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US trends in HIV testing, linkage to care, and transmission
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2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta
Mark Mascolini
From 2012 through 2017, CDC-funded HIV testing dipped almost 2% yearly [1], a trend that may reflect attempts to shift payment for testing to third-party payers. But the HIV testing pace rose in 30-to-39-year-olds, people 50 or older, and transgender people. And the percentage of US residents ever tested for HIV did rise from 2011 to 2017 [2], in line with the CDC's advice that all US adolescents and adults should get tested at least once.
Other work by CDC teams traced patterns of HIV testing and incidence in subgroups including men who have sex with men (MSM) [3], transgender women [4], and people who inject drugs [5]. Other researchers reported that the HIV transmission rate was virtually 0 among people with an undetectable viral load thanks to antiretroviral therapy [6]. The overall estimated US HIV transmission rate stood at 3.5 per 100 person-years in 2015.
CDC-funded HIV test rate falling, but linkage and referral numbers up
HIV testing funded by the Centers for Disease Control and Prevention (CDC) waned almost 2% yearly in a 2012-2017 analysis [1]. But the study charted gains in linkage to care, interviews for partner services, and referral to HIV prevention services.
In 2012 the CDC launched a focused HIV prevention program that included HIV testing and promoted routine HIV screening of all adolescents and adults and targeted testing of priority populations. The analysis presented at the HIV Prevention Conference considered CDC-funded testing data from 61 local and state health departments and about 150 directly funded community-based organizations. CDC investigators used linear regression to determine estimated annual percentage change (EAPC) for outcomes of interest.
Numbers of CDC-funded HIV tests dipped from 3.4 million in 2012 to 3.1 million in 2017 to yield an EAPC of -1.8% (95% confidence interval [CI] -1.9% to -1.8%) (Table 1). The testing rate increased for certain groups, including 30-to-39-year-olds, people 50 or older, and transgender people. The rate of new positive HIV tests declined from 0.52% in 2012 to 0.48% in 2017 for an EAPC of -0.8% (95% CI -1.1% to -0.4%). But people 20 to 29 years old had more new positive tests over that period.
The proportion of newly diagnosed people linked to care within 90 days climbed steeply from 36.0% in 2012 to 66.2% in 2017 for an EAPC of 11.1% (95% CI 10.6% to 11.7%). Over the same years interviews for partner services rose almost 6% yearly (EAPC 5.9%, 95% CI 5.3% to 6.4%), while referral for HIV prevention services jumped 3% yearly (EAPC 3.1%, 95% CI 2.6% to 3.6%).
People who previously tested positive saw 2012-2017 gains in linkage to care (EAPC 13.7%, 95% CI 13.2% to 14.2%), interviews for partner services (EAPC 4.1%, 95% CI 3.5% to 4.7%), and referral to HIV prevention services (EAPC 9.4%, 95% CI 8.9% to 9.8%).
The CDC team speculated that declines in CDC-funded HIV testing over the study period may reflect efforts to transfer payment for testing to other payers to allow more CDC funding of linkage and navigation services. Improvements in linkage and referral outcomes, they suggested, may be partly explained by improving data completeness over the study period.
Ever-tested for HIV rate climbing but still below 50% in US
Despite 2006 CDC advice that all 13- to 64-year-olds should get tested for HIV at least once [7], the US ever-tested rate still stands well below 50%, according to a 2011-2017 CDC analysis [2] (Table 2). But proportions of people ever tested and tested in the past 12 months climbed significantly over the study period.
The CDC issued revised recommendations for HIV testing in 2006, calling for testing at least once in everyone 13 to 64 years old, and for yearly testing for high-risk groups such as MSM, people who inject drugs, and their sex partners [7]. This analysis explored data from the nationally representative Behavioral Risk Factor Surveillance System, focusing on 18- to 64-year-olds in the period 2011-2017 who self-reported ever getting tested for HIV or getting tested in the past 12 months.
The overall ever-tested rate leapt significantly from 42.9% in 2011 to 45.9% in 2017 (P < 0.001). In 2017 three groups were more likely to be ever tested than counterpart comparison groups: blacks (68.6%), 35- to 44-year-olds (58.4%), and females (48.8%). Utah had the lowest ever-tested rate in 2017, with about one quarter getting an HIV test (26.5%), while three quarters got tested in Washington, DC, the highest rate (75.5%).
The proportion of people tested for HIV in the past 12 months inched up from 13.2% in 2011 to 14.8% in 2017, but that gain was statistically significant (P < 0.001). HIV testing in the past 12 months proved more likely in blacks (34.1%), 25- to 34-year-olds (22.3%), and females (15.6%) than in comparison groups. Utah had the lowest past-12-month testing rate (6.5%), while Washington, DC had the highest (40.7%).
A decade after the 2006 CDC recommendations [7], the CDC team noted, fewer than half of this nationally representative US sample self-reported ever getting tested for HIV, and only about 15% got tested in the past year. The researchers called for further work to determine how to encourage the general US population to get tested for HIV.
HIV testing rising in US MSM, while new infections drop
CDC-funded HIV testing of MSM rose 4.5% yearly from 2012 through 2017 but fell in the youngest age group, according to analysis of 1.7 million US tests [3]. Over the same period, the new HIV-diagnosis rate dropped 5% yearly in this population.
CDC investigators who conducted this study noted that MSM make up an estimated 2% of the US population, yet in 2016 they accounted for 70% of new HIV diagnoses. The CDC targets MSM as a group at high risk for HIV infection with strategies including HIV testing, linkage to care, and partner services.
The analysis involved 1,670,899 HIV tests of MSM with risk behavior data from 61 CDC-funded health departments and about 150 community-based organizations. CDC researchers used linear regression to figure estimated annual percentage change (EAPC) for several testing and referral outcomes.
Numbers of HIV tests in the MSM study group rose from 251,640 in 2012 to 305,061 in 2017, almost a 5% per year increase (EAPC 4.5%, 95% CI 4.4% to 4.6%, P < 0.001). But the new testing rate dropped in MSM 18 years old or younger and in men 40 to 49 years old. The new-HIV diagnosis rate slipped 5.1% yearly, from 3.1% in 2012 to 2.5% in 2017, a significant drop (P < 0.001). Table 3 compares major findings in MSM with those in transgender women and people who inject drugs.
Among men with newly diagnosed HIV, the rate of linkage to care within 90 days improved 8.4% yearly from 43.3% in 2012 to 71.1% in 2017 (P < 0.001). Referrals for partner services climbed from 78.0% in 2012 to 86.4% in 2017, a 1.6% annual uptick (P < 0.001). Over the same period interviews for partner services rose from 44.0% to 61.8%, an annual gain of 4.8% (P < 0.001). Referrals for HIV prevention services jumped from 61.5% in 2012 to 76.3% in 2017, a 3.5% annual improvement (P < 0.001).
The investigators noted that gains in linkage to care, referrals for HIV prevention services, and provision of partner services may partly reflect improvements in data completeness. Declining HIV testing in young MSM suggested to the CDC team that this group needs more targeted HIV testing.
HIV testing up in US transgender women but new HIV rate flat
HIV testing rates among US transgender women rose more than 10% yearly from 2012 through 2017, according to results of a large CDC analysis [4]. But the HIV diagnosis rate waned only slightly over the study period.
Growing numbers of people identify as transgender women in the United States. CDC data indicate that transgender women have the highest HIV rate in the country compared with other gender groups. Much work shows that transgender women do not access HIV care as often as other groups. Because these findings come from small or geographically limited samples, the CDC undertook this analysis of a broader transgender woman population.
The CDC team defined transgender women as those assigned male sex at birth who currently self-identify as female or male-to-female transgender. The researchers analyzed data from this population collected over 2012-2017 from 61 CDC-funded local and state health departments and about 150 community-based organizations. After charting changes in HIV testing, diagnosis, and referral patterns, they used linear regression to calculate estimated annual percent change (EAPC) in these outcomes.
The 2012-2017 sample included 58,310 HIV tests in transgender women. Numbers of tests rose more than 10% yearly (EAPC 10.6%, 95% CI 9.9% to 11.3%, P < 0.001), from 8962 in 2012 to 12,758 in 2017. That gain could partly reflect a growing number of people identifying as transgender women. The new HIV diagnosis rate dropped significantly over the study period (EAPC -7.0%, 95% CI -10.6% to -3.3%, P < 0.001), but the overall decline was small, from 2.3% in 2012 to 2.1% in 2017. Table 3 compares major findings in transgender women with those in MSM and people who inject drugs.
Among newly diagnosed transgender women, linkage to medical care within 90 days almost doubled from 35.6% in 2012 to 65.4% in 2017 (EAPC 5.0%, 95% CI 1.8% to 8.3%, P < 0.001). Interviews for partner services more than doubled over those years, from 21.0% to 53.5% (EAPC 5.3%, 95% CI 1.6% to 9.1%, P < 0.001). But the rate of referral to HIV prevention services changed little, from 61.0% to 63.9% (EAPC 1.1%, 95% CI -1.7% to 4.0%, P = 0.455).
The CDC investigators cautioned that improving rates of linkage to care and interviews for partner services may partly reflect more complete data collection over the years. But they stressed that these rates remain below national objectives. They proposed that "expanding gender-sensitive HIV prevention and care may help remove social and structural barriers to services, promote sexual health, and reduce the disproportionate burden of HIV among transgender women."
HIV testing flat in drug injectors, linkage and referral numbers up
Numbers of HIV tests in people who inject drugs changed little from 2012 through 2017, while new HIV infections inched up [5]. Linkage to HIV care rose sharply across the study years, as did interviews for partner services.
People who inject drugs, including MSM who inject drugs, account for about 10% of new HIV diagnoses in the United States. The CDC recommends annual HIV testing for these groups and for their sex partners [7]. To chart trends in HIV testing, new diagnoses, and referrals, CDC investigators analyzed data from 61 CDC-funded local and state health departments and approximately 150 directly funded community-based organizations. They used linear regression to calculate estimated annual percentage change (EAPC) in outcomes measured.
The study involved 529,349 HIV tests in people who inject drugs, representing 2.7% of the total 19.7 million tests analyzed. From 2012 through 2017 the number of HIV tests in drug injectors hardly budged, falling nonsignificantly from 88,701 to 88,037 (EAPC -0.93%, 95% CI -1.09% to 0.77%). Over the same years rates of newly diagnosed HIV in these people edged upward from 0.7% to 0.8%, a small but statistically significant hop (EAPC 4.15%, 95% CI 2.41% to 5.53%). Table 3 compares these outcomes and others in people who inject drugs, MSM, and transgender women.
Rates of linkage to care within 90 days of HIV diagnosis jumped from 35.8% in 2012 to 57.0% in 2017, an almost 7% yearly gain (EAPC 6.84%, 95% CI 5.17% to 8.54%). Rates of interviews for partner services also climbed dramatically, from 29.5% in 2012 to 52.4% in 2017 (EAPC 5.19%, 95% CI 3.39% to 7.02%). Referral for HIV prevention services rose through the study period, from 55.5% in 2012 to 69.8% in 2017 (EAPC 2.58%, 95% CI 1.16% to 4.02%).
The researchers stressed that solid gains in linkage to care and referrals in 2012-2017 still leave people who inject drugs well short of national goals. They reminded colleagues that increased testing and linkage to care and partner services could limit HIV transmissions in this high-risk group.
HIV transmission lowest with viral suppression, highest with acute infection
People with an undetectable viral load thanks to antiretroviral therapy (ART) had a virtually nil HIV transmission rate in 2015, according to an updated model fashioned by the CDC [6]. In contrast, people unaware of their acute HIV infection had a 223-fold higher risk of HIV transmission.
To estimate HIV transmission rates in the United States by transmission category and position along the continuum of care, CDC investigators updated a published model, the Progression and Transmission of HIV/AIDS (PATH 2.0) model [8]. Updates involved expanding the model to include people who inject drugs and accounting for recent data from the National HIV Surveillance System and the National HIV Behavioral Surveillance System. The CDC team began the model in 2006 and ran it through 2015.
For 2015 the model estimated the overall US HIV transmission rate at 3.51 per 100 person-years, a figure close to the National HIV Surveillance System estimate of 3.43 per 100 person-years. Average annualized transmission rate proved lowest for virally suppressed people on ART, 0.07 per 100 person-years (Table 4).
Estimated transmission rates were successively higher for people in care for HIV but not virally suppressed (5.65 per 100 person-years), people aware of their HIV but not in care (5.98 per 100), people unaware of their nonacute HIV infection (8.89 per 100), and people unaware of their acute HIV infection (15.64 per 100). Compared with the ART-treated virally suppressed group, these other four groups were 81, 85, 127, and 223 times more likely to transmit HIV.
Of the estimated 38,546 new HIV infections in 2015, 71% involved transmissions by MSM, 19.8% by people who inject drugs, and 9.7% by heterosexuals. HIV transmission rate was highest for men who inject drugs (4.82 per 100 person-years), followed by MSM (4.42), women who inject drugs (3.06), heterosexual men (2.03), and heterosexual women (0.79).
References
1. Wang G, Belcher L, Song W, Heritage J, Smith J. HIV testing, diagnosis, and linkage to care and prevention services among persons tested in CDC-funded sites, 2012-2017. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5554.
2. Patel D, Johnson C, Krueger A, DiNenno E, Belcher L, Harris N. National and state-level HIV testing trends, 2011-2017: progress and challenges. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5376.
3. Raiford J, Wang G, Stein R, Song W, Belcher L. HIV testing, diagnosis, and linkage to care and prevention services among MSM tested in CDC-funded sites, 2012-2017. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5599.
4. Mulatu M, Song W, Wang G, Keatley J, Kudon HZ, Wan C. HIV testing, diagnosis, and linkage to care and prevention services among transgender women tested in CDC-funded sites, 2012-2017. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5626.
5. Rao S, Song W, Essuon A, Mulatu M, Heitgerd J. HIV testing, diagnosis, and linkage to care and prevention services among persons who inject drugs tested in CDC-funded sites, 2012-2017. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5565.
6. Li Z, Chen YH, Gopalappa C, Farnham P, Sansom S. HIV transmission along the continuum of care - United States, 2016. 2019 National HIV Prevention Conference, March 18-21, 2019, Atlanta. Abstract 5419.
7. Branson BM, Handsfield HH, Lampe MA, et al. Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR. September 22, 2006 / 55(RR14);1-17. https://www.cdc.gov/mmwr/preview/mmwrhtml/Rr5514a1.htm
8. Gopalappa C, Farnham PG, Chen YH, Sansom SL. Progression and transmission of HIV/AIDS (PATH 2.0). Med Decis Making. 2017;37:224-233. https://www.ncbi.nlm.nih.gov/pubmed/27646567
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