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The American College of Cardiology/American Heart Association published their latest cholesterol management guideline last month. It is a complete change of the prior American guidelines that aim at a particular cholesterol target.
First of all, it recommends treatment for the 4 groups of patients:
1. All who already have heart disease, stroke or peripheral blood vessel disease (“cardiovascular diseases”)
2. Everyone with diabetes between 40-75 years of age
3. Those with an LDL (bad) cholesterol of 190 mg/dl (5.0 mmol/l) or more
4. Those with a calculated 10-year risk of cardiovascular disease of 7.5% or more.
Secondly, they suggest using only statins, and no other cholesterol-lowering medication.
Thirdly, they recommend stopping the routine monitoring of cholesterol levels after treatment, because of the lack of evidence.
Lastly, they place far less emphasis on additional screening tests such as hsCRP, a mark of inflammation in the body and cardiovascular risk
Since then Dr Nancy Cook and Dr Paul Ridker had published an article in the New York Times that call into question the calculator used, unusally before their critique paper in the journal Lancet has been published. Cook and Ridker pointed out that the calculator overestimates the cardiovascular risk in their own data set of patient population. Dr David Goff, co-chair of the guideline committee, explained that the population set used by Cook and Ridker are more recent and those patients have reduced risk probably because they are volunteers, and might have already taken statins and so their risk became lower. Interestingly, Goff was also puzzled by Ridker’s lack of comment in 2012 when the guidelines were sent to Ridker, and revealed that Ridker’s suggestion to use hsCRP in the risk calculation was rejected. Ridker receives royalties as co-holder of patent on hsCRP, which is a blood test used for risk-stratification for cardiovascular risk.
Hmm. I had not seen a guideline critique being so personal before. Previously, lead authors exchange disagreements in the journals, in an usually courteous manner.
The American Association of Clinical Endocrinologists had just rejected the guideline. They disagree with removing the cholesterol targets, the out-dated risk calculator, and the omission of medication other than statins in lowering cardiovascular risk.
Do we doctors agree on anything now about cholesterol? Well there are:
1. High cholesterol is associated with blood vessel blockage (atherosclerosis), heart attacks and stroke.
2. Lowering cholesterol generally lowers that risk. Most studies were done on statins, but other studies on other medication, such as niacin, fibrates and Vytorin, had also shown benefits before.
3. The relative benefits are rather constant. So patients with high risk benefit more. For example, if a patient has a 50% risk of having a heart attack in 10 years, lowering the cholesterol can reduce the risk to 25-30%. So 1 in 4 patients are saved. But for a low risk person with 1% risk of having a heart attack in 10 years, lowering the cholesterol reduce the risk by 0.4-0.5%. So 200 people needs to be treated before one is saved.
4. All cholesterol-lowering medication has a small risk of side effects. Muscle ache, increased liver enzymes, and diabetes are the commonest.
Ultimately, it is best that you discuss with your doctor whether you need treatment. You should ask about the benefits and the risks of taking the drug.