I'm not crazy: aspirin for everyone?

I sometimes start to wonder if I’m crazy when conventional docs continually and persistently do things that I’m sure are a bad idea. Are they all practicing bad medicine or am I crazy? It’s nice when I’m reassured that I was right all along.
This time, it’s about aspirin. Whenever anyone over the age of 35 goes into a doctor’s office, it seems like the doctors routinely put them on an aspirin a day. The dose of aspirin depends on the doctor’s specialty: primary care docs recommend 81mg and cardiologists want people on 325mg or more.
Ostensibly, the aspirin is to reduce the risk of heart attacks. It reduces the stickiness of platelets (which make blood clot), making them less likely to clump and clog up arteries and cause heart attacks and ischemic strokes (caused by a clot).
However, aspirin is (like most drugs) not an entirely benign substance. It can cause bleeds in the stomach and intestine, which can be worsened by the anti-clotting actions of it. In addition, it can increase the risk of any type of bleeding, particularly hemorrhagic strokes (caused by a bleed rather than a clot: less common but worse).
Recent research has demonstrated that while aspirin does reduce the risk of another heart attack in people who have had one, it isn’t so impressive in people who have never had a heart attack. In particular, the only people who haven’t had a heart attack yet who should be candidates for daily aspirin use are people over 45 (men) or 55 (women) who are already at high risk of a heart attack and don’t have risk of bleeding (BP is close to normal and not at risk for falls).
Now the big question: if some should get aspirin, what dose should they get? Once again, the
primary care docs provide better care than specialists: 81mg provides better risk reduction and less increase in risk than 325mg. In fact, it appears that higher doses of aspirin might blunt the anti-platelet effects in addition to increasing the risks of adverse events (however it appears that cardiologists might not be reading their own journals like Chest).
So, how effective is it? Well, 119 high-risk men under 60 would need to take aspirin for 5 years to prevent one heart attack. Over those 5 years, there is a little more than a 1 in 3 chance that someone in that group will have a major intestinal bleed because of the aspirin. Put another way, if we took 1000 men with a 6% 10-year risk of hart attack and gave them aspirin for 10 years, we will have prevented 19 heart attacks (dropping the number from 60 to 41), caused 8 major bleeds and 1 hemorrhagic stroke. Men can
look up their risk/benefit ratio here.
In women, the benefit is less impressive: the chance of preventing a stroke is less and isn’t that different from the chance of causing a bleed. Women can
look up the specific risk/benefit ratios here.
However, if you are
having a heart attack, one of the best things you can do (in addition to calling 9-1-1) is chew up and swallow an aspirin. I’d still make the phone call first, though.