The Cholesterol Paradox

http://www.healthcentral.com/news/Ne....cfm?id=516315

The Cholesterol Paradox

A study finds higher levels may actually benefit people with heart
failure.

By Andrew Conaway

HealthDay Reporter

TUESDAY, Dec. 2 (HealthDayNews) -- A new study turns common sense on its
head by suggesting high cholesterol levels may actually help people with
heart failure.

Despite the fact that high blood cholesterol has been linked to
increased risk for ailments such as coronary vascular disease and
blocked arteries, especially in combination with other risk factors, the
finding that higher levels may help this group have researchers
scratching their heads.

"On the face of it, the result seems quite surprising, given the strong
association between cholesterol and vascular disease. However, we have
been developing for some time the notion that heart failure is a
metabolically stressful illness," says Dr. Andrew L. Clark of Castle
Hill Hospital and the University of Hull in England. Clark is co-author
of the study, which appears in the Dec. 3 issue of the Journal of the
American College of Cardiology.

"A high cholesterol level can be seen as good in that it indicates a
greater reserve to deal with metabolic stresses. And this is supported
by some of the other studies. . . showing a greater survival with
increasing body weight in heart failure and following heart surgery,"
Clark adds.

Researchers from Castle Hill Hospital, along with colleagues in London
and Berlin, studied 417 patients with chronic heart failure and found
the chance of survival increased 25 percent for each
39-milligram-per-deciliter (mg/dl) increment in total cholesterol.

On average, patients with a total cholesterol level of 232 mg/dl had a
25 percent higher survival rate than heart failure patients with a total
cholesterol level of 193 mg/dl. Experts say a total cholesterol figure
under 200 mg/dl is desirable.

Although the results of this study go against the usual "lower
cholesterol is better" advice, they reinforce findings in several
previous studies that linked lower cholesterol with poorer prognosis in
heart failure patients, the study says.

Clark says two hypotheses may explain the paradoxical relationship.

"Lipoproteins are good at absorbing bacterial endotoxin. An intriguing
notion is that the reason for the immune system activation seen in heart
failure patients is related to bowel wall edema, allowing bacterial
translocation into the body. It may be that lipoproteins mediate a
beneficial effect by mopping up any bacterial proteins before they cause
immune system activation," he says. "I tend to like the lipoprotein
idea."

But he cautions on the use of cholesterol-lower statins for chronic
heart failure patients.

"If [health professionals] are using cholesterol-lowering statins, they
are doing that without evidence that what they are doing is correct.
What we say to them is get those patients, those with chronic heart
failure, to clinical trials so it can be studied further," Clark says.

However, some caution that lower cholesterol may not necessarily be the
cause of the higher mortality in heart failure patients, but may be a
indicator of other factors that might be linked.

Dr. Robert Doughty, a research fellow at the University of Auckland in
New Zealand, who was not connected with the study but reviewed the data,
emphasized the results cannot determine that low cholesterol was the
cause of worse outcomes in the heart failure patients.

"We have to be careful about this data. Don't get me wrong, and it is
very interesting data," Doughty says. "But we should not automatically
extrapolate this group of patients who may be at the endgame of their
disease, and don't forget -- chronic heart failure patients are at the
end stages of their disease."

"Just because there is association doesn't mean there is causality. This
study is important, but there is more work needed to be done for that
group which has progressed further along with heart failure due to
coronary heart disease," he adds.