OmniBlog

We need low-density lipoprotein (LDL) to transport cholesterol (and triglycerides) from liver to the peripheral tissues. Traditionally, LDL is also called bad cholesterol as high levels of this lipoprotein may mean increased transport of cholesterol towards arteries, causing plaques and coronary heart disease (CHD) eventually.

When we detect high levels of LDL in our patients, we attempt to reduce the levels to an individualized target based on the patient's (cardiovascular) risk profile.

This is the recommendation on therapeutic goals for LDL:

Risk Profile	LDL Goal
0-1 risk factor	<160 mg/dL	<4.1 mmol/L
2 or more risk factors	<130 mg/dL	<3.3 mmol/L
CHD or CHD equivalents*	<100 mg/dL	<2.6 mmol/L

* One of the important CHD equivalents in Diabetes

In addition to these goal levels, another recommendation was to reduce LDL to a level below 70 mg/dL (1.81 mmol/L) in these situations:

• primary prevention in "very high risk" patients (1), and
• further goal after achieving <100 mg/dL in secondary prevention for all patients (2)

This recommendation to lower LDL "below 70" was not so well received. Studies (3, 4) published in the Annals of Internal Medicine criticised this as "not based on available evidence".

A scientific publication from Israel (5) claimed increased risk of sepsis and malignancies in patients with LDL below 70 mg/dL.

The wikipedia page on LDL (6) , to which I have also contributed, ends with

The feasibility of these figures has been questioned by sceptics, claiming that many members of the AHA and NIH are heavily associated with pharmaceutical companies giving them bias towards lowering cholesterol levels and such guidelines giving rise to increased use of cholesterol lowering medicine such as statins.

A more balanced view was recommended in a paper in the American Journal of Cardiology (7) which stated:

In men, elevated LDL need not be treated aggressively if the total/HDL cholesterol ratio is low. Conversely, modest elevations of LDL may warrant more aggressive treatment if the ratio is high.

In women, the ratio is also a good CHD predictor, but a combination of a high ratio accompanied by high LDL cholesterol may warrant more aggressive therapy.

Conclusion: How Low?

There are conflicting reports on this question. More evidence may hopefully be available soon. In the meanwhile, it is better to be modest and not push the LDL too low, as it is still a relatively unknown zone.

Remember, primum non nocere (first, do no harm)?

PS: This topic is somewhat similar to my earlier post "Iatrogenic mass hypochondria".