December 6, 2010
Over the past few years, the HIV clinical realm has seen an increased focus on the constellation of events that are associated with cardiovascular disease. In many ways, our understanding of cardiovascular risk in HIV-infected patients is still in its infancy. There remains a fair amount of uncertainty not only regarding the HIV- or antiretroviral-specific factors that increase this risk, but also regarding the strategies to employ in an effort to prevent, assess or manage the dangers of cardiovascular disease in people with HIV. But there is a lot we do know, and that knowledge can help guide clinicians as they determine the best way forward.
To discuss these issues, we brought together two of the leading minds on cardiovascular disease and HIV for a frank conversation: Marshall Glesby, M.D., Ph.D., the associate chief of the Division of Infectious Diseases and the director of the Cornell HIV Clinical Trials Unit at Weill Cornell Medical College; and Jens Lundgren, M.D., the chief physician and director of the Copenhagen HIV Programme. Both are at the forefront of research efforts in this area.
Myles Helfand: Let's start with an overview of the problem. Dr. Lundgren, if you could start us off; where are we right now in terms of how prevalent cardiovascular complications are among HIV-infected patients?
Jens Lundgren: This is an area that has been very much focused on during the last 10 to 12 years. As a consequence of that, a substantial amount of data have accumulated, which show that the risk of contracting cardiovascular disease for a person with a given age is slightly higher if this person is HIV infected, as opposed to not HIV infected.
The reasons for why there is such an excess risk are heavily discussed, and I think we will have a chance to discuss the details of that as we progress into this. But the theoretical possibilities are that: HIV-positive populations have an increased prevalence of traditional cardiovascular risk factors that drives an increase. For example, we know that the smoking prevalence in HIV-infected persons is higher than in the background population. That's one explanation.
The second potential explanation is that antiviral drugs are affecting the risk. We'll discuss that. The third sort of principle, or theoretical reason, is that the HIV itself is driving that.
There's a lot of research still to do to further understand this. But I think the safe thing to say here is that whatever problem that we have now in 2010 will be exacerbated in the next 10 years, given the fact that probably the strongest risk factor for cardiovascular disease and HIV is age. Obviously, as antiviral therapies keep people alive, they are aging into an age range where we know -- from the data on HIV patients, but also in the general population, of course -- that the risk of cardiovascular disease will increase. So we need, as HIV physicians, to be aware of this and be at increased vigilance around efforts to prevent cardiovascular disease. Because this will be something that, whatever the level of the problems that we have at the moment, will increase because of the aging of the population.
Myles Helfand: Is there research right now to suggest that we're already in the middle of a rising trend of cardiovascular disease among people with HIV?
Jens Lundgren: It's interesting. There are various studies that have been focusing on this. But it seems, at least in the studies that I'm aware of, that we are at a pretty stable level at the moment. I think that's likely because of the fact that there has been such attention on this in the last 10 years and therefore the various preventive efforts are now having an impact, both in terms of dealing with traditional cardiovascular risk factors, as well as antiviral drugs.
So, at the moment, we are not really at an increasing slope, other than the fact that, as more and more people are getting older, one would expect to see more events. Over and above that, at least from the data I've seen, we don't have an emerging big problem. But obviously, we need to be vigilant, too, to maintain this.
Marshall Glesby: If I could add just one thing to that: Clearly, there has been a lot of focus on coronary heart disease in the last 10 to 12 years, as Jens said. But I think there have been some other interesting trends that have emerged in recent years, as well. Particularly, several studies using echocardiography have been presented or published in recent years that suggest that dilated cardiomyopathy -- left ventricular dysfunction, which we used to see fairly commonly in the pre-combination antiretroviral era -- seems to have largely disappeared. But replacing it seems to be a higher prevalence of diastolic dysfunction. In some studies, up to 50% of people with HIV who undergo echoes will have some evidence of diastolic dysfunction -- often mild, and not clear if it's transient, or whether it will persist. I think the available data, although the controls have not necessarily been optimal in all of these studies, suggest that it is more common in people with HIV than in similarly aged controls from the general population.
I think the other interesting observation has been, in recent years, an increasing recognition of what appears to be a primary pulmonary hypertension in people with HIV. It's still fairly uncommon, but seems to be more common than in the general population, as well.
Jens Lundgren: I agree. That's an important observation. Just to supplement, and give the whole spectrum of this: We are studying strokes, as well, as a manifestation. Obviously, the risk factor profiles for strokes are different for coronary heart disease, hypertension being the lead responsible risk factor. But the number of strokes is now not necessarily trivial, pointing to the [need to be] very careful in your assessment of hypertension in your patients.
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