Until yesterday it was generally believed that aspirin decreased heart attack risk and did little to primarily prevent stroke.But that wisdom was derived from trials in which the subjects were predominately men.The most recent data from the WHS seems to say the reverse is true in women-well not exactly. Overall no decrease in MI in women, except for those 65 or older in whom there was a 34 % decrease.Overall there was a 17 % decrease in stroke relative risk (RR).The changes in RR were small in general. The largest deviation from a RR of 1 was in the side effects side of the ledger with GI bleeding that required transfusion having a RR of 1.4.
If we consider magnitude of RR and biological plausibility as determinants of significance, the most significant finding of the trial may be that even low dose aspirin (100 mg every other day) can cause significant GI bleeding. This coupled with no decrease in heart attack risk ( which is largely why many women take aspirin and were told to take aspirin) and only a modest possible decrease in stroke risk (RR =0.83,p=0.04) leads me to question whether the current guidelines of the AHA and the PHSTF should still be -as the lawyers say-" good law". It seems reasonable to still be somewhat proactive for asa prophylaxis in women 65 and over who meet the risk assessment criteria of either group. Once again we see why guidelines are written on paper and not granite.Once again we see if we judge docs on whether they adhere to guidelines as opposed to being more current that the guidelines we convict them on faulty evidence.