February 6, 2008
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There's nothing like hearing the results of studies directly from those who actually conducted the research. It is these women and men who are transforming HIV treatment and care. In this interview, you'll meet one of these impressive HIV researchers and read an explanation of the study she is presenting at CROI 2008.
My name is Diana Lemly, and I am currently at Vanderbilt University Medical Center. I am here presenting the poster "Race and Sex Differences in HAART [Highly Active Antiretroviral Therapy] Use and Mortality Among HIV-Infected Persons in Care."1 This is a study that was conducted in Nashville, Tenn., at the Comprehensive Care Center. We included all patients who were in care, defined as having at least one provider visit at the same clinic in Nashville between January 1998 and December 2005. We were looking specifically at differences in HAART use and differences in mortality over the course of the study.
Diana Lemly, M.D.
In terms of our results, the study included about 2,600 patients with a median follow-up of two years. Thirty-eight percent of the study population would be termed non-Hispanic blacks and 62% were non-blacks. We had 24% women and 76% men. We found that there was an overall mortality rate of 38 deaths per 1,000 person-years. When we looked specifically at the unadjusted, all-cause mortality rates, we found a significant difference: that blacks had a higher mortality rate, at 49 deaths per 1,000 person-years, compared to 31 deaths per 1,000 person-years among non-blacks. This was statistically significant. The unadjusted, all-cause mortality rates between women and men were more similar and were not statistically significant.
When we looked at some of the factors at enrollment we found that, comparing blacks to non-black patients, the baseline CD4 count was lower in black patients, at 304, compared to 336 in non-black patients. This was a significant difference. When we looked at presentation between men and women, we found that CD4 count was higher in women at presentation. This was 366 compared to 312 in men. Again, this was a significant difference.
The next component of the study was looking at [patients'] HAART use. The way we captured this was by [examining] the proportion of time in care on HAART; this was the number of days that they were on HAART divided by the number of days that they were in care. We found significant differences again: We found a median proportion of time in care on HAART for blacks was 47% compared to 76% for non-blacks. For women, this was 57% of the time they were on HAART compared to 71% of the time men were on HAART.
To make sure that this was a real difference and not just explained by differences in CD4 count, we looked at the same variable with regards to just those people who started out with a baseline CD4 count less than 200. This is a population [in which] we would expect the vast majority to be on HAART throughout their time in care. Again, [we] found differences: 70% of the time blacks were [in] care compared to 91% of the time for non-blacks, and 74% of the time for women compared to 88% of the time for men.
Finally, we created models to look at factors associated with death. In a model that examined baseline factors including race, sex, history of IV [intravenous] drug use, previous AIDS diagnosis, their age at entry, as well as their baseline CD4 count, we found an association between black race and death as well as female sex and death.
Then we repeated the same model, but [adjusted] for the time in care on HAART. With the second model, we found that there was no longer an association between black race and death, but there remained an association between female gender and death. This leaves us with [the conclusion] that there [are] still very significant race and sex disparities [regarding] both HAART utilization and survival. It seems like part of this is related, of course, to HAART utilization. But that really only seemed to explain the differences we saw with black race; [there are] certainly other factors that were not examined. Whether these may be related to social barriers to care or even response to HAART, that's not being included [in this analysis].
Can you characterize the population that this clinic serves? Is it a Ryan White [CARE Act]-funded clinic?
It is. It's a primarily urban clinic that is really the only major HIV clinic for all of the middle Tennessee area. There's still a fairly diverse draw in terms of both people living in Nashville [as well as those who come] from outside and more rural communities, but [who] still come into this clinic. It is predominantly an urban clinic.
Do you give vouchers for transportation at the clinic?
I don't know specifically about vouchers for transportation. One thing that is important -- and you're touching on access-to-care issues and insurance status, which is something we don't include in this analysis -- but during the time of the study up through 2005, TennCare, which is our version of Medicaid, provided coverage for all HIV-positive Tennesseans. So there wasn't a significant proportion who didn't have insurance. There would have been a difference between public and private insurance. Unfortunately, that has changed since we ended this study. One of the reasons we followed just until the end of 2005 was to try and capture a time where at least there was less of a barrier to care with regards to insurance. Now, unfortunately, they've changed a lot of the access to TennCare among the HIV-positive population, so it's become even more of an issue.
It's more difficult to access care, then?
Yes. Now, because the coverage has been reduced for many HIV-positive patients, there's been much more need for Ryan White funds [or] for other access to medications.
This could be more dire now?
Is there any idea why there is a greater death rate in women?
We don't have any answers at this point. I think, [after] talking with various people here, certainly some of the social factors that we've touched on may play a role. Any barrier to being able to continue care [could be a factor], whether it be continued drug use or alcohol use, mental illness, or just increased social responsibilities. Someone even suggested looking at the number of children in the home, and whether this could be associated with some type of barrier to [women] being able to take care of their own health. I think at this point we really don't know. One of the reasons that we were so surprised by this analysis was, "Why can we at least explain part of the association between black race and mortality with this difference in HAART use, but it doesn't seem to explain the difference in women or the association with gender?"
But it is interesting that the difference in HAART use is so striking.
Yes. It's not subtle. We're not talking a few [percentage] points.
Are these people who were once in care and are no longer in care?
The only definition for care was having had at least one visit, so we didn't exclude individuals who may have been treated at some point prior to entering care at the Comprehensive Care Clinic. We also didn't exclude individuals who had no prior care. It was looking [only] at their start at this particular clinic.
It's disheartening to see yet another study that shows both women and African Americans are at a greater risk for death because of lack of access to care.
Yes. Certainly, thinking of the populations where we see greater prevalence and incidence among African-American women, just to see that we're not doing a good enough job addressing these differences and creating an environment where everyone can have the best outcome -- it is disheartening.
This transcript has been lightly edited for clarity.
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