Doesn't HIV Treatment Increase the Risk of a Heart Attack?
A number of studies have investigated the impact that antiretrovirals (ARVs) may have on heart disease risk. While it is true that many HIV drugs can cause side effects that may increase the risk of heart attacks or strokes, studies have also demonstrated that ARV therapy as a whole may actually protect against cardiovascular disease.
One study that clearly defined the value of ARV therapy in terms of preventing heart disease in people with HIV was the large, international Strategies for Management of Antiretroviral Therapy (SMART) trial. SMART enrolled people with CD4 counts above 350, who were either on treatment or had not yet started therapy. They were randomized to one of two groups: a continuous treatment group that did not stop HIV treatment, or a deferred group that either delayed or stopped treatment until the CD4 count fell below 250, restarted until the CD4 count rose above 350, then stopped again until it fell below 250, and so on.
The trial was initiated, in part, because of the belief that ARV drugs could contribute to heart disease risk. Researchers reckoned that the less time people spent on ARV drugs, the fewer heart problems they would have. Contrary to expectations, however, there were more heart attacks among those who delayed or stopped treatment, compared to those who started and remained on therapy.
Confusing matters is the fact many antiretrovirals have been linked to side effects that can potentially increase the risk of cardiovascular disease. Many protease inhibitors (PIs), some non-nucleoside reverse transcriptase inhibitors (NNRTIs) and a few nucleoside reverse transcriptase inhibitors (NRTIs) have been found to cause lipid abnormalities in people with HIV. PIs and NRTIs have also been tied to diabetes—another cardiovascular disease risk. Some drugs have also been linked to an increased risk of heart attacks, for reasons that are not yet clear.
While experts agree that cardiovascular risks are associated with HIV treatment, there are established cardiovascular—as well as immunological—benefits as well. And just as there needs to be a favorable balance between the cardiovascular risks and benefits of ARV therapy, there are ways to maintain a favorable balance in people using these medications. This involves working closely with a health care provider to make sure that all cardiovascular risks—including smoking, diet, exercise, family history, blood pressure and current lipid levels—are considered when making treatment decisions. Monitoring these risk factors during HIV treatment is essential as well.
Following is a guide to the various drug classes and their impact on cardiovascular disease:
Zerit (stavudine) can increase lipids, among other side effects, and most health care providers recommend avoiding it when possible.
•
Zidovudine (found in Retrovir, Combivir and Trizivir) can increase the risk of developing diabetes—a risk factor for cardiovascular disease—and, in rarer cases, can damage heart muscle.
•
Abacavir (found in Ziagen, Epzicom and Trizivir) and didanosine (found in Videx and Videx EC) have been found to increase the risk of heart attacks. These results still need to be confirmed, and experts are still working to determine the mechanism by which these drugs increase that risk.
Efavirenz (found in Sustiva and Atripla) can modestly increase triglycerides as well as raise healthy HDL. Viramune (nevirapine) has no impact on cholesterol or triglycerides, except for HDL increases.
•
Rescriptor (delavirdine), rarely used because of three-times-daily dosing, can modestly increase cholesterol and triglycerides.
•
Intelence (etravirine), the newest NNRTI, appears to have a little effect on cholesterol or triglycerides.
Most of the PIs can raise total and LDL cholesterol and triglycerides, and using Norvir (ritonavir) to boost blood levels of the PIs can exacerbate this effect.
•
Reyataz (atazanavir) does not appear to raise lipid levels. However, when it is combined with Norvir, lipid levels may be affected.
Search for news stories about this topic
