Some HIV Drugs May Up Heart Risk
Study Suggests Increased Heart Attack Risk With Increased Use of Protease Inhibitors
April 25, 2007 -- Long-term use of a class of HIV drugs called protease inhibitors may raise heart attack risk, researchers report.
However, the possible risk appears to be "low or at most moderate," states an editorial published with the study in The New England Journal of Medicine.
The study comes from researchers including Nina Friis-Moller, MD, PhD, of Denmark's University of Copenhagen.
They analyzed data on more than 23,000 patients with HIV, the virus that causes AIDS.
The patients were treated at 188 clinics in Europe, the U.S., and Australia. They were 39 years old, on average, when the study started. Women accounted for nearly a quarter of the group.
The patients were followed for up to six years, from 1999 to 2005.
A total of 345 patients had a fatal or nonfatal heart attack during the study. Heart attacks were associated with an increasing length of exposure to antiretroviral drugs, which target HIV.
The researchers took a closer look at the data. They adjusted for various factors including drug combinations used to treat HIV.
In those analyses, protease inhibitors were associated with a 16% increase in heart attack risk. That risk may be due to a rise in levels of blood fats such as triglycerides, the researchers note. When they took that into account, there was still an increased risk of 10% for protease inhibitors.
Examples of some protease inhibitors are Crixivan, Norvir, Viracept, Agenerase, and Kaletra.
Other HIV drugs called nonnucleoside reverse-transcriptase inhibitors weren't associated with increased heart attack risk. Examples of this type of drug include Viramune, Sustiva, and Rescriptor.
The study doesn't prove that protease inhibitors cause heart attacks.
The researchers didn't directly test protease inhibitors. Instead, they looked for patterns in the patients' heart attacks and antiretroviral drug use.
The scientists also note that their analysis likely missed "factors that are unknown or are not routinely or easily identified or measured."
Heart Attack Risk Considered Low
Editorialist James H. Stein, MD, writes that the incidence of heart attacks among patients who took protease inhibitors for more than six years "was only 0.6% per year."
"This level of cardiovascular risk would be considered low or at most moderate, depending on a patient's risk-factor burden," writes Stein, who works at the University of Wisconsin School of Medicine and Public Health.
"Thus, there does not appear to be an epidemic on the horizon -- simply a risk that needs to be managed," Stein continues.
Aggressive HIV treatment is "clearly the main clinical priority," Stein writes. He calls for lengthier studies on antiretroviral drugs and heart attack risk.
"Patients with HIV infection are living longer -- that's the good news," writes Stein. "But the longer you live, the more likely it is that heart disease will develop, so the treatment of modifiable risk factors is prudent."