Summary
People who inject drugs (PWID) exhibit disproportionate HIV burdens in the United States (U.S.). We characterized longitudinal patterns and demographic disparities in new HIV diagnoses attributed to injection drug use (IDU) in 2008–2020. While new IDU-attributed HIV diagnoses fell by 53.9%, new HIV diagnoses remained disproportionately elevated in female (100.9/100,000), Black (258.8/100,000), and Hispanic (131.0/100,000) PWID. Despite considerable declines in new HIV diagnoses, disparities by race/ethnicity and sex persist among U.S. PWID.
Keywords: HIV incidence, HIV surveillance, people who inject drugs
Since their peak in the 1990’s, new HIV infections have declined considerably in the United States (U.S.),1 attributed to mass scale-up of antiretroviral therapy and uptake of prevention strategies like syringe services programs (SSPs), condoms, and pre-exposure prophylaxis (PrEP). However, compared with other priority populations for HIV prevention (e.g., men who have sex with men), observed declines in new HIV infections among people who inject drugs (PWID) have plateaued in recent years.1 While fewer than 7% of new HIV diagnoses in the U.S. are attributed to injection drug use (IDU),1 HIV prevalence remains elevated in PWID compared to the general population.2 Recent high-profile HIV outbreaks among PWID in the U.S. underscore the velocity with which HIV can spread in highly dense IDU networks.3
To characterize demographic disparities in new IDU-attributed HIV diagnoses between 2008 and 2020, we leveraged national HIV surveillance statistics from the U.S. Centers for Disease Control and Prevention, abstracting the annual number of new HIV diagnoses by transmission category (heterosexual contact, male-to-male sexual contact, IDU, perinatal transmission, other).1 We estimated the average (linearized) trend in new IDU-attributed HIV diagnoses over time by calculating the percent change in new diagnoses, comparing 2008 to 2020. We also estimated the annual fraction of new HIV diagnoses attributed to IDU and, separately, calculated a percent change, from 2008 to 2020, in the proportion of new diagnoses attributed to IDU. Next, to identify disparities in HIV diagnosis rates, relative differences in the number and fraction of new IDU-attributed HIV diagnoses were disaggregated by race/ethnicity (Black, Hispanic, White, other) and sex at birth (male, female).
Because national HIV surveillance statistics are population-unstandardized, trends by sex and race/ethnicity may not reflect the true burden of new HIV diagnoses among each subgroup of PWID. To address this, we divided the annual number of new HIV diagnoses attributed to IDU by the most recent (2018) PWID population size estimates from the U.S.4 This yielded an annualized rate of new IDU-attributed HIV diagnoses per 100,000 PWID, assuming that the 2018 PWID population size estimates were static between 2008 and 2020. We then repeated the above analyses using these population-standardized estimates, calculating relative differences in new IDU-attributed HIV diagnoses from 2008 to 2020—overall as well as by sex and race/ethnicity.
From 2008 to 2020, the number of new IDU-attributed HIV diagnoses declined 53.9%, from 4,419 to 2,035—corresponding to a 4.5% annualized rate of decline. The overall fraction of new HIV diagnoses attributed to IDU (relative to sexual or perinatal transmission) also fell over the observation period, from 9.4% in 2008 to 6.7% in 2020. While declines in the number of new IDU-attributed HIV diagnoses over time were comparable by sex (females: –54.9%, males: –53.2%), declines were more strongly pronounced in racial minorities, specifically Black (–74.3%) and Hispanic (–56.0%) persons, relative to White individuals (–7.1%) (Figure 1a–1b). From 2008 to 2020, observed declines in new IDU-attributed HIV diagnoses among White females (–18.5%) were offset by a 4.5% increase in new HIV diagnoses among White males over time, from 515 in 2008 to 538 in 2020 (Figure 1c).
Figure 1.
Number of new HIV diagnoses attributed to injection drug use in the United States, by (a) race/ethnicity, (b) sex at birth, and (c) race/ethnicity and sex at birth—2008 to 2020.
Table 1 presents estimated rates of IDU-attributed new HIV diagnoses per 100,000 PWID. Although standardizing new IDU-attributed HIV diagnoses to PWID population size estimates yielded similar reductions in diagnosis trends over time, the rate of new IDU-attributed HIV diagnoses was nearly twice as high in females (100.9 per 100,000) compared to males (54.3 per 100,000) in 2018. Likewise, this rate was dramatically outsized in Black (258.8 per 100,000) and Hispanic (131.0 per 100,000) populations, relative to White PWID (38.1 per 100,000). In Black populations specifically, this rate was driven principally by new IDU-attributed HIV diagnoses in Black females (23.3 per 100,000), exceeding estimates for Black males (14.9 per 100,000), White females (13.3 per 100,000), and White males (10.6 per 100,000).
Table 1.
Rates of new HIV diagnoses attributed to injection drug use per 100,000 people who inject drugs in the United States, by sex at birth and race—2008 to 2020.
|
Year
|
Total % Change (2020 vs. 2008) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018* | 2019 | 2020 | ||
|
| ||||||||||||||
| Total | 119.6 | 102.2 | 89.3 | 76.4 | 68.8 | 63.1 | 60.7 | 63.0 | 60.3 | 64.5 | 68.1 | 68.7 | 55.1 | −53.9% |
|
| ||||||||||||||
| Sex at birth | ||||||||||||||
| Female | 173.0 | 150.2 | 130.3 | 118.3 | 106.0 | 92.8 | 91.7 | 95.3 | 94.3 | 98.9 | 100.9 | 105.4 | 78.0 | −54.9% |
| Male | 97.1 | 82.0 | 72.1 | 58.8 | 53.0 | 50.7 | 47.6 | 49.3 | 46.0 | 50.0 | 54.3 | 53.2 | 45.5 | −53.2% |
| Race/ethnicity | ||||||||||||||
| Black | 752.9 | 632.1 | 540.5 | 432.1 | 384.7 | 321.9 | 289.6 | 261.2 | 250.5 | 254.3 | 258.8 | 259.8 | 193.2 | −74.3% |
| Hispanic | 236.1 | 208.6 | 178.2 | 159.9 | 141.8 | 130.5 | 130.0 | 122.6 | 121.1 | 131.6 | 131.0 | 121.9 | 103.8 | −56.0% |
| White | 34.9 | 29.8 | 27.7 | 26.4 | 23.7 | 24.6 | 25.1 | 32.7 | 29.9 | 34.1 | 38.1 | 39.6 | 32.4 | −7.1% |
| Other | 495.7 | 434.2 | 388.0 | 295.7 | 299.1 | 288.9 | 270.1 | 218.8 | 258.1 | 220.5 | 227.4 | 244.4 | 196.6 | −60.3% |
| Sex by race/ethnicity | ||||||||||||||
| Black female | 67.2 | 58.0 | 49.5 | 42.8 | 37.7 | 29.2 | 27.4 | 24.7 | 25.2 | 25.3 | 23.3 | 25.3 | 18.1 | −73.1% |
| Black male | 43.7 | 35.9 | 30.7 | 23.0 | 20.7 | 18.4 | 16.1 | 14.5 | 13.2 | 13.5 | 14.9 | 14.1 | 10.8 | −75.2% |
| Hispanic female | 21.2 | 19.3 | 14.2 | 13.9 | 12.7 | 11.2 | 12.6 | 10.7 | 11.2 | 11.0 | 11.6 | 11.6 | 9.1 | −57.3% |
| Hispanic male | 19.7 | 17.1 | 15.8 | 13.6 | 11.9 | 11.2 | 10.4 | 10.4 | 9.9 | 11.4 | 11.1 | 9.9 | 8.8 | −55.4% |
| White female | 12.8 | 10.5 | 10.2 | 10.1 | 8.8 | 9.1 | 8.9 | 11.9 | 11.0 | 12.6 | 13.3 | 13.9 | 10.4 | −18.5% |
| White male | 9.3 | 8.3 | 7.3 | 6.7 | 6.2 | 6.4 | 6.9 | 8.8 | 7.9 | 9.0 | 10.6 | 11.0 | 9.7 | +4.5% |
| Other female | 11.4 | 11.5 | 10.1 | 7.7 | 8.2 | 6.6 | 6.7 | 5.4 | 6.4 | 5.4 | 6.4 | 6.2 | 4.2 | −63.6% |
| Other male | 6.0 | 4.6 | 4.1 | 3.2 | 3.0 | 3.5 | 3.0 | 2.5 | 2.9 | 2.5 | 2.2 | 2.7 | 2.5 | −57.6% |
Notes: Estimates for the PWID population size were obtained from Bradley et al (2023), who calculated estimates for the PWID population size in the U.S. overall and by race and sex in 2018. HIV diagnoses rates were then estimated by dividing the annual number of new IDU-attributed HIV diagnoses by the PWID population size estimate obtained by Bradley et al (2023). The asterisk indicates the year in which this estimation method is most accurate. ‘Hispanic’ refers to all persons identifying as Hispanic/Latinx of any race.
Substantial progress has been made in reducing HIV diagnoses among U.S. PWID since 2008, though progress has stagnated since 2014. These declines may be explained, at least in part, by the expansion of SSPs in metropolitan areas, where HIV transmission clusters among racial minority PWID have historically emerged.5 Secular shifts in routes of opioid consumption, including transitions from injection to non-injection (i.e., snorting/smoking) modalities, may also explain declines in specific populations.6 Given these evolving population dynamics of IDU, our use of a time-invariant population size estimate for PWID, nevertheless, may have produced biased estimates of population-standardized HIV diagnosis rates. Routinely updated PWID population size estimates are needed for more accurate IDU-attributed HIV surveillance.
Demographic disparities were detected in the magnitude of declines in the number of new HIV diagnoses from 2008 to 2020. New HIV diagnoses increased in White PWID but decreased among Black and Hispanic PWID. This may be explained by the changing landscape of IDU in the U.S., where the magnitude of opioid use has skyrocketed, notably among White males, in non-metropolitan areas beyond the reach of established SSPs.5,7 However, given that male and White PWID outnumber female and non-White PWID, we estimated population-standardized rates and found that HIV diagnosis rates among female PWID and racial/ethnic minority PWID exceeded rates among male PWID and White PWID, respectively.
SSP expansion into these underserved communities, facilitated by policy change (i.e., repealing municipal/state-level SSP prohibitions) and increased funding allocations to harm reduction services, are imperative to addressing HIV burdens among PWID. Furthermore, IDU-related stigma in non-metropolitan areas, stemming in part from heightened visibility and lack of privacy/confidentiality in service-seeking,8 also poses structural barriers to accessibility of HIV prevention services for PWID outside metropolitan settings. Studies have illustrated how even in U.S. metropolitan areas that are majority Black or Hispanic, a disproportionate fraction of SSP clients are White9—a likely product of racialized stigma affecting SSP accessibility.10–12 Alternatives to SSP-based HIV prevention strategies (e.g., mobile PrEP delivery) are, thus, warranted for non-male, racial minority PWID at risk of HIV infection. HIV prevention strategies uniquely tailored to the social and geographic environments of PWID are, therefore, urgently needed to close HIV incidence disparities in the U.S.
Acknowledgements
JGR, JC, and JNP conceptualized and developed a methodology for the present analysis. JGR abstracted data, conducted formal analysis, and prepared the original manuscript draft. All authors contributed to, revised, and approved the final version of the manuscript submitted for publication.
Funding
This work was supported by the Providence/Boston Center for AIDS Research (P30AI042853), an NIH-funded program. JGR was supported by the National Institute of Mental Health (F31MH126796). JNP was supported by the Center of Biomedical Research Excellence on Opioids and Overdose, funded by the National Institute of General Medical Sciences (P20GM125507). The manuscript’s contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
Footnotes
Conflicts of Interest
JNP serves as a technical consultant for a modeling project funded by the U.S. Food and Drug Administration (U01FD00745501). The remaining authors have no conflicts of interest to disclose.
Ethical Statement
Findings from the present manuscript are derived from public access aggregated surveillance data that is not identifiable at the individual level and, therefore, does not constitute human subjects research.
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