Even for Those on Statins, Healthy Levels of HDL Cholesterol Cut Cardiovascular Risk

Investigators in the Treating to New Targets (TNT) study cleared the path, once again, for better cardiovascular care. This time, their findings— published in the New England Journal of Medicine on September 27, 2007 — focused on the importance of heart patients’ high-density lipoprotein (HDL) cholesterol levels. HDL is considered the “good” cholesterol because it escorts extra lipids out of your blood vessels while low-density lipoprotein (LDL) is thought of as the “bad” cholesterol because it deposits excess cholesterol in your blood vessels, which harden into plaques and narrow the passageway for your blood. Studies have already shown that the amount of HDL cholesterol in your blood predicts your cardiovascular risk. Now, this analysis shows that it is worthwhile to pay attention to HDL cholesterol levels in heart patients who lower their LDL cholesterol levels with statin therapy.

Heart patients need more than statins
A statin-taker without much HDL cholesterol remains vulnerable to serious problems, this analysis showed:

The HDL cholesterol level helped predict the statin-takers’ risk of a major cardiovascular event—a stroke, heart attack (one that was not fatal and not due to a medical procedure), cardiac arrest (from which the patient was resuscitated), or death from coronary heart disease — even for those who reached the proven-protective “very low” LDL target, the researchers found.

To reach this conclusion, the TNT investigators analyzed their data on 9770 people. The subjects — men and women 35 to 75 years of age with established coronary disease — were followed for a median of 4.9 years. One group took a daily dose of 10 mg of atorvastatin; the other group took 80 mg per day. The subjects’ cholesterol levels were checked after 3 months. The researchers examined the relationship between the individuals’ levels of HDL cholesterol and the length of time to their first major cardiovascular event. They used various statistical analyses and factored in key variables, including sex, age, smoking status, body mass index, and other health factors.

Almost all the subjects were white, with a mean age of 60 years, and most were men. The subjects were grouped into 5 levels for this analysis, based on how low or high their HDL cholesterol level was at the 3-month measurement. The group with the highest HDL cholesterol levels showed less risk for a major cardiovascular event in the 5-year study period than those with the lowest levels. Those with more of HDL cholesterol were older, thinner, and more likely to be female than those with the lower levels, the researchers observed. The groups with the higher HDL cholesterol levels also had fewer current smokers and more individuals who never smoked. Diabetes was more common in those with the least amount of HDL cholesterol. The researchers acknowledged that they have financial ties to the sponsor and other drug companies and that factors their analysis did not consider may have been influential, such as waist circumference or insulin levels.

In a summary and comment in Journal Watch Cardiology, Harlan M Krumholz, MD, SM, urged healthcare providers to remain alert “to all known cardiovascular risk factors when using statins to treat patients with coronary artery disease.”

Implications
What are the experts likely to do with this information? The answer may be to expand their treatment focus, and look for new therapies.

What can you do with this information? Ask your health care provider about your cholesterol numbers:

Sources
S1
Barter P et al. HDL cholesterol, very low levels of LDL cholesterol, and cardiovascular events. 27 Sep 2007. New Engl J Med 357:1301-1310. On the Internet: http://www.nejm.org. Accessed 14 Jan 2008.

S2
High blood cholesterol. National Heart, Lung and Blood Institute. Feb 2006. On the Internet: http://www.nhlbi.nih.gov/health/dci/Diseases/Hbc/HBC_WhatIs.html. Accessed 16 Jan 2008.

S3
Krumholz HM. Does HDL matter when statins are working? (summary and comment). 26 Sep 2007. Journal Watch Cardiology. On the Internet: http://cardiology/jwatch.org. Accessed 14 Jan 2008.

S4
Low HDL cholesterol, even when LDL levels are low, is cardiovascular dynamite, new TNT analysis shows. 28 Sep 2007. Medscape Medical News. On the Internet: http://www.medscape.com. Accessed 14 Jan 2008.

S5
New analysis for TNT study highlights the importance of HDL cholesterol (report). HDL Forum. On the Internet: http://www.hdlforum.org/forum.html. Accessed 16 Jan 2008.