Social and economic circumstances impact on HIV treatment outcomes in US, Canada, Brazil, Australia

Women do worse everywhere, non-whites in US south do worst of all

Social and economic circumstances have an impact on the outcomes of HIV-positive patients, a multi-national study published in the February 15^th edition of the Journal of Infectious Diseases (now online) suggests.

Investigators monitored patients whose HIV was diagnosed soon after their infection occurred. During eight years of follow-up, women had poorer outcomes than men, and non-white patients living in southern US states were the group most likely to experience HIV-related illnesses.

The authors of an editorial acknowledge that socioeconomic factors “represent complex challenges that are beyond the traditional influence of public health.” However, they stress that failure to address social and economic disadvantages will undermine strategies for the management of the epidemic.

An international team of investigators from the Acute Infection and Early Disease Research Program (AIEDRP) wanted to know if sex and race had an impact on outcomes for patients recently infected with HIV.

They therefore designed an observational study including 2277 patients diagnosed with acute or primary HIV infection between 1997 and 2007 in Australia, Brazil, Canada and the US. Information was gathered on the patients’ clinical and demographic characteristics at the time of their diagnosis. They were then followed for up to eight years, and changes in their CD4 cell count and viral load were monitored, and data were gathered on the proportion of patients who started antiretroviral therapy and developed HIV-related illnesses.

Women constituted just 5% of the study sample. The majority of men (77%) were white, but most of the women (55%) were non-white.

On entry to the study mean viral load was 0.40 log₁₀ copies/ml lower in women than men (p = 0.001). There was also a significant difference in baseline CD4 cell count, which was a mean of 66 cells/mm³ higher in women than men (p = 0.001).

Possibly because of their lower viral load, women were 52% less likely than men to have two or more symptoms associated with primary HIV infection (p = 0.008). The investigators believe that this could lead to “less frequent diagnoses of primary HIV infection in women than men.”

Similar proportions of men and women (64% vs. 69%) started HIV therapy, and their CD4 cell counts were comparable at the time treatment was initiated (514 vs. 476 cells/mm³).

But non-white patients of both sexes were less likely to start therapy than white men and women. In addition, analysis showed that patients in the southern states of the US were the group least likely to start taking anti-HIV drugs (p = 0.047).

After six months of treatment, there was no difference in the proportion of men and women who had a viral load below 400 copies/ml. Increases in CD4 cell count were also comparable.

However, the investigators then analysed changes in the viral load and CD4 cell count of patients who remained off HIV therapy for up to three years.

By week 104, women had higher viral loads than men (difference, 0.24 log₁₀ copies/ml, p < 0.01) and after 24 weeks the CD4 advantage present in women at baseline had disappeared.

Mortality was equally low in men and women (approximately 1%).

However, non-white women (40%) were more likely to experience a drop in their CD4 cell count to below 200 cells/mm³ than non-white men (20%), white men (15%) and white women (5%, < 0.001).

During eight years of follow-up, 64% of non-white women had experienced an HIV-related illness compared to only 21% of patients in other groups. Moreover, AIDS-defining illnesses were diagnosed in 22% of non-white women compared to 6% of those in other groups.

“Despite the fact women had higher CD4 cell counts and lower viral loads at study entry, they subsequently experienced significantly more combined HIV-related and AIDS-defining events,” emphasise the investigators.

They do not believe that there are any grounds to believe that the sex differences in HIV-related illness have a biological cause, but “are the result of socioeconomic conditions.” These include “access to health care, health behaviors, lifestyle and environmental exposures.”

Regional differences were also apparent in outcomes. Eight years after diagnosis, 78% of non-white patients in the southern US had been diagnosed either an HIV-related illness or AIDS compared to 37% of whites in this region (p < 0.001), 24% of white patients in other areas (p < 0.001), and 17% of non-whites in other regions (p < 0.001).

“Strategies aimed at improving clinical outcomes among HIV-infected individuals in the southern United States, particularly nonwhites, are urgently needed to reduce HIV-related morbidity and mortality in North American women and men.”

This conclusion is echoed by the authors of the accompanying editorial. They note that the recently-released US HIV strategy has three goals: reducing the number of patients who are undiagnosed; increasing access to care and improving health outcomes in patients with HIV; and reducing HIV-related health disparities.

But they believe “the findings from this study threaten the success of each of these pillars.” They therefore call for “a collaborative policy and research effort across all levels of community, government and science.”