The more than 18 million American patients who receive statins to help them lower their "bad" LDL cholesterol may be getting an additional benefit -- a boost to their "good" HDL cholesterol.
The hope is that treatments to raise HDL cholesterol could one day be paired with statins to help patients with heart and artery disease.
The finding is also a vindication for many cardiologists who, despite the recent failure of one HDL-raising drug in clinical trials, continue to hold out hope for such therapies.
Researchers at the Cleveland Clinic analyzed four other studies and report that improvements in HDL levels are linked to a reduced risk of blocked arteries. Moreover, the authors note in the study, "even when HDL did not go up by very much, patients saw substantial improvement in blocked arteries."
Statins -- a class of drugs that includes Lipitor, Crestor and Zocor -- are the No. 1 selling drugs in the country today.
They are primarily used to lower levels of LDL cholesterol, thus limiting the formation of artery-blocking plaque.
But researchers found they may also raise HDL levels between 5 and 10 percent -- perhaps providing the little extra boost needed to further improve patients' chances of avoiding artery blockage.
"We've had statin drugs for 15 years, and we've known that they are very effective in lowering LDL cholesterol," says lead study author Stephen Nicholls of the department of cardiovascular medicine at Cleveland Clinic. "But we also had evidence that they worked in different ways."
Nicholls says the prospect that even a modest increase in HDL levels can improve a patient's chances of avoiding heart disease is good news.
"The conventional thought was that a 5 to 10 percent increase probably didn't contribute too much in terms of clinical benefits," Nicholls says.
"But what we found was that this effect had a marked benefit in these patients."
Moreover, Nicholls and his colleagues also found that those patients who experienced the most significant boosts in their HDL levels actually experienced a regression in plaque -- meaning the higher HDL levels "cleaned out" their arteries to a certain extent.
"This, in particular, highlights the importance of increased HDL, even in small degrees, in removing plaque from the arteries and preventing heart disease," Nicholls says.
But while most heart experts agree that raising HDL could be a promising approach to treating heart disease, not all are convinced that such modest increases could be responsible for the positive effects.
"HDL raising with a statin is so modest -- generally 5 to 10 percent -- that it is hard for the individual to even notice it, and it requires large studies like this to see statistically significant effects," says Dr. Daniel Rader, director of preventive cardiovascular medicine at the University of Pennsylvania.
And some heart disease experts say other factors might be at play.
"It is hard to be certain that the contribution to plaque regression … is really from HDL raising," says Dr. James Cleeman, senior medical officer at the National Heart, Lung and Blood Institute.
"This study lends support to the hypothesis that even modest raising of HDL levels lowers heart risk, but it is not definitive," says Dr. Lori Mosca, director of preventive cardiology at New York-Presbyterian Hospital.