October 1, 2012
Individuals living with HIV may be more likely to have an urgent need for cardiac intervention than those without HIV, according to study results presented at ICAAC 2012. The results suggest, however, that inadequate screening may bear at least part of the blame.
In the study, researchers from Duke University and the University of North Carolina-Chapel Hill retrospectively evaluated data from 1996 to 2010 for patients from HIV specialty clinics within academic medical centers in the U.S. who presented for first-time catheterization. (First-time cardiac catheterization is considered the most probative diagnostic measure for coronary artery disease [CAD].)
Although data from several hundred HIV-infected individuals could have been included, only 96 HIV-infected patients were analyzed because the researchers wanted to focus on patients who were followed regularly.
The HIV-infected patient group was matched against a group of 41 randomly selected, HIV-uninfected people who also presented for first-time catheterization; efforts were made to match for age, sex and socioeconomic status -- though due to the demographics of the HIV-infected group, doing so proved challenging for the researchers.
Of the 96 patients with HIV, 54% were being treated for either a heart attack or chest pains that were suggestive of the imminent risk of a heart attack, as compared to only 34% of the 41 HIV-uninfected controls.
CAD was very common among the patients with HIV, 63% of whom had significant CAD, notwithstanding their young median age of 49 years. By comparison, 54% of the HIV-uninfected group (median age 50) had significant CAD. But because of the small study population, that difference was not statistically significant (P = .35).
"This suggests that many HIV doctors have not been doing long-term care and need to become more proficient at screening for cardiovascular disease," said lead author Charles Hicks, M.D., a professor at Duke University Medical Center.
A number of studies, including the D:A:D cohort and the NA-ACCORD study, have found that HIV-infected individuals tend to develop CAD more often and earlier than HIV-uninfected individuals, according to Hicks. More recently, a large U.S. study of more than 1.4 million individuals, approximately 6,000 of whom had HIV, found that the HIV-infected individuals were 43% more likely to die of a heart attack.
"Some of the things proposed as explanations include the inflammatory effect of immune system activation," Hicks said. "Perhaps people with HIV, especially if it is not treated and their immune system is turned on all the time, experience an inflammatory effect. We know that clots occur in greater frequency in the setting of inflammation, and people get a heart attack when a clot encounters a plaque-occluded coronary artery."
"A second possibility is that the medicines themselves or their side effects carry the risk; protease inhibitors have been linked to increased rates of CAD," Hicks added, noting that most, but not all, protease inhibitors are associated with increased lipid levels.
In the study, tobacco use was more common in those with HIV (51% vs. 36%, P = .14). End-stage renal disease was also more common among patients with HIV (15% vs. 0%, P = .01). Meanwhile, diabetes mellitus was more common in HIV-uninfected patients (42% vs. 23%, P = .04).
Hicks noted that the researchers had a difficult time finding matched control cases. "We usually like to have one control for every case, but in our study, we had only 41 controls, because we discovered that it was difficult to find controls of the same age as the cases, since CAD was occurring earlier in those with HIV," he said.
Research is ongoing; the researchers will next expand their analysis to include other subjects. "We're going to look at the difference in the management of traditional risk factors for CAD, the use of diagnostic cardiac imaging, and other patient populations," Hicks said, noting that as many as 5,000 to 6,000 HIV-infected patients could make up the size of the cohort.
The researchers hope to present new findings at CROI 2012 in Atlanta, next March.