researchers led by Garret FitzGerald from University of Pennsylvania.
The researchers examined the medical records of 1,673 women aged between 50 and 84 years from the UK's General Practice Research Database who had heart attacks or who died from coronary heart disease and compared them with 7,005 control women. Current use of hormone replacement therapy was associated with a significantly lower risk of heart attack than non-use; with an odds ratio of 0.78.
However, in women who used traditional nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, which variably inhibit both cyclooxygenase (COX)-1 and COX-2, at the same time as hormone replacement therapy, the chance of heart attack among this group o f women, as compared to nonusers of these NSAIDs and hormone replacement therapy, was 1.5, which was not significantly different.
There is conflicting evidence from previous work about whether hormone replacement therapy protects against heart disease in women. In addition, any beneficial effect of hormone replacement therapy on the heart might be counteracted by NSAIDs which inhibit COX-2. Inhibition of COX-2 prevents production of prostacyclin, which has a role in preventing blood clotting. As estrogen acts to increase production of prostacyclin; it is possible that the effect of hormone replacement therapy on the heart is counteracted by these NSAIDs.
The authors conclude that "these observations, based on small numbers, are provocative rather than conclusive and are not intended to guide clinical practice, but rather to prompt additional research." Ultimately determination of the clinical implications of these findings will need to be addressed in future trials.