Friday, August 03, 2018

Aspirin and Body Weight

Low dose aspirin has been shown to reduce cardiovascular events but the observed effect may vary by weight. In fact, in one of our studies, we have shown that not only obese individuals had greater baseline platelet reactivity, they also had greater residual platelet reactivity after low-dose aspirin therapy. Comparing obese and nonobese individuals after aspirin therapy, results for aggregometry to collagen were 6.7 vs 6.1 ohms, P=.008; aggregometry to adenosine diphosphate were 13.1 vs 11.8 ohms,P<.0001; aggregometry to arachidonic acid (AA) were 4.9% vs 8.3% nonzero aggregation, P=.002; urinary excretion of 11-dehydro-thromboxane B2 (Tx-M) were 4.9% vs 8.3% nonzero aggregation, P=.002; and aspirin resistance were 26.% vs 20.5%, P=.002; respectively.

Now an individual-patient meta-analysis of primary prevention randomized controlled trials with low-dose aspirin have shown that clinical outcomes are also different in patients with weight>70Kg than in patients with weight<70Kg. On the other hand, when a higher dose of aspirin was examined, individuals with weight>70Kg obtained clinical benefits. Clinical benefits were not limited to cardiovascular outcomes but also included colorectal outcomes.

An obvious implication of such studies is that individuals with weight>70Kg should take perhaps more than one baby aspirin to receive benefit from aspirin.

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