Women experience a larger increase in CD4 cell count after starting HAART than men, according to a US study published in the August 2003 edition of Clinical Infectious Diseases. However, race is not a factor in CD4 cell change after HAART initiation with white, African-American and Hispanic individuals experiencing comparable increases in CD4 cell count.
In the US, the mortality rate amongst HIV-infected women is 20% higher than that seen in men. Significant differences are also evident between ethnic groups, with Hispanic HIV-positive individuals 20% more likely to die of HIV than white people, and African-Americans 50% more likely.
Investigators at the Thomas Street Clinic in Houston Texas, which offers HIV care to people who have no insurance, conducted an observational study involving 100 patients who experienced viral suppression in the first six months after starting HAART, to see if the higher mortality rate seen in women and Hispanics and African-Americans could be explained by differing responses to HAART.
At entry to the study, the mean CD4 cell count was 106 cells/mm3 and average viral load was 158,500 copies/mL. Of the 100 patients included in the study 23 were women, 50 were African-American, 31 Hispanic and 19 were white. Men and women did not differ significantly with regard to baseline CD4 cell count, baseline viral load, numbers coinfection with hepatitis C virus, age, injecting drug use, or stage of HIV disease. There were no differences between the racial groups in respect of baseline CD4 cell count, baseline viral load, numbers coinfection with hepatitis C virus, and the proportion of injecting drug users. However, none of the women in the study were white.
The majority of patients, 61, started a HAART regimen including a protease inhibitor, with 39 using a regimen including either an NNRTI or abacavir in combination with two NRTIs.
Six months after starting HAART, the mean CD4 cell count was 135 cells/mm3. However, the average CD4 cell count experienced by women was greater in women, 180 cells/mm3 than in men, 120 cells/mm3. This difference was statistically significant (p=.02).
The mean increase in CD4 cell count for white patients was 128 cells/mm3, 136 cells/mm3 for African-American patients, and 139 cells/mm3 for Hispanic individuals. These differences were not statistically significant (p=.93).
In multivariate analysis which included variables including age, past AIDS-defining illnesses, and baseline viral load, there was still no significant difference in CD4 cell response based on ethnicity, however patients who were treated with a protease inhibitor experienced a gain of 58 CD4 cells/mm3 than those receiving non-PI regimens (p=.03).
The results were further analysed controlling for baseline CD4 cell count, however, once again no significant differences were seen in CD4 cell response between ethnic groups.
As there were no white women in the study, the investigators excluded white men from further multivariate analysis to see if the sex differences persisted. Women continued to have a greater CD4 cell increase then men (p=.01).
The investigators comment, “after six months of receiving HAART, women had a greater CD4 cell response than men did, even after adjusting for baseline CD4 cell count and viral load.” In addition, “race/ethnicity had no effect on CD4 cell count in this study.”
The higher mortality rate seen in HIV-positive women, Hispanics and African-Americans could, the investigators suggest, be due to inequalities in access to healthcare rather than different responses to HAART. They highlight a recent study from Denmark, “where patients have free access to healthcare” which found that “nonwhite patients did not have decreased odds of receiving HAART or achieving viral suppression and had similar CD4 cell increases. Our results are consistent with these observations and suggest that disparities in outcome in the United States are not due to differences in CD4 cell response to viral suppression.”
Further information on this website
Giordano TP et al. Do sex and race/ethnicity influence CD4 cell response in patients who achieve virologic suppression during antiretroviral therapy?. Clinical Infectious Diseases 37 (on-line edition), 2003.