Table 1.
Input Parameters for a Model of Frequent HIV Screening for High-risk Young Men Who Have Sex with Men in the United States
| Population characteristics | Value | Range for sensitivity analysis | Source |
|---|---|---|---|
| Initial age (years) | 15 | 14–30 | [3, 4] |
| Male birth sex (%) | 100 | 100 | |
| HIV prevalence at age <15 years (%) | 0 | 0–6.8 | |
| Annual HIV incidence by age, rate/100PY | |||
| 15–17 years | 6.41 | 0.64–12.82 | [4] |
| 18–22 | 3.29 | 0.33–6.58 | [3] |
| ≥23 | 0.91 | 0.09–1.82 | [12] |
| Current HIV screening practice (annual probability of HIV detection by age) (%) | |||
| 14–15 years | 0.7 | 0.4–3.5 | [8, 9] |
| 16–17 | 1.0 | 0.5–5 | [8, 9] |
| 18–20 | 10.3 | 5.2–51.5 | [9, 10] |
| 21–24 | 8.9 | 4.5–44.5 | [9, 10] |
| 25–29 | 7.6 | 3.8–38.0 | [9, 11] |
| 30–39 | 6.5 | 3.3–32.5 | [9, 11] |
| ≥40 | 5.9 | 3.0–29.5 | [9, 11] |
| Mean CD4 at infection, cells/µL | 667 | 200–800 | [5] |
| Mean HIV RNA at infection, copies/mL | >100 000 | - | [13] |
| Screen characteristics a | |||
| Sensitivity (%) | 99.6 | 50–100 | [14] |
| Specificity (%) | 99.7 | 50–100 | [14] |
| Probability of screen offer and acceptance (%) | 80 | 25–100 | [15, 16] |
| Probability of result return (%) | 97 | 50–100 | [17, 18] |
| Probability of linkage to care (%) | 76 | 25–100 | [19] |
| HIV screening program costs (USD 2018) | |||
| HIV screen | 38.00 | 17.96–71.84 | [20] |
| Completed reactive testb | 76.42 | 36.12–144.46 | [20, 21] |
| Antiretroviral therapy (range, 1 st through 6 th available regimen) | |||
| Efficacy (%)c | 93–81 | - | [22–24] |
| Cost/month (USD 2018)d | 2290–3780 | 0.5–2.0x base case | [25, 26] |
| Loss to follow-up (rate/100PY) | |||
| Adherence >95% | 0.1 | - | [27] |
| Adherence <50% | 84.5 | 41.5–498.6 | [27] |
| Return to care (rate/100PY) | 18.1 | 18.1–100 | [28] |
| Onward transmission (rate/100PY), by disease stage and HIV RNA | |||
| Acute infection, off ARTa | 86.1 | 0–262 | [13, 29, 30] |
| Acute infection, on ARTa | 9.5 | 0–19 | [29–31] |
| >100 000 copies/mL | 16.5 | 0–33 | [29] |
| >10 000–100 000 copies/mL | 14.8 | 0–30 | [29] |
| >3000–10 000 copies/mL | 7.6 | 0–33 | [29] |
| >500–3000 copies/mL | 3.8 | 0–16 | [29] |
| ≤500 copies/mLe | 0.3 | 0–0.6 | [29] |
Abbreviations: ART, antiretroviral therapy; PY, person-year; USD 2018, 2018 US dollars.
a Screen sensitivity and specificity were the same for both the acute and chronic phase. The duration of acute infection is 2 months in the base case (sensitivity analysis range: 0–6 months).
b Includes costs of confirmatory testing and counseling.
c Antiretroviral efficacy is defined as the rate of suppression of HIV RNA <400 copies/mL at 48 weeks.
d ART costs were based on averages for integrase-based regimens: $2290; protease inhibitor-based regimens: $2670; and salvage regimens: $3780.
e Although recent data from adults suggest 0 transmissions occurring from people with HIV with plasma HIV RNA durably suppressed to <50 copies/ml, we lack data to apply the same zero risk to adolescents and young adults, who often have less consistent virologic suppression. We therefore apply a transmission risk of 0.3/100PY to the lowest modeled RNA stratum based on the available data.
Additional details of inputs, including quality-of-life utility weights, may be found in Supplementary Table 2 [32, 33].