Aspirin vs statins
Many people take aspirin to prevent heart attacks. Aspirin thins the blood and reduces the risk of blood clots. It also reduces inflammation, which explains why it relieves pain. Scientific studies have shown aspirin provides some prevention, although experts suspect this benefit derives from the blood thinning properties rather than the anti-inflammation properties. C-Reactive Protein in the blood is a marker diagnosticians can use to assess inflammation of the cardiovascular system, and aspirin does affect the CRP levels, but the that probably has little to do with its protective effects, according to current thinking.
The official story on statins is that they work by reducing the production of cholesterol in the liver. While there is some skepticism (some experts believe statins work primarily through anti-inflammation), the reduction of CRP due to statins may be indirect – a function of the lower cholesterol levels in the bloodstream.
So aspirin and statins work in different ways. Many people have doctor's orders to take both. The U.S. Preventative Task Force recommends low doses of asprin for those between 50 and 60 to protect against heart disease and cancer. However, it is not true that one can be substituted for the other. Some experts have proposed development of a polypill that would combine aspirin and a statin and other medications to reduce the risk of cardiovascular disease.
The joint use of aspirin and a statin can reduce CRP, especially in people who use aspirin for over 5 years. In patients with kidney disease the cardioprotective effect of a statin and aspirin combination seems to be reduced.
Note that patient attitudes toward the two drugs are likely different because one is a prescription medication and the other is purchased over the counter. (This may change if statins are ever approved for over-the-counter sale.) Whether people are more likely to take the prescription drug or the over-the-counter one over the long run is not clear. A British study found 60% of patients told to take aspirin kept with it for the long run (5 years), while 64.5% of statin patients maintained the regimen, and 76% of those who were told to take both.