The Lingering Debate With Abacavir and Heart Disease

The debate continues on the possible increased risk for heart attacks when using Ziagen (abacavir), a result that was first released about 2 years ago. The D:A:D study, which follows the side effects of HIV drugs, earlier reported that the drugs in general increase a person's risk for heart attack by 26%. Further surprising data from the same study in 2008 found Ziagen itself increased this risk by 90%. Since Ziagen is still an option, frequently prescribed for those with kidney disease who may not be able to tolerate the often prescribed Viread (tenofovir), more research has been done to settle this finding.

Since then, more than a dozen other studies have also reported on heart disease in HIV with conflicting data. An updated analysis from D:A:D continues to show risk, as do results from a smaller Canadian study. The STEAL study of about 360 treatment-experienced people also found a higher rate of non-AIDS events due to cardiovascular factors.

On the other hand, the HEAT study of about 700 treatment-naive people found no increased risk when comparing abacavir + 3TC to tenofovir + FTC. A large VA study (19,000 people) supports the HEAT observation after adjusting for typical risk factors like heart disease, kidney disease and hepatitis C.

Similarly, the Spanish BICOMBO study of 80 people showed no increased risk for heart attack. The group who took abacavir did have a higher rate of cholesterol than the tenofovir group, but abacavir did not increase many other markers of heart attack risk, such as inflammation or insulin resistance -- the same markers used in the D:A:D. Further, a French study reported that the risk for heart attack was not significant, after adjusting their results for drug use.

In the meantime, as researchers tease out these results, what does this mean for people on therapy? If other cardiovascular risk factors are present at a moderate or high degree, such as smoking or diabetes or hypertension, one might choose not to use Ziagen (or Epzicom or Trizivir) to be on the safe side. For others, with few or no additional risk factors, taking Ziagen may be the right choice given its other proven benefits as an HIV drug. In any case, making decisions of whether to use Ziagen should be made in consultation with a health care professional who understands the latest data and can individualize therapy due to the many HIV drug options.