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Table 3 Model parameters

From: Cost effectiveness of option B plus for prevention of mother-to-child transmission of HIV in resource-limited countries: evidence from Kumasi, Ghana

Variable Value Range Source
Demographic variables    
Annual maternal mortality rates    UNICEF [20]
<12 months ART    
>350 cells/mm3 3.3% -  
200-350 cells/mm3 3.9% -  
<200 cells/mm3 11.1% -  
>12 months ART    
>350 cells/mm3 1.0% -  
200-350 cells/mm3 1.1% -  
<200 cells/mm3 1.8% -  
Number of children 2.34 1-5 Chart review
Transition Probabilities    
Access to care 82% 50-95% Ghana Health Service [7]
Adherence to ART 90% 50-95% Ghana Health Service [7]
Transmission during pregnancy    
No therapy/non-adherence 22% 15-30% Ghana Health Service [12]
Option B 10%Ϯ 0-15% Ghana Health Service [12]
Option B-Plus 1% 0-5% Ghana Health Service [12]
Transmission during breastfeeding    
No therapy/non-adherence 10% 5-20% Ghana Health Service [12]
Option B 1% 0-5% Ghana Health Service [12]
Option B+ 1% 0-5% Ghana Health Service [12]
Changes to CD4 Count    
No therapy (every 3 months) −12.75 cells/mm3 5-20 cells/mm3 Holmes 2006 [15]
Initiate therapy +153 cells/mm3 100-400 cells/mm3 Deeks 1999 [16]
Continue therapy (every 3 months)    
Previously interrupted therapy −0.06365 × [Current CD4] - Ickovics et al. 2001 [14]
Continuous therapy - 0.0099853 × [Current CD4] - Ickovics et al. 2001 [14]
Costs in USD [GHS]    
Annual Cost of HIV Care    
First-Line ART 385.45 [743.91] 191-580 WHO 2011 [17]; Rosen, J., and F. Asante. 2010 [18]
Second-Line ART 848.33 [1,637.28] - WHO 2011 [17]; Rosen, J., and F. Asante. 2010 [18]
Lifetime Cost of Care for HIV+ Child (including ART costs) 10,665.49 [20,584.40] 5,181-15,544 WHO 2011 [17]; Rosen, J., and F. Asante. 2010 [18]
Quality-of-life Factor    
HIV+ adult (quality of life) 0.8 0.50-1.0 Tengs T.O., Lin T.H. 2002 [19]
HIV+ child (lifetime QALYs) 20.2ϮϮ 10-30 UN Impact of AIDS 2004 [32]
HIV- child (lifetime QALYs) 62.7 50-70 UN Impact of AIDS 2004 [32]
Discount rate 0.03 0.00-0.05 Weinstein et al. 1996 [23]
  1. ϮProbability of transmission during pregnancy/delivery while on Option B was determined by applying the distribution of when women accessed antenatal care (found through chart review) with ideal conditions of Option B (beginning therapy at the beginning of the second trimester) indicated by the Ghana Health Service and WHO.
  2. ϮϮLifetime QALYs for an HIV-positive child assume a life expectancy at birth of 47.1 years [32] with a yearly utility of 0.82 and a discount rate of 0.03.
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