Table 1.
Input parameters for a model of a 12-month adherence intervention in youth with HIV in the United States
| Parameter | Base case value | Source |
|---|---|---|
| Cohort characteristics | ||
| Age, mean (SD) | 19.5 (3.6) | [21] |
| Male/Female sex, % | 79/21 | [69] |
| CD4 at model start, cells/µL, mean (SD) | 545 (228) | [21] |
| HIV RNA setpoint off ART | [22] | |
| Mean log10 copies/mL (copies/mL) | 5.22 (165,800) | |
| Distribution, % of cohort | ||
| > 100,000 copies/mL | 25.1 | |
| 30,001–100,000 | 42.0 | |
| 10,001–30,000 | 20.9 | |
| 3,001–10,000 | 5.6 | |
| 501–3,000 | 6.4 | |
| 0–500 | 0 | |
| Baseline ART adherencea and virologic suppression | ||
| Adherence to ART ≤ 25 years, % of cohort | Modeled cohortb | |
| Adherence > 90% | 20 | |
| Adherence 81–90% | 14 | |
| Adherence 71–80% | 9 | |
| Adherence 61–70% | 7 | |
| Adherence ≤ 60% | 50 | |
| Adherence to ART > 25 years, % of cohort | Modeled cohortb | |
| Adherence > 90% | 34 | |
| Adherence 81–90% | 12 | |
| Adherence 71–80% | 6 | |
| Adherence 61–70% | 5 | |
| Adherence ≤ 60% | 43 | |
| ART efficacy (VL < 50 copies/mL at 48 weeks)c, % | ||
| > 95% adherence | 96.4 | [25–28] |
| < 57% adherence | 0 | [29] |
| Late virologic failure, range by adherence level, monthly probability, % | 0.2–18 | [30–32] |
| Loss to follow-up | ||
| Loss to follow-up after 12 months, range by adherence level, monthly probability | 0.7–2 | [21, 33–35] |
| Returning to care, monthly probability | 0.015 | [36] |
| Opportunistic infections off ART, range by CD4 count, monthly probabilityd | [70] | |
| Pneumocystis pneumonia | 0.0004–0.0084 | |
| Mycobacterium avium complex | 0.0001–0.0047 | |
| Toxoplasmosis | 0.0001–0.0007 | |
| Cytomegalovirus | 0.0001–0.0082 | |
| Fungal infection | 0.0001–0.0032 | |
| Other opportunistic infection | 0.0006–0.0116 | |
| Chronic AIDS death off ART, range by OI history, monthly probabilitye | [70] | |
| CD4 > 500 | 0.00025 | |
| CD4 351–500 | 0.00583 | |
| CD4 201–350 | 0.00092–0.02696 | |
| CD4 101–200 | 0.00250–0.03303 | |
| CD4 51–100 | 0.00341–0.03254 | |
| CD4 0–50 | 0.01472–0.06900 | |
| Non-HIV-related death, by age, monthly probability | [71, 72] | |
| 13–14 years | 0.00001–0.00002 | |
| 15–19 | 0.00002–0.00004 | |
| 20–24 | 0.00003–0.00006 | |
| 25–29 | 0.00004–0.00007 | |
| 30–39 | 0.00005–0.00012 | |
| 40–49 | 0.00011–0.00025 | |
| 50–59 | 0.00027–0.00068 | |
| 60–69 | 0.00071–0.00175 | |
| 70–79 | 0.00181–0.00416 | |
| 80–99 | 0.00433–0.01320 | |
| HIV transmissions | ||
| HIV transmissions, range by VL, per 100PY | [20, 37, 38] | |
| > 100,000 copies/mL | 16.5 | |
| 10,001–100,000 | 14.8 | |
| 3,001–10,000 | 7.6 | |
| 501–3,000 | 3.8 | |
| 21–500 | 0.3 | |
| 0–20 | 0 | |
| Costs (USD 2018) | ||
| Adherence intervention, monthly | 100 | Modeled intervention |
| Routine care, range by CD4 cell count, monthlyf | 260–1,150 | [40–42] |
| Opportunistic infection | 7,100–16,700 | [40–42] |
| ART, monthly | 2,670 | [43] |
SD standard deviation, HVL HIV viral load (HIV RNA), ART antiretroviral therapy, VS virologic suppression, USD United States dollars, PY person-years
aAdherence is measured as percent of pills taken
bSee Supplemental Methods for details
cEfficacy between 57 and 95% adherence is exponentially interpolated (Supplemental Methods)
dA multiplier of 0.2 is applied for patients on ART [73, 74]
eA multiplier of 0.1 is applied for patients on ART [73, 74]
fHigher CD4 counts are associated with LOWER routine care costs
Additional details of inputs may be found in the Supplemental Methods