CVD Risk Highlighted in HIV-Positive People

By Michael Smith
BOSTON, 20 june 2008 -- Now that antiretroviral therapy has turned HIV into a chronic disease, doctors need to start paying more attention to the cardiovascular health of their patients.
That's the conclusion of a "State of the Science" meeting that "crystallized what we know and what we don't know" about HIV and cardiovascular disease," said Steven Grinspoon, M.D., of Massachusetts General Hospital, who was co-chair of the meeting.
One key piece of knowledge is that people living with HIV have an increased risk of cardiovascular disease, Dr. Grinspoon said, but what is not known is how much of that can be blamed on HIV and how much on the medications used to treat the virus.
Although there are gaps in the science, Dr. Grinspoon said, doctors should not wait until they are filled in. "We need to aggressively determine who is at risk for cardiovascular disease and treat them," he said.
Dr. Grinspoon added that standard tools for determining cardiovascular risk -- such as the Framingham Risk Score -- "successfully identify people (with HIV) at risk for cardiovascular disease" even though they are not specifically designed for the task.
The results of the conference, held last June, are summarized in seven papers published online today in Circulation and the Journal of Acquired Immune Deficiency Syndromes.
The papers cover the epidemiology of HIV and cardiovascular disease, methods of screening, the effects of HIV on vasculature, and the role of metabolic abnormalities, among other issues.
Several studies have shown a relatively high incidence of cardiovascular disease among those living with HIV, reported Judith Currier, M.D., of the University of California Los Angeles Care Center, and colleagues.
Indeed, one study showed a rate of myocardial infarction of 11.18 per 1,000 person-years in an HIV-positive cohort, compared with 6.98 among people without HIV, the investigators reported.
The absolute rate is usually lower, but still 1.5- to two-fold higher than that seen among HIV-negative populations, they said.
The landmark DAD study (Data Collection on Adverse Events of Anti-HIV
Drugs) found an absolute rate of first MI of 3.7 per 1,000 person years, but also found the risk increased by 16% for every year of treatment with antiretroviral drugs, they noted.
When the DAD researchers adjusted for dyslipidemia, Dr. Grinspoon said, the risk was reduced by about half, suggesting that traditional risk factors such as low HDL cholesterol and elevated triglycerides, also play a role.
Another recent large trial -- the SMART study -- compared interrupted and continuous anti-HIV therapy to test the idea that stopping treatment might increase HIV replication but would result in a lower risk of cardiovascular adverse events.
Instead, the interruption arm saw an increase in deaths, progression of HIV, and other major adverse events, including cardiovascular disease.
The implication, Dr. Grinspoon said, is that letting HIV progress leads to damage to the heart and vasculature, possibly through an HIV-sparked inflammatory process.
"We have learned a lot about cardiovascular disease and HIV," Dr. Grinspoon said. Among the known facts:
The risk of cardiovascular disease is elevated in people with HIV.
The elevations in risk are at least partly associated with anti-HIV medications, but the effects are agent-specific, rather than class-specific, as had been thought.
Existing screening algorithms, although not designed to take HIV into account, do identify the traditional risk factors that play a role in the elevated risk.
The rate of cigarette smoking remains higher among people with HIV than in the population at large.
Dr. Grinspoon added that "we're pretty sure" continuous antiretroviral therapy reduces cardiovascular risk, based on the SMART study, although more research is needed on the question.
He said gaps in knowledge include:
The relative contribution of traditional risk factors and non-traditional factors, such as inflammation.
How HIV and inflammation affect the vasculature.
A lack of large randomized trials among HIV-positive people testing methods of reducing cardiovascular disease. Instead, he said, doctors have to "rely on strategies tested in non-HIV people."
There are no HIV-specific algorithms to screen for risk.
And it's not known how HIV medications interact with such things as lipid-lowering or anti-smoking drugs.
Finally, Dr. Grinspoon said, researchers still don't understand why people with HIV smoke so much.
"Doctors should be aware of a unique set of risks for cardiovascular disease in HIV people," he said. But while they wait for those factors to be clarified, they should use their knowledge of traditional cardiovascular risk factors to screen and treat people with HIV.
"We need to identify those at risk and then treat aggressively," he said.
The conference was sponsored by the American Heart Association, American Academy of HIV Medicine, and Bristol-Myers Squibb. Many of the authors reported financial links with corporate entities. In particular, Dr. Grinspoon reported links with Bristol-Myers Squibb, heratechnologies, and Serono Labs.
Primary source: CirculationSource reference:Grinspoon SK, et al "State of the Science Conference: Initiative to decrease cardiovascular risk and increase quality of care for patients living with HIV/AIDS" Circulation 2008; 118: DOI: 10.1161/circulationaha.107.189622. Additional source: CirculationSource reference: Currier JS, et al "Epidemiological evidence for cardiovascular disease in HIV-infected patients and relationship to highly active antiretroviral therapy" Circulation 2008; 118: DOI: 10.1161/circulationaha.107.189624. Additional source: CirculationSource reference: Dubé MP, et al "Effects of HIV infection and antiretroviral therapy on the heart and vasculature" Circulation 2008; 118: DOI: 10.1161/circulationaha.107.189625.