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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.
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