Major disparities persist in lifetime risk of HIV diagnosis in the US

The lifetime risk of being diagnosed with HIV in the US has decreased overall during the past decade, falling to 1 in 99, according to a study from the Centers for Disease Control and Prevention (CDC) presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2016) this week in Boston. The risk varies widely among population sub-groups, however, and half of black gay and bisexual men are likely to become infected if current trends persist.

Kristen Hess and colleagues used HIV diagnosis and death rates from the National HIV Surveillance System, National Center for Health Statistics and population census data to estimate the lifetime risk of being diagnosed with HIV, looking at sub-groups based on sex, age and race/ethnicity, as well as by state. These are the first-ever comprehensive national estimates of the lifetime risk of HIV diagnosis for several key populations at risk, according to the CDC.

“These estimates are a sobering reminder that gay and bisexual men face an unacceptably high risk for HIV – and of the urgent need for action.” Dr Eugene McCray

The number of HIV diagnoses and deaths between 2009 and 2013 were used to calculate the probability of an HIV diagnosis at a given age. The lifetime risk estimate is the cumulative probability of being diagnosed with HIV from birth to death, assuming diagnosis rates remain constant. The new estimates were compared to findings from an analysis done in 2004-2005.

The researchers found that the overall lifetime risk of an HIV-positive diagnosis was lower than it was a decade ago, falling from about 1 in 78 during 2004-2005 to 1 in 99 during 2009-2013.

But “major disparities persist” across sub-groups, Hess told a CROI press conference.

Across all racial/ethnic groups, the lifetime risk of HIV diagnosis was higher for men (1 in 64) than for women (1 in 227).

African Americans had the highest lifetime risk of any racial/ethnic group, 1 in 20 for black men and 1 in 48 for black women. Estimated diagnosis rates among Hispanics/Latinos (1 in 48 for men and 1 in 227 for women) and Pacific Islanders (1 in 82 for men and 1 in 385 for women) were lower, but still considerably higher than the risk for white people (1 in 132 for men and 1 in 880 for women) or Asian Americans (1 in 174 for men and 1 in 883 for women). Native American men had about the same risk as white men (1 in 129), while Native women had a much higher risk than white women (1 in 399).

The analysis confirmed that men who have sex with men are most heavily affected by the HIV epidemic, with a 1 in 6 chance of ever being diagnosed – nearly 80 times more likely than heterosexual men.

Breaking the categories down further, black gay and bisexual men had the highest risk of any subgroup, with 1 in 2 expected to be diagnosed over a lifetime. For Latino gay men the risk was 1 in 4 and for Pacific Islander men it was 1 in 7. Whites (1 in 11), Native Americans (1 in 12) and Asians (1 in 14) had the lowest lifetime likelihood of diagnosis among gay men.

People who inject drugs also had a much higher lifetime risk than the population as a whole, 1 in 36 for men and 1 in 23 for women. For black drug injectors the risk was 1 in 9 for men and 1 in 6 for women. Unlike the population overall, in this sub-group women had a higher risk of HIV diagnosis than men.

Heterosexuals who did not report injection drug use had a much lower risk of diagnosis (1 in 473 for men and 1 in 241 for women). But again, the likelihood was higher for African Americans (1 in 86 for men and 1 in 49 for women) while whites had very low lifetime risk (1 in 2514 for men and 1 in 1083 for women).

The researchers did not report separate figures for lesbians or for transgender men or women.

Looking at data by state, lifetime diagnosis risk ranged from a low of 1 in 670 in North Dakota to a high of 1 in 49 in Maryland. People living in the southeast were more likely to be diagnosed than people in other regions, while those in the northwest were least likely. The highest risk of all was seen in Washington, DC, at 1 in 13.

Looking at “age-conditional” risk of HIV diagnosis, or the likelihood during the next 10 years, risk was highest for gay men at age 20 (1 in 15) compared with those at age 30 (1 in 21), age 40 (1 in 26) and age 50 (1 in 55). However, among men who inject drugs, the risk increased with age, perhaps indicating late diagnosis.

“Lifetime risk may be a useful tool to more effectively communicate the risk of HIV to the general public” and “can help to highlight the severe disparities”, the researchers concluded.

“As alarming as these lifetime risk estimates are, they are not a foregone conclusion. They are a call to action,” Dr Jonathan Mermin, director of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and Tuberculosis Prevention said in a CDC press release. “The prevention and care strategies we have at our disposal today provide a promising outlook for future reductions of HIV infections and disparities in the US, but hundreds of thousands of people will be diagnosed in their lifetime if we don't scale up efforts now.”

“These estimates are a sobering reminder that gay and bisexual men face an unacceptably high risk for HIV – and of the urgent need for action”, added Dr Eugene McCray, director of CDC’s Division of HIV/AIDS Prevention. “If we work to ensure that every American has access to the prevention tools we know work, we can avoid the outcomes projected in this study.”