Infection with HIV, the virus that causes AIDS, can increase the risk of heart failure even in patients who don't have a prior history of heart disease, a U.S. study said.

And as the HIV virus replicates, the risk increases, added the study, published in Archives of Internal Medicine.

"Health care providers traditionally think of HIV and its therapies increasing the risk of atherosclerotic heart disease," said lead author Adreel Butt, at the University of Pittsburgh School of Medicine in Pennsylvania.

"The surprising finding from our study was the association of HIV with heart failure in the absence of prior coronary heart disease."

The study involved nearly 8,500 adults, with a median age of 48 years in both HIV infected subjects and controls.

The HIV group was more likely to also be infected with Hepatitis C, 31 percent to 11 percent, and to abuse cocaine -- 22 percent to 16 percent.

They were also more likely to be smokers but less likely to have hypertension or diabetes.

During a median follow-up of 7.3 years, 286 people developed heart failure. Rates of heart failure per 1,000 person-years, adjusted for age as well as race and ethnicity, were 7.12 for HIV patients and 4.82 for the controls.

After accounting for traditional risk factors, the hazard ratio for heart failure with HIV was 1.81.

In addition, ongoing replication of the virus led to a significantly higher risk of heart failure.

"On the other hand, if HIV replication is well controlled, then the risk of heart failure is closer to that seen among HIV-uninfected persons," Butt said.

The exact mechanism by which HIV infection is linked to heart failure remains unclear, but possible explanations include the direct effects of the HIV infection, antiretroviral treatment that leads to an increased risk of coronary heart disease, and nutritional deficiencies.

"Our results suggest that HIV itself is playing an important and independent role," Butt and her colleagues wrote.

The message for HIV care providers is clear, though.

"Be on the lookout for early signs of heart failure in HIV-infected persons, even if there is no history of preceding coronary heart disease," Butt told Reuters Health.

"Controlling HIV well may reduce the risk of heart failure."