In a recent edition of Lancet, investigators from the UK report that lowering LDL cholesterol levels with statin drugs significantly reduces the risk of cardiovascular events such as heart attack, invasive coronary artery procedures, and stroke. Furthermore, the reduction in risk was not related to the absolute LDL levels, but instead to the reduction in LDL levels.
The investigators reached this conclusion by performing a meta-analysis of 14 large clinical trials in which 90,000 patients were randomized to either statin therapy or placebo. They found that reducing LDL cholesterol levels by 1 mmol/L lowers the 5-year risk of cardiovascular events by 21%. (Note: this unit of measure - mmol/L - is used commonly in Britain instead of mg/dL, which is used in the United States. One mmol/L equals 39 mg/dL.) This benefit was seen whatever the beginning or ending LDL levels.
Importantly, it appears from this analysis that the lowering of LDL cholesterol itself - rather than either the baseline or the ending LDL level - was the important factor. Reducing LDL cholesterol levels with statins, whatever those levels may have been in absolute terms, significantly reduced cardiovascular risk.
DrRich comments:
This intriguing study raises the question as to whether something might be going on with statin drugs besides the lowering of LDL cholesterol. Even when baseline cholesterol levels were not particularly elevated, statin drugs seemed to reduce risk. There are at least 2 possible explanations for this observation. First, this may be evidence that, where LDL cholesterol is concerned, the lower the better. Second, it may be evidence that some of the other recently-documented effects of statin drugs - in particular, their ability to reduce C-reactive protein (CRP) - may be playing a significant role in risk reduction.
In either case, this report lends further support to recent guidelines suggesting that LDL cholesterol levels be pushed to below 100 mg/dL in high risk patients, and to 70 mg/dL in the highest-risk patients. Achieving such low levels almost always requires the use of statin drugs.
