WEDNESDAY, Jan. 19 (HealthDay News) -- Stroke rates have increased among people with HIV in recent years while declining in the U.S. population at large, new research shows, raising the possibility that treatments for the AIDS-causing virus may put these patients at higher risk for cardiovascular trouble.

There's no direct proof linking the medications to the higher stroke rate, but previous research has suggested that HIV drugs can boost cholesterol and triglyceride levels, both of which contribute to stroke risk.

"Until we have a better idea what's happening, this is a call or reminder to clinicians to be cognizant of these risk factors for stroke in these HIV patients," said study author Dr. Bruce Ovbiagele, a neuroscience professor at the University of California, San Diego.

For their study, published online Jan. 19 in the journal Neurology, Ovbiagele and colleagues examined a database of hospitalizations for stroke from 1997, when a new generation of AIDS drugs was in its early days of use, through 2006.

They found that while overall hospitalizations for stroke fell by 7 percent, the number of stroke hospitalizations in HIV-infected people rose by 60 percent in 2006. (The researchers adjusted their numbers to account for factors such as age and gender.)

The researchers also looked at the two kinds of stroke -- ischemic (when a blood vessel is blocked) and hemorrhagic (when a blood vessel bursts). There was no change in the percentage of hemorrhagic stroke patients who were HIV-positive, but the rate went up from 0.08 percent to .18 percent -- more than doubling -- among HIV patients who had ischemic strokes.

The latter number suggests, but doesn't prove, that more HIV patients are suffering from blockages in their blood vessels. Some previous research has suggested that HIV patients have higher levels of heart attacks, which also occur when vessels clog up.

"We know that many of the drugs that are used for AIDS treatment have metabolic complications, which include the addition of belly fat and an increase in serum triglycerides," Ovbiagele said. Both increase the risk of heart problems.

It's possible that HIV patients are living longer and simply getting to the age at which strokes are more common among all people, said Ovbiagele, who was at the University of California at Los Angeles, when the research was conducted. But the study also found that HIV patients had strokes earlier, on average, than other people.

Overall, the risk that an HIV patient will have a stroke remains low. However, patients who are on AIDS drugs should be aware that stroke is "highly preventable," Ovbiagele said, and they should work with their doctors to keep their weight and cholesterol levels under control.

Dr. Alejandro A. Rabinstein, a professor of neurology at the Mayo Clinic in Rochester, Minn., said that even while the link between AIDS medications and stroke isn't proven, HIV patients should go on low-fat, low-sodium diets and be monitored for high blood pressure and other risk factors.

However, he said, strokes will remain rare among patients on HIV drugs. "The risk may be increased, but it is overall a small risk," he said.

More information

For more about AIDS, see the U.S. National Library of Medicine.