Aspirin Therapy For Primary Prevention of Heart Diseases – The Gender Effect.
There is plenty of evidence indicating that aspirin therapy reduces mortality among people already had preexisting cardiovascular diseases. There is also plenty of evidence indicating that aspirin is also effective in the context of primary prevention. However, recent studies seem to suggest that the effectiveness of aspirin in preventing cardiovascular diseases is gender-specific.
The Women’s Health Study reported that aspirin decreased the risk of stroke without affecting the risk of myocardial infarction (MI) or vascular death. This contradicts the findings for men, whose rates of MIs, and vascular mortality are substantially reduced by aspirin.
Berger et al, (2006) conducted a gender-specific meta-analysis of aspirin in the primary prevention of cardiovascular disease. The study was published in Journal of American Medical Association.
Berger et al. (2006) found that the rate of MI was similar among both women receiving aspirin and women receiving control treatment/placebo (the odd ratio is 1.01). On the other hand, aspirin therapy leads to a 32% reduction in the risk of MI.
With regarding to stroke, aspirin therapy leads to a 17% reduction in the risk of stroke in women, but increases risk of stroke in men. More specifically, aspirin reduces ischemic stroke by 24% but has no effects on hemorrhagic stroke in women. With men, the effects are reversed. Aspirin increases hemorrhagic stroke by 69% in men but has no effects on ischemic stroke. Interestingly, despite reduced risks of having stroke and MI, aspirin therapy does not affect the rate of cardiovascular deaths in both men and women.
The potential mechanisms underlying the gender-specific differences in aspirin’s cardio protection are:
· Aspirin metabolism is different between men and women. For the same dose, the pharmacological effects of aspirin are stronger in men than in women
· Women are more likely to have stroke than MI, hence the effects on stroke are more pronounced
· Women are more likely to develop aspirin resistance than men
The findings of the above meta-analysis suggested that guidelines regarding aspirin therapy must be developed separately for men and women (Loomba and Arora, 2008).
Review: Prevention of coronary heart disease in women Rohit Seth Loomba and Arora Therapeutic Advances in Cardiovascular Disease 2008;2:321-327.
Ridker PM, Cook NR, Lee IM, et al. A randomized trial of low-dose aspirin in the primary prevention of cardiovascular disease in women. N Engl J Med. 2005;352:1293-1304.
Berger JS, Roncaglioni MC, Avanzini F, et al. Aspirin for the primary prevention of cardiovascular events in women and men: a sex-specific meta-analysis of randomized controlled trials. JAMA. 2006;295:306-313.