The shifting age distribution of people with HIV using antiretroviral therapy in the United States

Abstract

Objective: To project the future age distribution of people with HIV using antiretroviral therapy (ART) in the United States, under expected trends in HIV diagnosis and survival (baseline scenario) and achieving the ending the HIV epidemic (EHE) goals of a 75% reduction in HIV diagnoses from 2020 to 2025 and sustaining levels to 2030 (EHE75% scenario).

Design: An agent-based simulation model with mathematical functions estimated from North American AIDS Cohort Collaboration on Research and Design data and parameters from the US Centers for Disease Control and Prevention's annual HIV surveillance reports.

Methods: The PEARL (ProjEcting Age, MultimoRbidity, and PoLypharmacy in adults with HIV) model simulated individuals in 15 subgroups of sex-and-HIV acquisition risk and race/ethnicity. Simulation outcomes from the baseline scenario are compared with outcomes from the EHE75% scenario.

Results: Under the baseline scenario, PEARL projects a substantial increase in number of ART-users over time, reaching a population of 909 638 [95% uncertainty range (UR): 878 449-946 513] by 2030. The overall median age increased from 50 years in 2020 to 52 years in 2030, with 23% of ART-users age ≥65 years in 2030. Under the EHE75% scenario, the projected number of ART-users was 718 348 [703 044-737 817] (median age = 56 years) in 2030, with a 70% relative reduction in ART-users <30 years and a 4% relative reduction in ART-users age ≥65 years compared to baseline, and persistent heterogeneities in projected numbers by sex-and-HIV acquisition risk group and race/ethnicity.

Conclusions: It is critical to prepare healthcare systems to meet the impending demand of the US population aging with HIV.

Figure 1:

Schematic presentation of the Projecting Age, multimoRbidity, and poLypharmacy (PEARL) model, an agent-based simulation model of people with HIV (PWH) who have initiated ART in the United States. The model is initialized with a simulated population of PWH receiving ART in year 2009, with population size estimated from the CDC’s HIV surveillance data, and age and CD4 count distributions estimated from the NA-ACCORD. ART-initiators enter the model every calendar year. We estimated the number of ART-initiators from 2010–2017 and projected the observed trends into the future (2018–2030). Simulated agents can disengage from ART, reengage with ART, or die; the probabilities of these events were estimated via mathematical functions that included calendar year, age, ART initiation date, CD4 at ART initiation, and other individual-level characteristics. Simulation projections are made from 2018–2030 in terms of population size, age-distribution and mortality in 15 subgroups of PWH who have initiated ART in the US (for an interactive map of the PEARL model that provides details on the functions that comprise the model, see PEARLHIVmodel.org)

Figure 2:

Distributions of age at ART initiation among subgroups of people with HIV using ART in the United States in 2010, 2020, and 2030. Median age in 2010, 2020 and 2030 is shown in blue, purple and red, respectively. The area under 2030’s age distribution is shaded in red for better visibility. Figure 2 footnotes: Due to the small sample size of Hispanic IDU women in the NA-ACCORD, the age distribution at ART initiation was estimated by combining NA-ACCORD data from 2010 to 2015 and this distribution was kept fixed during simulated years (2010–2030).

Figure 3a-d:

Projected age distributions, overall and among subgroups, of people with HIV using ART in the United States in 2010, 2020, and 2030 in the baseline scenario (panels a & b) and after simulating a 75% reduction in new HIV diagnoses from 2020–2025 (EHE75% - panels c & d). Median age in 2010, 2020 and 2030 is shown in blue, purple and red respectively. The area under 2030’s age distribution is shaded in red for better visibility. Black dots reflect observed data from the NA-ACCORD in year 2010, and colored lines reflect projections from the PEARL model. 3a) Overall age distribution, baseline scenario 3b) Age distributions among subgroups, baseline scenario 3c) Overall age distribution, EHE75% scenario 3d) Age distributions among subgroups, EHE75% scenario

Figure 3a-d:

Projected age distributions, overall and among subgroups, of people with HIV using ART in the United States in 2010, 2020, and 2030 in the baseline scenario (panels a & b) and after simulating a 75% reduction in new HIV diagnoses from 2020–2025 (EHE75% - panels c & d). Median age in 2010, 2020 and 2030 is shown in blue, purple and red respectively. The area under 2030’s age distribution is shaded in red for better visibility. Black dots reflect observed data from the NA-ACCORD in year 2010, and colored lines reflect projections from the PEARL model. 3a) Overall age distribution, baseline scenario 3b) Age distributions among subgroups, baseline scenario 3c) Overall age distribution, EHE75% scenario 3d) Age distributions among subgroups, EHE75% scenario

Figure 3a-d:

Projected age distributions, overall and among subgroups, of people with HIV using ART in the United States in 2010, 2020, and 2030 in the baseline scenario (panels a & b) and after simulating a 75% reduction in new HIV diagnoses from 2020–2025 (EHE75% - panels c & d). Median age in 2010, 2020 and 2030 is shown in blue, purple and red respectively. The area under 2030’s age distribution is shaded in red for better visibility. Black dots reflect observed data from the NA-ACCORD in year 2010, and colored lines reflect projections from the PEARL model. 3a) Overall age distribution, baseline scenario 3b) Age distributions among subgroups, baseline scenario 3c) Overall age distribution, EHE75% scenario 3d) Age distributions among subgroups, EHE75% scenario

Figure 3a-d:

Projected age distributions, overall and among subgroups, of people with HIV using ART in the United States in 2010, 2020, and 2030 in the baseline scenario (panels a & b) and after simulating a 75% reduction in new HIV diagnoses from 2020–2025 (EHE75% - panels c & d). Median age in 2010, 2020 and 2030 is shown in blue, purple and red respectively. The area under 2030’s age distribution is shaded in red for better visibility. Black dots reflect observed data from the NA-ACCORD in year 2010, and colored lines reflect projections from the PEARL model. 3a) Overall age distribution, baseline scenario 3b) Age distributions among subgroups, baseline scenario 3c) Overall age distribution, EHE75% scenario 3d) Age distributions among subgroups, EHE75% scenario

Figure 4a-c:

Projected number of people with HIV using ART in the United States in the baseline scenario and after simulating a 75% reduction in ART-initiators from 2020–2025 (EHE75%) a) overall, b) among White MSM, and c) among heterosexual Black/AA women 4a) Projected number of people with HIV using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4b) Projected number of White MSM using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4c) Projected number of Black/AA heterosexual women using ART in the baseline scenario (left) and in the EHE75% scenario(right), 2010–2030

Figure 4a-c:

Projected number of people with HIV using ART in the United States in the baseline scenario and after simulating a 75% reduction in ART-initiators from 2020–2025 (EHE75%) a) overall, b) among White MSM, and c) among heterosexual Black/AA women 4a) Projected number of people with HIV using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4b) Projected number of White MSM using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4c) Projected number of Black/AA heterosexual women using ART in the baseline scenario (left) and in the EHE75% scenario(right), 2010–2030

Figure 4a-c:

Projected number of people with HIV using ART in the United States in the baseline scenario and after simulating a 75% reduction in ART-initiators from 2020–2025 (EHE75%) a) overall, b) among White MSM, and c) among heterosexual Black/AA women 4a) Projected number of people with HIV using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4b) Projected number of White MSM using ART in the baseline scenario (left) and in the EHE75% scenario (right), 2010–2030 4c) Projected number of Black/AA heterosexual women using ART in the baseline scenario (left) and in the EHE75% scenario(right), 2010–2030