AIDS Drug Cocktails Also Increase Heart Attack Risk, Researchers Say

Treatment of HIV-infected people with cocktails of anti-AIDS drugs has strongly increased survival, but a major new study shows that it also increases the risk of heart attacks, researchers said here Thursday.

Clinicians have suspected as much for several years, but the study of nearly 24,000 patients provides the first strong evidence linking the treatment to myocardial infarctions.

Every year patients take the drug cocktails increases their risk of heart attacks by 26%, Dr. Jens Lundgren of the Hvidovre University Hospital in Copenhagen told the 10th Conference on Retroviruses and Opportunistic Infections.

The increase in risk is substantial, he said, but the absolute risk remains small. “These are relatively rare events,” he said. After six years of therapy there was an average of 6.4 myocardial infarctions per 1,000 years of patient treatment.

Nonetheless, Lundgren added: “Patients should be monitored very carefully and encouraged to make lifestyle changes to lower their risk.”

The increased incidence of heart attacks joins a growing list of side effects associated with HIV treatment, including abnormalities in fat distribution, an increased propensity toward diabetes and abnormalities in cholesterol metabolism. Many of those adverse effects have been associated with protease inhibitors -- the family of drugs that have had the greatest effect on fighting HIV infections.

“But we have to remind ourselves that [antiviral therapy] has produced dramatic improvements in survival,” Lundgren said.

“We can’t abandon it” because of side effects, added Dr. Judith Currier of UCLA. “As people are living longer, we need to pay attention to the things that impact mortality.”

Currier and Dr. Priscilla Hsue of UC San Francisco are independently conducting studies to explore how this effect might occur. For the moment they have obtained contradictory results.

Both are using ultrasound to assess the thickness of the walls of the carotid artery, the vessel in the neck that supplies blood to the brain. Previous studies in the general population have shown that increases in the thickness of the artery wall are associated with an increased risk of myocardial infarctions.

Currier has so far studied 44 HIV-positive individuals undergoing therapy with protease inhibitors, comparing each to two closely matched controls -- a patient who is HIV-positive but not taking protease inhibitors and one healthy individual. She reported Thursday that the group had not yet detected any increase in artery thickness.

Hsue has studied 106 HIV-positive patients who had been taking protease inhibitors for an average of four years. She reported, in contrast to Currier’s findings, that the thickness of their carotid arteries was “higher than expected from a large population study of similarly aged individuals.”

In a subset of 21 patients, her group monitored thickness over a period of a year and found that the increase during the period was about 10 times the amount that would be expected in healthy individuals.

Both groups are at a loss to explain the difference in findings between the two studies. But a key point is that Currier’s team excluded all HIV-positive individuals who had a family history of heart problems and those who had diabetes or high blood pressure, both of which are risk factors for heart disease. Hsue’s study included such individuals.