The widespread use of highly active antiretroviral therapy (HAART) with nucleoside reverse transcriptase inhibitors (NRTIs) has transformed HIV/AIDS from an automatic death sentence to a chronic, frequently controllable condition. But according to a 2008 FDA analysis, Data Collection on Adverse Events of Anti-HIV Drugs (DAD), an NRTI called abacavir (Ziagen) increases the risk of heart attack by 90%. Another such drug, didanosine (Videx), elevates that risk by 49%.
The analysis examined 3 other NRTIs -- zidovudine, stavudine and lamivudine -- none of which appeared to increase the chances of heart attack. Researchers did not look at 2 other NRTIs: tenofovir and emtricitabine.
Drugs Still Used
Even though this increased risk seems alarming, researchers are quick to point out that they had not established a cause-and-effect relationship between the drugs and heart attack. The cardiovascular hazards associated with abacavir and didanosine did not increase with longer use and disappeared 6 months after patients stopped taking them.
No warnings to not prescribe these medications have been issued, nor have further regulations been recommended. But physicians have been advised to report any negative reactions to abacavir and didanosine.
Other Cardiovascular Risk Factors
The increased threat of some NRTIs seems to be made worse when patients also have other risk factors for heart disease:
- Personal history of heart disease
- High cholesterol
- High blood pressure
- Diabetes
- Smoking
- Advanced age
The HAART-Heart Connection
It may be that the NRTIs used in HAART therapy make cardiovascular events more common in people with HIV because they lead to lipodystrophy, which is a redistribution of body fat on the patient's body. Lipodystrophy can cause fat to accumulate in the back of the neck, the abdomen and, in some cases, women's breasts. At the same time, fat may be lost in the face, buttocks and limbs.
Insulin Resistance and Dyslipidemia
Some potentially dangerous changes in your metabolism can result:
- Insulin resistance: The body's insulin can become increasingly unable to carry glucose (blood sugar) from the bloodstream into the cells; this condition can lead to diabetes
- Dyslipidemia: The amount of lipids (cholesterol and triglycerides) in the blood can increase, which can lead to cardiovascular disease.
Patients can fight lipodystrophy by following a "Mediterranean diet" -- a diet lower than usual in fats (especially saturated fats), refined sugars and alcohol and high in whole grains, beans, fruits and vegetables. The increased fiber in the diet may reduce abdominal fat and control insulin resistance.
Aerobic exercise, which raises the pulse and sends more blood to the muscles, is also recommended. Medications such as growth hormones and metformin (Glucophage), a diabetes drug, are sometimes prescribed for those with lipodystrophy.
Sources:
"Early Communication About an Ongoing Safety Review of Ziagen (Abacavir)." fda.gov. 27 Mar. 2008. U.S. Food and Drug Administration. 29 Oct. 2008 <http://www.fda.gov/CDER/Drug/early_comm/abacavir.htm>.
D.A.D. Study Group. "Use of Nucleoside Reverse Transcriptase Inhibitors and Risk of Myocardial Infarction in HIV-Infected Patients Enrolled in the D.A.D Study: a Multi-Cohort Collaboration." The Lancet 371:9622(2008):60423-7. 29 Oct. 2008 <http://www.thelancet.com/journals/lancet/article/PIIS0140673608604237/abstract>.
"HIV/AIDS Update -- Early Communication About an Ongoing Safety Review of Ziagen (Abacavir) and Videx (Didanosine)." idsociety.org. 2007. Infectious Diseases Society of America. 29 Oct. 2008 <http://idsociety.org/Content.aspx?id=10864>.
Kressy, Jean, et al. "Lipodystrophy." tufts.edu. 24 Jun. 2008. Tufts University. 29. Oct. 2008 <http://www.tufts.edu/med/nutrition-infection/hiv/health_lipo.html>.
"Top Things to Know: Cardiovascular Disease in HIV-Infected Patients." americanheart.org. 19 Jun. 2008. American Heart Association. 29 Oct. 2008 <http://www.americanheart.org/downloadable/heart/1213717410917topTenHIV.pdf>.
