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. Author manuscript; available in PMC: 2010 Sep 1.
Published in final edited form as: J Acquir Immune Defic Syndr. 2009 Sep 1;52(1):106–113. doi: 10.1097/QAI.0b013e3181a4f9c4

Table 2.

Estimates for Model Variable

Variable Base Case Range Source
Demographic variables
     Age at presentation (mean ± SD) 33±9 Holmes29, Badri47
     Male 60% 50–70% Holmes29, Badri28, Orrell21
     CD4 at presentation, cells/µl (mean ±
     SD)		 307±227 Holmes29, Badri47
     Viral load at presentation, log
     copies/ml (mean ± SD)		 5.0± 0.8 Badri48
Disease Progression Variables
     Decline in CD4 (cells/µl/mo), viral
     load >105 		Holmes29, Mellors49,
Rodriguez50, PLATO51
    Baseline CD4 >500 cells/µl 5.9 ± 50%
    Baseline CD4 351–500 cells/µl 3.8 ± 50%
    Baseline CD4 201–350 cells/µl 2.6 ± 50%
    Baseline CD4 <200 cells/µl 2.0 ± 50%
     Decline in CD4 (cells/µl/mo), viral
     load 103–105 		Holmes29, Mellors49,
Rodriguez50, PLATO51
    Baseline CD4 >500 cells/µl 3.9 ± 50%
    Baseline CD4 351–500 cells/µl 2.6 ± 50%
    Baseline CD4 201–350 cells/µl 1.7 ± 50%
    Baseline CD4 <200 cells/µl 1.3 ± 50%
Monthly probability of developing severe
opportunistic diseases (%), by CD4		 <50
cells/µl 		51–200
cells/µl 		201–350
cells/µl 		>350
cells/µl 		Holmes29
     Oral candidiasis 3.50% 2.04% 1.26% 0.57%
     Chronic diarrhea 2.00% 0.49% 0.18% 0.00%
     Esophageal candidiasis 1.46% 0.34% 0.09% 0.06%
     Wasting syndrome 1.29% 0.23% 0.02% 0.00%
     Severe bacterial 1.15% 0.04% 0.03% 0.00%
     Pulmonary TB 1.15% 0.71% 0.47% 0.11%
     Extrapulmonary TB 0.98% 0.47% 0.18% 0.05%
     PCP 0.67% 0.05% 0.02% 0.00%
  CMV 0.52% 0.07% 0.02% 0.00%
  Cryptococcal meningitis 0.52% 0.05% 0.00% 0.00%
Risk of death Badri28
  CD4 <50 cells/µl 2.1%/mo
  CD4 51–200 cells/µl 1.7%/mo
  CD4 201–350 cells/µl 1.1%/mo
  CD4 >350 cells/µl 0.8%/mo
Additional risk of death from severe
opportunistic disease		 Goldie9
  CD4 <50 cells/µl 7.69%/mo
  CD4 51–200 cells/µl 4.48%/mo
  CD4 201–350 cells/µl 0.66%/mo
Risk of virologic failure See Table 1
Harm from discontinuation of a non-
suppressive regimen		 Deeks52
  Drop in CD4, cells/µl 128
  Rise in viral load set point, log
  copies/ml		 0.8
Risk of regimen change or
discontinuation due to toxicity, %/mo
     AZT + 3TC + ABC 0.3 0.1–0.5 DART14, Munderi53
     AZT + 3TC + NVP or EFV 0.5 0.3–0.7 Orrell25, Boulle39
     TDF + 3TC + LPV/r 0.3 0.1–0.5 Amoroso54, Calmy40
     TDF + 3TC + DNV/r 0.5 0.3–0.7 Madruga16 Clotet17
Utilization and Cost Variables
  Annual inpatient cost (2007USD) Badri30, Govender55,
Cleary56, Thomas57
     No AIDS on HAART 255 230–282
     AIDS on HAART 483 386–596
     No AIDS off HAART 887 839–939
     AIDS off HAART 3,632 3,304–
3,985
  Annual Outpatient cost Badri30, Govender55,
Cleary56
     No AIDS on HAART 316 305–328
     AIDS on HAART 276 248–308
     No AIDS off HAART 158 149–203
     AIDS off HAART 240 207–277
  Annual cost of HAART Regimens
  (2007USD)		 MSF58, Aidsmap31, Badri30
     3 NRTIs (based on AZT + 3TC +
     ABC)		 548
     2 NRTIs + NNRTI (based on
     AZT + 3TC + NVP or EFV)		 199
     2 NRTIs + PI/r (based on TDF +
     3TC + LPV/r)		 737
     2 NRTIs + 2nd gen PI/r (based on
     TDF + 3TC + DNV/r)		 1,332
  Cost of CD4 test (2007 USD) 15 10–25 Badri24, Zijenah59
  Cost of viral load test (2007 USD) 45 15–75 Rouet60, Calmy61