For patients who stopped using these drugs, their risk for heart attack decreased within six months, Lundgren's group found.
"For those patients who have an increased underlying cardiovascular risk, then our suggestion is that these patients should consider whether there are other safer alternatives to these drugs," Lundgren said. "If there are safer alternatives, then patients should consider switching to those."
In a letter published in the same journal issue, GlaxoSmithKline, the maker of abacavir, said that their own analysis of 54 studies found no increase in the risk of heart attack from the drug.
GlaxoSmithKline spokesman Dr. Didier Lapierre wrote, "We did not find a result consistent with that of D:A:D... GSK takes the D:A:D finding seriously and is committed to understanding these data more fully and to communicating openly with treating physicians and regulatory agencies globally."
Didanosine is manufactured by Bristol-Myers Squibb.
Based on the data from D:A:D, the FDA said last week that it was conducting a safety review of both drugs.
"FDA continues to evaluate the overall risks and benefits of abacavir and didanosine. This evaluation may result in the need to revise labeling for the products. Until this evaluation is complete, health-care providers should evaluate the potential risks and benefits of each HIV-1 antiretroviral drug their patients are taking, including abacavir and didanosine," the agency said in a statement.
One expert thinks it's more important for patients to have their HIV under control; then they can worry about potential cardiovascular side effects.
"This is a surprising and provocative finding," said Dr. James Sosman, an associate professor of medicine at the University of Wisconsin School of Medicine. "We have not seen cardiovascular problems associated with abacavir."
Sosman noted that the use of antiretroviral drugs has replaced concerns about serious opportunistic infections in HIV patients with concerns about less serious risks like cardiovascular disease and diabetes.
"The most important thing for HIV patient is to control their HIV," Sosman said. "If they have excellent control with abacavir or didanosine, then you look for options to limit other risk factors. Patients not on HIV therapy have a higher risk of developing heart disease than people on HIV therapy," he said.
More information
For more on HIV, visit the U.S. National Institute of Allergy and Infectious Diseases.
