Wednesday, January 11, 2012


I remember speaking at a public forum on aspirin back in the 80s on the role of low dose aspirin in preventing heart attacks. The audience was thrilled and convinced, and low dose aspirin was launched bigtime into the Malaysian market. That marketing blitz was sponsored by Rekitt Coleman ( at that time ), and they were launching cardiprin.
Well much water has gone under the bridge, and much mor medical evidence has emerged since then on the good, and bad of low dose aspirin.
Now we are certain that low dose aspirin is a good anti-platelet agent, and has an established role in preventing heart attacks ( fatal and non-fatal ) in patients withe established CAD. It has a definite role in preventing stent thrombosis both in bare metal stents and also drug eluting stents.
It does have a role in stroke prevention especially in patients with chronic atrial fibrillation and low CHADs score. It probably have a role in prevention of Ca Colon, especially in the context of Polyposis Coli.
well, if low dose aspirin is so useful, a help for all ills, why don't we all take it or better still, put some in our drinking water, just as we add some chlorine.
well the issue is the side effects. When I spoke in the 80s, we thought that normal dose aspirin, 365 mg for fever, and pain, increases the risk of GI bleed and worse still intra-cranial bleed. So the early studies then showed that low dose aspirin of 100mg daily ( a third the dose ) will have less bleed. That is true. But there still is, and that raises the issue of safety. How safe is low dose aspirin.
well, the latest issue of the Archives of Internal Medicine carried a piece of work by Prof Kausik ray et all, from St Georges Hospital, University of London. They followed up 102,621 patients who were on low dose aspirin to prevent heart attacks. These were patients who had no history of previous heart disease ( primary prevention of heart attack ). These patients were followed up for 6 years. They found that after 6 years of low dose aspirin, there was a 20 % reduction in the incidence of non fatal heart attacks. No difference in the incidence of fatal heart attacks. There was a price. There was a 30% increase incidence of potentially life threatening bleed including intra-cranial hemorrhage. What that means is that for every 160 patients treated with low dose aspirin for 6 years, you prevent one non fatal heart attack. BUT for every 73 patients in the same group, you may get one troublesome bleed.
So the balance of evidence must be that we should not use low dose aspirin to prevent heart attacks in patients without previous CAD, as it may do more harm than good.
That seem to be the consensus presently. Except for particular subsets like Diabetics with diffuse atherosclerosis, we would no longer use low dose aspirin as a means of primary prevention. There is certainly no role to give low dose aspirin to all and sundry.
As for ca Colon prevention, I think the jury is still out on that. We have to wait and see. Certainly, if I have Polyposis Coli and also diabetes, I may be tempted to taking a low dose aspirin.

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