Wednesday, October 26, 2011

Does Raising Your HDL Cholesterol Really Help?


October 26th, 2011  
written by Michael O'Leary
Dr. Gregory Nichols
Type 2 diabetics know they have a significantly higher risk for coronary artery disease that can lead to heart attacks and hospitalization. There has been tremendous progress in heading off these heart attacks using LDL cholesterol-lowering medications. The evidence is growing, however, that raising HDL cholesterol may double the benefits in both lowering LDL cholesterol and reducing hospitalizations due to cardiovascular disease.
That’s the finding of a large study conducted by Kaiser Permanente Center for Health Research in Portland, Ore. as reported by MedPage Today. The researchers found that for every increase of 5 milligrams of HDL cholesterol per deciliter (mg/dL) of blood there was a 6 percent reduction in hospitalization due to cardiovascular disease. (Link to published site)

The study was led by Dr. Gregory Nichols of Kaiser, and the study was published online in the American Journal of Cardiology. The researchers looked back at a group of 30,067 members of the Kaiser Permanente Northwest and Georgia regions. All patients had type 2 diabetes and had at least two HDL cholesterol measurements between 2001 and 2006.
The investigators examined clinical data on the patients through 2009 to determine whether their HDL cholesterol levels affected hospitalizations due to cardiovascular events, such as chest pain, or heart attacks. They categorized the patients into three groups, those who raised their HDL cholesterol levels by 6.5 mg/dL or more, those who decreased their HDL cholesterol levels by 6.5 mg/dL or more, and those whose HDL levels didn’t change over the study period.
At the end of the study, 61 percent of the patients had no change in HDL cholesterol levels, 21.6 percent increased their HDL cholesterol by 6.5 mg/dL or more, and 17 percent decreased their HDL levels by that much.
A total of 3,023 patients (10.1 percent) had cardiovascular-related hospitalizations during the follow-up period. After adjusting for multiple factors, they found that a 6.5 mg/dL or more decrease in HDL was associated with an 11 percent increased chance of heart attack or hospitalization due to cardiovascular disease, whereas a 6.5 mg/dL increase in HDL reduced those chances by 8 percent, as compared with individuals whose HDL levels remained about the same as at the start of the study.
This study’s main limitation is that it is an observational study, meaning the researchers only observed what happened over time in the three groups of type 2 diabetes patients. Consequently, there is no way to know precisely if the increased HDL levels actually caused the lower hospitalization rate in that group, and visa versa.
Unfortunately, so far the drugs that raise HDL cholesterol have largely been less than successful, but the search for a drug that works without unacceptable side effects continue. The most promising appears to be anacetrapib, which is being studied in a couple of trials in Europe.  In a presentation of early results of the DEFINE trial showed that anacetrapib increased HDL levels by an average of 138 percent and lowered LDL cholesterol by 39.8 percent compared to placebo. In addition the drug did not have any of the safety problems that ended trials for torcetrapib, an earlier drug aimed at raising HDL cholesterol.
For their part, the Kaiser Permanente researchers are optimistic about the prospects of targeting HDL as a strategy for reducing cardiovascular disease in people with type 2 diabetes.
“Despite these limitations, we have concluded that the changes in HDL cholesterol are associated with changes in the risk of cardiovascular disease hospitalizations,” the authors wrote in conclusion. “Additional study is needed to understand the role of improving HDL cholesterol in a multifactoral prevention strategy."

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