Cost effectiveness of rapid HIV and syphilis testing algorithms in antenatal care Claire C. Bristow,...
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Transcript of Cost effectiveness of rapid HIV and syphilis testing algorithms in antenatal care Claire C. Bristow,...
Cost effectiveness of rapid HIV and syphilis testing algorithms in antenatal care
Claire C. Bristow, MScFielding School of Public Health
University of California, Los Angeles
Satellite Session Sunday July 20th, 2014
Dualelimination.org
What is a cost-effectiveness study?
• Economic analysis that compares relative costs and outcomes – In this case we’re looking rapid point-of-care HIV
and syphilis testing algorithms
Why do we do cost-effectiveness studies?
• The concept of cost effectiveness is applied to resource allocation and management activities
– Getting the most “bang for your buck” – Spending the least to gain the most– Using evidence to determine how to prioritize
resources: “evidence-based public health”
Goals
1. To measure adverse pregnancy outcomes associated with alternative testing strategies
2. To measure the monetary costs of alternative testing strategies
3. To develop a cost-effectiveness model for policy-makers and implementers to determine the most cost-effective dual elimination strategy
• We used Malawi as the base case for this analysis
• Option B+ start lifelong highly-active antiretroviral therapy at 14 weeks of gestation
5 Testing Algorithms
Dual rapid test for HIV and syphilis
• 1 single rapid test for HIV• 1 single rapid test for syphilis
• HIV rapid test • Lab-based TPPA/RPR for syphilis
HIV rapid test only
No Testing
Simulation Model• 100,000 pregnant women in
Malawi• Followed through decision tree
(testing pathway) and treatment, each step governed by probabilities
• Key inputs from data out of Malawi
• TreeAge Pro Software (Williamstown MA, USA)
Simulation Model
• Estimated expected adverse pregnancy outcomes based on each testing strategy– HIV mother-to-child transmission (MTCT)– Newborn syphilis infection– Prematurity/low birth weight– Neonatal death– Stillbirth
Decision Tree – Simulation model
• A schematic tree-shaped diagram used to show a statistical probability
• Each branch of the decision tree represents a possible event
• The tree structure shows how one choice or event leads to the next, and the use of branches indicates that each option is mutually exclusive
Decision tree - No testing
No testing
Proportion HIV uninfected
Proportion of HIV uninfected women
who are syphilis uninfected
Proportion of these women with adverse pregnancy outcome
Proportion of HIV uninfected women
who are syphilis infected
Proportion of these women with adverse pregnancy outcome
Proportion HIV infected
Proportion of HIV infected women who
are syphilis uninfected
Proportion of these women with adverse pregnancy outcome
Proportion of HIV infected women who are syphilis infected
Proportion of these women with adverse pregnancy outcome
.106
.9891
.0109.894
.978
.022
One branch of the HIV rapid test only decision tree
HIV rapid test algorithm
Proportion of women receiving
HIV rapid test
HIV infected
HIV test positive (test sensitivity)
HIV treatment received
Syphilis infected Pregnancy outcome
Syphilis uninfected
Pregnancy outcome
HIV treatment LTFU …
HIV test negative …
HIV uninfected …
Not tested …
COST EFFECTIVENESS ANALYSIS
Costs• We considered costs of testing incurred by
both the health system and the woman (labor costs determined using standard WHO health worker salaries for the region, patient travel costs, and test costs, etc.)
• We included costs of treatment for both syphilis and HIV infection in the pregnant woman and infant
• All costs were converted to 2012 US Dollars.
Effectiveness: Disability adjusted life years (DALYs)
• The disability adjusted life years (DALYs) is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death
• DALYs were calculated using disability weights from the Global Burden of Disease study1
• A disability weight is a weight factor that reflects the severity of the disease on a scale from 0 (perfect health) to 1 (equivalent to death)
• DALYs were adjusted for co-infection2
1. Lopez et al 20062. Owusu-Edusei et al 2014
DALYs• The DALY metric is used to provide a single number
to capture the health impact caused by a illness
• A DALY of 1 could represent 1 year of life lost (due to early death), 1.7 years spent with blindness, 5.2 episodes of malaria, etc.
• Syphilis infection in the infant has a disability weight of 0.315 per year and is estimated to last for 3 years. So a child born with congenital syphilis would receive a lifetime DALY value of 0.945
Incremental cost effectiveness ratio
• Cost-effectiveness is typically expressed as an incremental cost effectiveness ratio (ICER), the ratio of change in costs to the change in effects
ICER =
Key inputs: epidemiology
Cohort• 10.6% HIV prevalence among pregnant
women1 – 24.8% of those with AIDS2
• 1.09% syphilis prevalence among HIV-uninfected1
• 2.2% syphilis prevalence among HIV-infected1
1. Malawi Government 20122. Mwapasa 2006
Key inputs
Test accuracy • Sensitivity and specificity estimates were
determined from literature review of field studies
Key inputs: Health system structure and use
Treatment • Option B+ for treatment of HIV infection• Treatment for maternal syphilis infection with
one injection (2.4 MU Benzathine Penicillin)
Key inputs: Costs
Screening test costs• $0.80 Single HIV rapid test• $0.55 Single Syphilis rapid test• $2.39 Syphilis laboratory tests (RPR/TPPA)1
• $1.30 Dual Rapid test – SD Duo®
Patient costs• Treatment costs for syphilis or HIV infection for life
of infant • Pregnancy outcome costs1. Owusu-Edusei 2011
RESULTS
Expected adverse pregnancy outcomes per 100,000 pregnancies
No testing program 17,127 adverse outcomes
HIV rapid testing only 15,820 adverse outcomes
HIV rapid testing and laboratory-based syphilis testing
15,779 adverse outcomes
1 single HIV and 1 single syphilis rapid testing
15,775 adverse outcomes
Dual HIV/syphilis testing 15,370 adverse outcomes
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
186 186 174 173 51
4852 4852 4836 4834 4669
3112 3112 3105 3104 3031
6370 6370 6365 6365 6319
2607 1300 1299 1299 1300 HIV MTCT
Prematurity/ Low Birth Weight
Neonatal Death
Still Birth or Fetal Loss
Syphilis Infec-tion in Infant
Num
ber
of A
dver
se P
regn
ancy
Out
com
es
Summary results from the cohort decision model comparing the expected effects (DALYs) of the pregnancy and costs (2012 U.S. Dollars) for all 5 antenatal HIV and syphilis testing algorithms and a no-testing strategy in the Malawi setting.
Total Program and Outcome
Costs
No testing$20,783,454
Dual HIV/syphilis$21,274,678
HIV test only$21,583,611
Single rapid tests for HIV & syphilis $21,593,145
HIV rapid test & RPR/TPPA for syphilis $21,605,356
Summary results from the cohort decision model comparing the expected effects (DALYs) of the pregnancy and costs (2012 U.S. Dollars) for all 5 antenatal HIV and syphilis testing algorithms and a no-testing strategy in the Malawi setting.
Total Program and
Outcome Costs
DALYs
No testing$20,783,454 269,400
Dual HIV/syphilis$21,274,678 228,829
HIV test only$21,583,611 235,716
Single rapid tests for HIV & syphilis $21,593,145 235,023
HIV rapid test & RPR/TPPA for syphilis $21,605,356 235,094
Summary results from the cohort decision model comparing the expected effects (DALYs) of the pregnancy and costs (2012 U.S. Dollars) for all 5 antenatal HIV and syphilis testing algorithms and a no-testing strategy in the Malawi setting.
Total Program and
Outcome Costs
Cost increase from no testing
DALYS
No testing$20,783,454
-269,400
Dual HIV/syphilis$21,274,678 $491,224 228,829
HIV test only$21,583,611 $800,158 235,716
Single rapid tests for HIV & syphilis $21,593,145 $809,692 235,023
HIV rapid test & RPR/TPPA for syphilis $21,605,356 $821,902 235,094
Summary results from the cohort decision model comparing the expected effects (DALYs) of the pregnancy and costs (2012 U.S. Dollars) for all 5 antenatal HIV and syphilis testing algorithms and a no-testing strategy in the Malawi setting.
Total Program and outcome
Costs
Cost increase from no testing
DALYS DALYs prevented compared
to no testing
No testing$20,783,454
-269,400 -
Dual HIV/syphilis$21,274,678 $491,224 228,829 40,571
HIV test only $21,583,611 $800,158 235,716 33,684
Single rapid tests for HIV & syphilis $21,593,145 $809,692 235,023 34,377
HIV rapid test & RPR/TPPA for syphilis $21,605,356 $821,902 235,094 34,306
Summary results from the cohort decision model comparing the expected effects (DALYs) of the pregnancy and costs (2012 U.S. Dollars) for all 5 antenatal HIV and syphilis testing algorithms and a no-testing strategy in the Malawi setting.
Total Program and outcome
Costs
Cost increase from no testing
DALYS DALYs prevented compared
to no testing
ICER*
No testing $20,783,454 - 269,400 - -
Dual HIV/syphilis $21,274,678 $491,224 228,829 40,571 12.11HIV test only $21,583,611 $800,158 235,716 33,684 Strictly
dominatedSingle rapid tests for
HIV & syphilis $21,593,145 $809,692 235,023 34,377Strictly
dominated
HIV rapid test & RPR/TPPA for syphilis $21,605,356 $821,902 235,094 34,306
Strictly dominated
*Incremental cost effectiveness ratio (ICER) is the ratio of the change in costs to incremental benefit of an algorithm.
Conclusions
• A dual HIV/syphilis testing algorithm in antenatal care would be the most effective means to reduce the number of adverse outcomes of pregnancy
• The dual point-of-care testing algorithm had lower overall costs and decreased life-time disability when compared to the other testing choices
Limitations
• Did not include procurement costs for tests or training costs
• Inputs are based on estimates from a variety of studies, actual measures may change over time
• This is a purely economic perspective, this doesn’t include the intangible values society places on pregnancy outcomes
Conclusions
• Integrating the screening of syphilis into antenatal HIV prevention programs through dual rapid point-of-care testing would increase the number of maternal infections detected and have the greatest impact on the prevention of HIV and syphilis related adverse pregnancy outcomes
Next steps, sensitivity analyses
Visit our posters!
• "Cost-effectiveness of dual HIV and syphilis testing“ - Thursday, 24 July 2014 from 12:30 - 14:30, Exhibition Hall, Ground Level THPE416
• “Field evaluation of a dual rapid diagnostic test for HIV and syphilis in Lima Peru using SD BIOLINE HIV/Syphilis Duo“ - Wednesday, 23 July 2014 from 12:30 - 14:30, Exhibition Hall, Ground Level WEPE050
Acknowledgements
• Jeffrey Klausner, UCLA• Elysia Larson, Harvard
• Thomas Gift, CDC• Kwame Owusu-Edusei, CDC• Lori Newman, WHO• Fern Terris-Prestholt, LSHTM• Peter Vickerman, Bristol University
THANK YOU
Please get in touch if you want more information or have comments.
Dualelimination.org