HIV infection may increase the risk of heart disease, research suggests.
Researchers at the University of California in San Francisco found HIV patients had higher rates of atherosclerosis, or clogged arteries.
The condition also progressed more quickly in HIV positive people.
Writing in Circulation: the Journal of the American Heart Association, they said HIV patients should be treated for high blood pressure and cholesterol.
Atherosclerosis is a build up of fatty substances, such as cholesterol and calcium, which collect as deposits called plaques on the inner lining of an artery.
Pieces can break off the plaques and lodge in the artery causing tissue damage, and triggering the development of potentially deadly blood clots.
Dr Priscilla Hsue, assistant professor of medicine at the University of California and colleagues studied 148 HIV patients, with an average age of 45, who had been infected for around 11 years.
They compared them to a group of 63 non-infected people, of a similar age group.
The HIV patients had all been taking protease inhibitors - a common form of medication used to control the infection - for over three years.
Using ultrasound, researchers measured the thickness of muscle layers in the wall of carotid arteries in the neck, which supply blood to the brain.
They found artery thickness was on average 23% wider in people with HIV infection.
Some 45% of HIV patients showed signs of a buildup of carotid plaque, compared to only 24% in the control group.
Dr Hsue said “Our findings suggest that it would be reasonable to consider HIV infection a cardiac risk factor.
“Other risk factors, such as High cholesterol and high blood pressure, need to be aggressively treated in HIV patients - even if it means changes in their HIV medications to control cholesterol levels.”
The researchers found the level of atherosclerosis in HIV patients was linked to factors such as age, high blood pressure and smoking.
Professor Brian Gazzard, an expert in HIV at Chelsea and Westminster Hospital said it is possible that atherosclerosis was a side effect of HIV treatment.
“The drugs people take for HIV cause a change in lipid metabolism, which can increase the level of cholesterol and fats that are contained in the artery,” he told BBC News Online.
But he said many people believe the infection itself could be linked to atherosclerosis and heart disease.
“Some infections can be an important precipatory factor in heart disease, as they can directly infect the arteries.”
However, he added that the risks of heart disease among HIV patients are too small to outweigh the benefits of HIV medication.
He said it is also hard to separate the real cause of heart disease among HIV patients, when there are so many influencing factors.
“One factor is many HIV patients smoke, and until recently, many had no incentive to give up.
“Now with increased life expectancy rates for HIV positive people, we need to help them stop smoking.”
Professor Gazzard said a larger study would be needed to provide solid evidence.
“That’s a very tiny number to make definitive conclusions from.”
Revision date: July 9, 2011
Last revised: by David A. Scott, M.D.