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. Author manuscript; available in PMC: 2016 Dec 1.
Published in final edited form as: J Acquir Immune Defic Syndr. 2015 Nov 1;70(3):e84–e93. doi: 10.1097/QAI.0000000000000783

TABLE 2.

Model Parameter Values and Data Sources

Epidemiologic and Intervention Effect Inputs Base Value Range Source
Distribution of cohort by selected CD4 categories
<250 cells/µL 0.40 0.20–0.50 Trial data
<350 cells/µL 0.60 0.40–0.70
<500 cells/µL 0.80 0.60–0.90
Base Value Below
CD4 Threshold* 		Range Base Value Above
CD4 Threshold* 		Range Sources
TB disease prevalence at baseline
  CD4 250 cells/µL 0.11 0.05–0.16 0.05 0.02–0.07 3,29,45
  CD4 350 cells/µL 0.10 0.05–0.15 0.03 0.02–0.05 3,29,45
  CD4 500 cells/µL 0.09 0.04–0.13 0.01 0.00–0.02 3,29,45
TB screening†
  Proportion correctly identified with TB disease at
baseline
  CD4 250 cells/µL 0.96 0.79–0.98 0.83 0.63–0.95 Imputed from45
  CD4 350 cells/µL 0.95 0.78–0.97 0.80 0.65–0.94
  CD4 500 cells/µL 0.90 0.73–0.92 0.75 0.60–0.85
  Proportion not requiring anti-TB treatment at baseline
  CD4 250 cells/µL 0.98 0.80–1.00 0.99 0.80–1.00 Assumption
  CD4 350 cells/µL 0.98 0.80–1.00 0.99 0.80–1.00
  CD4 500 cells/µL 0.99 0.80–1.00 1.00 0.80–1.00
TST positivity
  CD4 250 cells/µL
  Proportion TST-positive with active TB 0.52 0.42–0.62 0.73 0.59–0.87 31,33
  Proportion TST-positive without active TB 0.17 0.15–0.23 0.30 0.24–0.36 13,14,16,32,34
TB incidence rates‡
  CD4 200 cells/µL
  TST-positive PLHIV 0.18 0.07–0.49 0.03 0.02–0.05 Trial data
  TST-negative PLHIV 0.03 0.01–0.08 0.01 0.01–0.02
  PLHIV (TST status unknown) 0.07 0.03–0.18 0.02 0.01–0.03
Mortality rates‡
  CD4 200 cells/µL, TB-negative PLHIV
  TST-positive 0.05 0.01–0.36 0.02 0.01–0.04 Trial data
  TST-negative 0.05 0.02–0.12 0.01 0.00–0.02
  TST status unknown 0.05 0.02–0.18 0.01 0.01–0.02
Base Value
on ART 		Range Base Value
Not
on ART 		Range Sources
Mortality rates∥
  TB-positive PLHIV
  Prevalent cases identified at baseline 0.05 0.01–0.20 0.15 0.05–0.30 46–48
  Incorrectly classified for active TB at baseline
  False negatives—IPT/delayed TB treatment 0.27 0.05–0.35 0.35 0.10–0.40 Supplementary§ Digital Content
  False negatives—No IPT/delayed TB treatment 0.27 0.05–0.35 0.35 0.10–0.40 Supplementary§ Digital Content
  False positives—TB treatment 0.02 0.01–0.15 0.01 0.00–0.10 49–53
Base Value Below
CD4 Threshold* 		Range Base Value Above
CD4 Threshold* 		Range Source
Reduction in TB incidence due to ART initiation at
higher CD4 compared to threshold CD4 200 cells/µL‡
  CD4 250 cells/µL 0.21 0.04–0.32 0.20 0.04–0.30 1,54
  CD4 350 cells/µL 0.26 0.05–0.38 0.50 0.10–0.75 1,14,54–59
  CD4 500 cells/µL 0.35 0.07–0.52 0.65 0.13–0.97 1,54,56,57,60
Reduction in mortality due to ART initiation at higher
  CD4 compared to threshold CD4 200 cells/µL‡
  CD4 250 cells/µL 0.22 0.04–0.34 0.18 0.04–0.27 53,61
  CD4 350 cells/µL 0.28 0.06–0.41 0.54 0.11–0.81 49–51,53,61
  CD4 500 cells/µL 0.44 0.09–0.66 0.71 0.14–1.07 53,61
Reduction in TB incidence after provision of ART‡
  CD4 250 cells/µL 0.59 0.12–0.86 — — Supplementary§ Digital Content
  CD4 350 cells/µL 0.56 0.13–0.88 — —
  CD4 500 cells/µL 0.49 0.10–0.74 — —
Reduction in mortality after provision of ART‡
  CD4 250 cells/µL 0.62 0.12–0.93 — — Supplementary§ Digital Content
  CD4 350 cells/µL 0.58 0.15–0.87 — —
  CD4 500 cells/µL 0.45 0.09–0.68 — —
Reduction (increase) in TB incidence after provision
of IPT‡
  CD4 200 cells/µL, 6-mo course
  TST-positive 0.21 0.00–0.30 0.21 0.00–0.30 Trial data
  TST-negative 0.05 0.00–0.10 0.05 0.00–0.10 Trial data
  TST status unknown 0.16 0.00–0.20 0.12 0.00–0.20 Trial data
  CD4 200 cells/µL, 36-mo course
  TST-positive 0.77 0.39–0.91 0.88 0.74–0.95 Trial data
  TST-negative 0.31 0.58–0.10 0.30 0.23–0.35 Trial data
  TST status unknown 0.41 0.23–0.42 0.56 0.47–0.61 Trial data
Reduction (increase) in mortality after provision of IPT‡
  CD4 200 cells/µL, 6-mo course
  TST-positive 0.09 0.00–0.15 0.09 0.00–0.15 Trial data
  TST-negative 0.00 0.00–0.01 0.00 0.00–0.00 Trial data
  TST status unknown 0.02 0.01–0.04 0.04 0.00–0.10 Trial data
  CD4 200 cells/µL, 36-mo course
  TST-positive 0.06 0.10–0.00 0.77 0.63–0.87 Trial data
  TST-negative 0.71 1.08–0.38 0.47 0.64–0.34 Trial data
  TST status unknown 0.56 0.99–0.22 0.13 0.08–0.20 Trial data
Cost Inputs∥ Base Value Range Source
Annual ART
  Clinical care and laboratory services 371 186–557 25
  Antiretroviral drugs 230 115–345 62
  Total ART 601 301–902
TB treatment
  Pharmacist observation (10 minutes daily) 322 — 27
  Standard 182 d DOTS treatment 10 — 27
  Total TB treatment 332 166–498 27
IPT
  Nurse time (15 min per visit) 2.66 — 27
  Isoniazid per month 0.50 — 27
  Pyridoxine (B6) per month 0.17 — 27
  Total 6-mo IPT 20 10–29
  Total 36-mo IPT 117 59–176
TST
  Protein purified derivative per dose 6.50 — 12
  Nurse time and medical supplies 4.60 — Trial data
  Required infrastructure investments per person 2.03 — 36
  Total TST 13 7–20
Hospitalization
  Inpatient cost per day 190 — 36
  Total hospitalization for TB (21 d) 3999 1999–5998
  Total hospitalization for IPT toxicity (10 d) 1904 952–2856

TB disease prevalence at baseline CD4 250 cells/µL, CD4 350 cells/µL, and CD4 500 cells/µL.

*

PLHIV below the specified threshold were assumed to also receive ART; PLHIV above the specified threshold did not receive ART over the period.

†

Data imputed for CD4 <250 and CD4 <500.

‡

Calculated using intent-to-treat trial data and estimates from the published literature. All values presented are per annum; rate reductions averaged over 36 months.

§

Detailed derivation of these estimates can be found in the Supplementary Digital Content, http://links.lww.com/QAI/A727.

∥

All costs are reported per patient and have been inflated to 2010 US dollars using the Medical Care Consumer Price Index provided by the US census bureau.