Black MSM are 60% less likely to have suppressed HIV than white men in Atlanta

Differences explained by age profile and inequalities in access to health care, income and housing

A lack of viral suppression was significantly more prevalent among black HIV-positive men who have sex with men (MSM) in the US city of Atlanta than among white MSM, with black men 60% less likely to have suppressed virus than white men. The racial disparity could be completely accounted for by differences in age, access to health care, income, housing stability and marijuana use, Dr Justin Knox from Columbia University told the Conference on Retroviruses and Opportunistic Infections (CROI 2020) last week.

National US statistics have indicated consistent racial disparities in terms of viral suppression, with HIV-positive black men estimated to be 30% less likely to achieve viral suppression than white MSM. However, most of these data are from clinical cohorts of men who are already in HIV care. There are few data from community-based studies sampling men who may potentially not be accessing HIV care at all or inconsistently.

The study

As part of the Engagement Study – a community-based prospective cohort study – clinical and behavioural data were collected from 398 HIV-positive black and white MSM living in Atlanta between 2016-2017.  In addition to sociodemographic data, viral suppression was recorded (defined as a viral load below 40 copies/ml) and data were gathered on possible explanatory factors.

Black MSM comprised 52% of the total sample; 55% of black men and 33% of white men were under the age of 40. Around half of the black men had an income under $20 000, compared to only 29% of white men. Thirty per cent of black men were in unstable housing or homeless compared to 17% of white men; similarly, black men were more likely to have been incarcerated in the past year (15 vs 7%) and not to have insurance or government programme coverage for antiretroviral therapy (ART, 14 vs 5%). Marijuana use was higher among black men (62 vs 37%) while methamphetamine use was higher among white men (23 vs 12%).

Results

Glossary

virological suppression

Halting of the function or replication of a virus. In HIV, optimal viral suppression is measured as the reduction of viral load (HIV RNA) to undetectable levels and is the goal of antiretroviral therapy.

community setting

In the language of healthcare, something that happens in a “community setting” or in “the community” occurs outside of a hospital.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

opportunistic infection (OI)

An infection that occurs more frequently or is more severe in people with weakened immune systems, such as people with low CD4 counts, than in people with healthy immune systems. Opportunistic infections common in people with advanced HIV disease include Pneumocystis jiroveci pneumonia; Kaposi sarcoma; cryptosporidiosis; histoplasmosis; other parasitic, viral, and fungal infections; and some types of cancer. 

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 

Of the total sample, 33% of black men were found not to have suppressed virus, compared to 19% of white men. This led to a prevalence ratio of 1.6 (confidence interval 1.1-2.5) indicating that black men had a 60% higher prevalence of lack of viral suppression.

Age was a non-modifiable factor that contributed to differences in viral suppression, with younger men more likely not to have suppressed virus. As there were a larger number of younger black men in the study, an age-adjusted analysis revealed important factors that could be changed. Researchers looked specifically at those modifiable factors that would decrease the prevalence ratio by 5% or more, in order to close the viral suppression gap between black and white men:

  • Having insurance coverage for ART (a 12% decrease in prevalence)
  • Having had viral load testing in the past year, a proxy for being in care (a 9% decrease in prevalence)
  • Housing stability (a 7% decrease in prevalence)
  • Income over $20,000 (a 6% decrease in prevalence)
  • Marijuana use (a 6% decrease in prevalence).

Taken together, these factors created a 23% reduction in the age-adjusted prevalence ratio of lack of viral suppression. Thus, if modifiable factors were equalised, there would no longer be a statistically significant difference in rates of viral suppression for black and white MSM in this cohort.

Conclusion

This study provides strong evidence for the presence of modifiable factors that meaningfully account for racial disparities in viral suppression. Combined, these factors completely accounted for the differences seen in viral suppression between black and white MSM. This research has clear policy implications but also points towards individual-level interventions that would be effective at bridging the racial gap in viral suppression.

“If we are serious about reducing racial disparities in HIV treatment outcomes,” Dr Knox concluded, “these results show that there are clear opportunities to target modifiable factors that would have an impact.”

References

Knox J et al. Explaining racial disparities in viral suppression among MSM living with HIV. Conference on Retroviruses and Opportunistic Infections, abstract 146, March 2020.

View the abstract on the conference website.

Watch the webcast on the conference website.