People with HIV should be screened regularly for kidney disease because even slight kidney damage can lead to an increased risk of heart problems, according to a presentation at the 2010 International AIDS Conference in Vienna, Austria.

Dr. Mohamed Atta, an Associate Professor of Medicine in nephrology at the Johns Hopkins School of Medicine and medical director of the Dialysis Center at DaVita Health Care in Baltimore, spoke about kidney complications and deferred versus early HIV treatment at a session on side effects of antiretroviral therapy.

Kidney disease is a common problem in HIV-positive adults, with chronic kidney disease affecting an estimated 15 percent to 20 percent of people with HIV. Kidney damage can be caused either by HIV itself if left untreated, which is called HIV-associated nephropathy (HIVAN), or by antiretrovirals used to treat HIV.

Both types of kidney damage are worrisome because studies have shown that even slight kidney malfunction is a significant predictor of heart complications and death due to heart disease.

“When investigators actually started looking at the best predictor of cardiovascular outcome, it was microalbuminuria,” said Dr. Atta. Microalbuminuria is the presence of a small amount of a protein, called albumin, in the urine and is an early sign of kidney damage.

Protein in the urine is often a sign of kidney malfunction. Studies have found that even the smallest indication of protein in the urine is associated with increased heart failure and mortality, regardless of HIV status.

Treatment and prevention of kidney disease depends on its cause. HIV-associated nephropathy is usually a sign that HIV has progressed to the point that antiretroviral treatment is needed. It rarely shows up in people who do not have advanced HIV infections.

“We showed…that patients [with HIVAN] who were treated with antiretroviral therapy have better [kidney] survival versus those who were not treated with HAART [highly active antiretroviral therapy]. This is why now the guidelines recommend that HIVAN is an indication to start HAART,” said Dr. Atta.

However, there is some evidence that antiretroviral therapy itself can also lead to kidney damage. Crixivan (indinavir) has been associated with formation of kidney stones. Viread (tenofovir) has also been linked to kidney damage, although the reason for the damage is not yet clear.

Dr. Atta also discussed a recent European study that found an association between chronic kidney disease and use of Viread, Crixivan, Reyataz (atazanavir), or Kaletra (lopinavir/ritonavir).

The potential for antiretrovirals to cause kidney damage leads to the question of whether treatment should be delayed to help spare the kidneys.

“In my mind, as a nephrocentric [kidney-focused] person, the deferred treatment carries the risk of heightened HIV-associated nephropathy; the early treatment is associated with heart toxicity and metabolic derangement,” said Dr. Atta.

In the end, he said, “There is no evidence of benefit from the [kidney] standpoint of early HIV treatment” unless it is necessary to treat HIVAN. However, he said, HIVAN is usually “a late manifestation of HIV.”

Dr. Atta concluded by stating that physicians should screen all HIV patients for kidney function, whether taking antiretrovirals or not, and that high-risk patients should be monitored for kidney disease on a regular basis.

For more information, please see the AIDS 2010 webpage on the Kaiser Family Foundation website.