The Body Covers: The 45th Annual Meeting of the Infectious Diseases Society of America
IDSA 2007 Study Summaries: An Interview With Kristin Mondy, M.D.
October 6, 2007
Welcome. This is Bonnie Goldman, Editorial Director of The Body PRO. I'm in San Diego at IDSA 2007, one of the year's HIV conferences. Right now, I'm in the poster session where researchers are standing in front of their posters. There's nothing like hearing the results of research directly from those who actually conducted the research. It is these women and men who are transforming HIV treatment and care. In this podcast, the researchers will introduce themselves and then summarize their study. After their summary, I'll ask a few questions.
I'm Dr. Kristin Mondy, Assistant Professor at Washington University Medical School in St. Louis. The title of the poster1 is "Effects of HIV in Highly Active Antiretroviral Therapy, or HAART, in an Aging Outpatient Population." The background is that people are living much longer with HIV and based on other studies, recommendations are, once you start antiretroviral therapy, you should continue it and never stop.
On the other end of the spectrum, however, there are some concerning data that people on antiretroviral therapy definitely have a risk of some other metabolic complications. This may include metabolic toxicities such as premature heart disease, renal toxicity, increased risk of diabetes and bone metabolism complications.
These by and large have not been studied in older populations. Particularly in the setting of clinical trials, older patients are excluded a lot of times. Most studies that have looked at older HIV patients have really compared them to younger HIV patients. But that doesn't really get at the question of: What is HIV or therapy contributing to the normal aging process?
So the idea [of our study] was to look at our older aging population -- anybody over age 50 -- and to somehow compare them to people that were of the same age that were HIV negative. The easiest way that we could do that at the time was to compare it to a known database of the CDC [U.S. Centers for Disease Control and Prevention], just out of the National Health and Nutrition Examination Survey, or NHANES cohort. [Click here to find out more about this cohort.] So we went ahead and we matched them by age, race, gender, smoking and BMI [body mass index].
We have a pretty small cohort. That's the one drawback of the study. It's only 70 patients and we have combined with another site, but I don't have their data for this analysis. The hypothesis was that in a number of these metabolic parameters, the ones that are in the table -- renal, bone, risk of heart disease, risk of diabetes -- that there would be a significant difference and that people with HIV would be significantly worse.
What we found is that ... well, we really didn't find that. The mean age was 56 -- this was matched. We did find that by and large, the majority -- about 86% -- were men and I think that's reflective of the early epidemic; that early on, it affected mainly [men]. Also you can see that the majority were white. So it mainly affected gay, white men, early on.
The mean current CD4 count was actually quite high: 510. Out of this population, 90% were on therapy. Out of the persons on therapy, 91% were undetectable.
So there has been other data in aging people ... that this is reflective of older people. They are very adherent. They also tend to be adherent, not only to their HIV medicines, but other medicines, like antihypertensives, lipid-lowering therapy, whatnot. I think that might explain some of the findings.
We did see suspected differences, for instance, in some things like LDL [low-density lipoproteins] and triglycerides, that we know in the usual population. I can go over some of the differences. But when you really look at the absolute numbers, they are really not that bad. I think that's reflective of current therapies that people are on. We had a lot of people on newer protease inhibitors, like atazanavir [brand name: Reyataz; also known as: ATV], ritonavir [brand name: Norvir; also known as: RTV], nevirapine [brand name: Viramune; also known as: NVP] and efavirenz [brand name: Sustiva, Stocrin; also known as: EFV].
Things that we might have expected ... for instance, when we looked at history of MI [myocardial infarctions] at any time, it was very low in both groups. For the HIV infected it was just four persons, or 6%. Only seven persons over 50 had a known diagnosis of coronary artery disease. Equal or very similar numbers had diabetes: 13% in our group; 11% in the other group.
Hypertension was a significant difference. I can't really explain that. That might be the sample size. Other people have seen more hypertension in HIV than non-HIV [infected people] but attribute that to metabolic syndrome. I can tell you that between the two, since we matched on all these other parameters, there was no significant difference in rates of metabolic syndrome.
Another thing was, when we looked at bone mineral density -- in the NHANES [cohort] they don't look at lumbar, spine, bone mineral density -- and that, in HIV-infected people, tends to be a little bit lower. Overall, there was not a big, significant difference in bone mineral density and T scores, which was somewhat surprising from other data.
On the other hand, these people have been on HAART for a mean number of seven years. We have done some other studies, looking at longitudinal bone data over time, and it seems like, when you first start HAART, you have a dip, and then it seems to slowly maybe go up and stabilize. I think we are catching these people at a different snapshot time point. Maybe by this time they have stabilization on HAART, and because of age, the HIV-negative group has kind of caught up to the HIV-positive group, and they were similar.
Same thing with maybe risk of heart disease or diabetes. When you are looking purely at more people that are now older, and you're looking at an effect of age, it's more significant -- the effect of age is now more significant than HIV or HAART, and may explain why there is a similarity.
Do you know how long these people have been infected?
I think it was a mean of 10 years. And that was time since HIV diagnosis. It's hard to say; that's when they were diagnosed.
I see that they were mostly on PI [protease inhibitor] regimens?
Yes, they were. So a lot of the data on metabolic complications are on PIs. My response to that is that most of those studies on PIs, they started way back when we didn't have very metabolically friendly PIs. We don't have people on some of those earlier regimens so much anymore. I can thank some of my other colleagues who changed them to friendlier regimens! And the nukes, too. We changed nukes, too. We are not on d4T [generic name: stavudine; brand name: Zerit], AZT [generic name: zidovudine; brand name: Retrovir] ... I mean, we really are on non-thymidine analogs now.
But we don't see a big difference in renal function. We use a ton of tenofovir [brand name: Viread; also known as: TDF] in our clinic. But again, it may be that the effect of aging is now more important than the effect of a drug. We don't know data that people have been on tenofovir for such a really long time. Again, this is just what I have heard. Also with that drug, there seems to be a stabilization over time. But we need ...
[Background discussion with Judy Aberg, M.D.]
They have been on HAART a long time, so I don't think they started on tenofovir and that means other things. They wouldn't have been on it a really long time. We need more longitudinal data. We're working with the University of Pennsylvania to try and get more patients. They just haven't given us their data. So we're going to try and get more. I give the credit to my fellow, who individually has gone to every clinic and recruited these people.
Great. Thank you very much.
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