MONDAY, Nov. 7, 2005 (HealthDay News) -- When older people are given statins, their levels of "good" HDL cholesterol may be a more important indicator of cardiac risk than levels of "bad" LDL cholesterol, new research suggests.
Prescribing a statin to people over 70 cut their risk of heart disease and death, no matter what their LDL levels were, Scottish researchers report in the Nov. 8 issue of Circulation.
But this benefit was especially strong among patients who entered the study with lower-than-normal levels of HDL cholesterol, the study found.
"This was quite a surprise," said study author Christopher J. Packard, a professor of vascular biochemistry at the University of Glasgow. "We did not expect the benefits of statin therapy to vary according to starting HDL level. Also, unlike statin studies in younger persons, LDL was not what mattered [here]."
A link between low HDL levels and arterial inflammation, which has emerged as a risk factor for heart disease, might explain the results, Packard said.
"My working hypothesis is that statins block inflammation, and thereby reduce the deleterious effects of low HDL," he said.
Another possibility is that statin treatment affected the balance between the build-up of fatty deposits in the arteries, which is mediated by LDL cholesterol, and the removal of those deposits, which is mediated by HDL cholesterol, the researchers said.
The report used data from a study of more than 5,800 men and women aged 70 to 82. All had a history of cardiovascular problems such as heart attack and stroke, or were at high risk for these events due to conditions such as high blood pressure, diabetes or smoking. Half the participants got a daily dose of a statin, while the others got a placebo.
Patients who entered the study with low blood levels of HDL -- below 45 milligrams per deciliter -- and then took the statin were one-third less likely to have a heart attack or die of heart disease in the following 3.2 years, compared to those who did not receive the statin. In contrast, patients who entered the study with high blood levels of HDL did not seem to receive any benefit from the statin.
The researchers also found no relation between initial patient blood levels of "bad" LDL cholesterol and statin-related declines in heart risk over the course of the study.
More studies are needed to determine whether statins' effect on inflammation is responsible for their close relationship with HDL, the researchers said. According to Packard, learning the exact reason for the reduction in risk could help patients.
"If statin therapy could be targeted to at-risk elderly with low HDL levels who would benefit most, fewer people would have to be treated," he said.
The study used a single drug, pravastatin (Pravachol), but the results probably apply to all statins, Packard said.
The report could be an indicator of a major shift in cholesterol treatment, said Dr. Steven Nissen, a cardiologist at the Cleveland Clinic.
"What LDL was in the 1990s, HDL will be in the new millenium," Nissen said.
He has a personal stake in that opinion. Nissen is working with a pharmaceutical company on the development of a drug aimed at lowering HDL, based on the view that "it looks like the greatest benefit for patients who get statins aren't those with the highest levels of LDL, but those with the lowest levels of HDL."
But Nissen said he remains cautious about the new report, in part because the study was not designed to detect this LDL-HDL difference. New studies are needed to prove the point, Nissen said. He is in the midst of such a study, using the new HDL-focused drug.
"I should have the results at the American Heart Association meeting next year," he said.
For more on statins, head to the American Heart Association.