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GHME 2013 Conference Session: Verbal Autopsy Date: June 18 2013 Presenter: Andrea Stewart Institute: Institute for Health Metrics and Evaluation (IHME), University of Washington
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Assessing verbal autopsy as a complement to vital registrationA data-driven simulation study
Andrea Stewart, Post-Bachelor FellowJune 18, 2013
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Presentation outline
• Uses of verbal autopsy (VA)
• Potential uses of new VA methods
• Creation of a simulation of incomplete vital registration (VR) complemented with VA estimates
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Presentation outline
• Uses of verbal autopsy (VA)
• Potential uses of new VA methods
• Creation of a simulation of incomplete vital registration (VR) complemented with VA estimates
4
Uses of verbal autopsy
Photo by Peter Biro/The IRC. ©2011 International Rescue Committee.
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Presentation outline
• Uses of Verbal Autopsy (VA)
• Potential uses of new VA methods
• Creation of a simulation of incomplete vital registration (VR) complemented with VA estimates
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Advancements in VA science
• Automated methods for collection and analysis
• Less time
• Fewer resources
• More accurate
Could we use VA in routine national data
collection?
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Presentation outline
• Uses of Verbal Autopsy (VA)
• Potential uses of new VA methods
• Creation of a simulation of incomplete vital registration (VR) complemented with VA estimates
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Simulation setting – the data
• Need data that has:
o VR estimates (death certificates)
o VA estimates (analyzed by Tariff)
o Known cause of death (based on stringent diagnostic criteria)
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Population Health Metrics Research Consortium gold standards
VA Tariff method results
Death certificate
Gold standard diagnosis
1,288 VAs from Morelos, Mexico
x 500 test data sets of varying cause composition
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Metrics
• Cause-specific mortality fractions (CSMFs)
• Measure of accuracy
• Change in that metric across situations
% Accuracy change=( 𝐴𝑐𝑐 h𝑤𝑖𝑡 𝑉𝐴−𝐴𝑐𝑐 𝑖𝑛𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒
𝐴𝑐𝑐𝑖𝑛𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒)×100%
𝐶𝑆𝑀𝐹𝐴𝑐𝑐𝑢𝑟𝑎𝑐𝑦=1−∑𝑗=1
𝑘
¿𝐶𝑆𝑀𝐹 𝑗𝑡𝑟𝑢𝑒−𝐶𝑆𝑀𝐹 𝑗
𝑝𝑟𝑒𝑑∨¿
2(1−𝑀𝑖𝑛𝑖𝑚𝑢𝑚(𝐶𝑆𝑀𝐹 𝑗𝑡𝑟𝑢𝑒))
¿
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Data – mortality registries from Morelos
• Mortality registries provide the proportion of deaths by age, sex, and cause of death that occur in health facilities
• %
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Simulation setting – the data
Using Morelos probabilities -
Deaths in facility Deaths out of facility
622 observations with: Death certificateVerbal autopsy
Gold-standard diagnosis
666 observations with: Death certificateVerbal autopsy
Gold-standard diagnosis
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Simulation setting – incomplete vital registration
Deaths in facility Deaths out of facility
Use death certificate data for
60%
Use death certificate data for 10%
No death certificate
No death certificate
Deaths in facility Deaths out of facility
Gold-standard diagnosis
Gold-standard diagnosis
vs.
𝑜𝑢𝑡𝑝𝑢𝑡 : 𝐴𝑐𝑐𝑖𝑛𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒
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Simulation setting – add VA estimates
vs.
Deaths in facility Deaths out of facility
Use death certificate data for
60%
Use death certificate data for 10%
Use verbal autopsy data for remaining
90%Use verbal autopsy data for remaining
40%
Deaths in facility Deaths out of facility
Gold-standard diagnosis
Gold-standard diagnosis
𝑜𝑢𝑡𝑝𝑢𝑡 : 𝐴𝑐𝑐 h𝑤𝑖𝑡 𝑉𝐴
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Simulation setting
• Do this for each of the simulated scenarioso 0%-100% deaths with DC in facility
o 0%-100% deaths with DC out of facility
• Calculate change in CSMF accuracy for each scenario
Accuracy change=( 𝐴𝑐𝑐 h𝑤𝑖𝑡 𝑉𝐴− 𝐴𝑐𝑐𝑖𝑛𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒
𝐴𝑐𝑐𝑖𝑛𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒)×100
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ResultsPercent change in CSMF accuracy when adding VA
% of out-of-facility deaths with death certificates 0 10 20 30 40 50 60 70 80 90 100
% of in-facility deaths with
death certificates
0 27.5 24.3 20.1 17.4 14.5 11.4 10.4 8.9 7.2 6.010 29.1 24.7 21.7 18.0 15.4 12.3 9.6 9.0 7.9 5.7 5.320 26.3 21.8 19.1 15.9 13.7 10.9 8.4 7.8 6.8 5.1 4.330 23.1 19.5 16.6 13.8 11.8 9.5 6.9 6.1 5.3 3.8 3.640 20.2 17.1 14.3 11.7 9.8 7.5 5.2 4.7 4.0 2.6 2.350 17.5 14.9 12.4 10.0 8.0 6.0 4.1 3.9 2.9 1.9 1.760 15.5 12.7 10.3 7.9 6.7 5.0 3.3 3.1 2.3 1.0 0.870 13.3 10.5 8.3 6.2 4.9 3.4 2.1 2.0 1.3 0.6 0.380 11.2 8.8 7.4 5.1 4.0 2.6 1.2 1.2 0.8 -0.1 0.290 9.6 7.9 6.2 3.9 2.7 1.8 0.6 0.6 0.2 -0.2 -0.1
100 8.5 7.0 5.3 3.2 2.2 0.8 0.3 0.2 0.3 -0.2 0.0
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ResultsPercent change in CSMF accuracy when adding VA
% of out-of-facility deaths with death certificates 0 10 20 30 40 50 60 70 80 90 100
% of in-facility deaths with
death certificates
0 27.5 24.3 20.1 17.4 14.5 11.4 10.4 8.9 7.2 6.010 29.1 24.7 21.7 18.0 15.4 12.3 9.6 9.0 7.9 5.7 5.320 26.3 21.8 19.1 15.9 13.7 10.9 8.4 7.8 6.8 5.1 4.330 23.1 19.5 16.6 13.8 11.8 9.5 6.9 6.1 5.3 3.8 3.640 20.2 17.1 14.3 11.7 9.8 7.5 5.2 4.7 4.0 2.6 2.350 17.5 14.9 12.4 10.0 8.0 6.0 4.1 3.9 2.9 1.9 1.760 15.5 12.7 10.3 7.9 6.7 5.0 3.3 3.1 2.3 1.0 0.870 13.3 10.5 8.3 6.2 4.9 3.4 2.1 2.0 1.3 0.6 0.380 11.2 8.8 7.4 5.1 4.0 2.6 1.2 1.2 0.8 -0.1 0.290 9.6 7.9 6.2 3.9 2.7 1.8 0.6 0.6 0.2 -0.2 -0.1
100 8.5 7.0 5.3 3.2 2.2 0.8 0.3 0.2 0.3 -0.2 0.0
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ResultsPercent change in CSMF accuracy when adding VA
% of out-of-facility deaths with death certificates 0 10 20 30 40 50 60 70 80 90 100
% of in-facility deaths with
death certificates
0 27.5 24.3 20.1 17.4 14.5 11.4 10.4 8.9 7.2 6.010 29.1 24.7 21.7 18.0 15.4 12.3 9.6 9.0 7.9 5.7 5.320 26.3 21.8 19.1 15.9 13.7 10.9 8.4 7.8 6.8 5.1 4.330 23.1 19.5 16.6 13.8 11.8 9.5 6.9 6.1 5.3 3.8 3.640 20.2 17.1 14.3 11.7 9.8 7.5 5.2 4.7 4.0 2.6 2.350 17.5 14.9 12.4 10.0 8.0 6.0 4.1 3.9 2.9 1.9 1.760 15.5 12.7 10.3 7.9 6.7 5.0 3.3 3.1 2.3 1.0 0.870 13.3 10.5 8.3 6.2 4.9 3.4 2.1 2.0 1.3 0.6 0.380 11.2 8.8 7.4 5.1 4.0 2.6 1.2 1.2 0.8 -0.1 0.290 9.6 7.9 6.2 3.9 2.7 1.8 0.6 0.6 0.2 -0.2 -0.1
100 8.5 7.0 5.3 3.2 2.2 0.8 0.3 0.2 0.3 -0.2 0.0
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ResultsPercent change in CSMF accuracy when adding VA
% of out-of-facility deaths with death certificates 0 10 20 30 40 50 60 70 80 90 100
% of in-facility deaths with
death certificates
0 27.5 24.3 20.1 17.4 14.5 11.4 10.4 8.9 7.2 6.010 29.1 24.7 21.7 18.0 15.4 12.3 9.6 9.0 7.9 5.7 5.320 26.3 21.8 19.1 15.9 13.7 10.9 8.4 7.8 6.8 5.1 4.330 23.1 19.5 16.6 13.8 11.8 9.5 6.9 6.1 5.3 3.8 3.640 20.2 17.1 14.3 11.7 9.8 7.5 5.2 4.7 4.0 2.6 2.350 17.5 14.9 12.4 10.0 8.0 6.0 4.1 3.9 2.9 1.9 1.760 15.5 12.7 10.3 7.9 6.7 5.0 3.3 3.1 2.3 1.0 0.870 13.3 10.5 8.3 6.2 4.9 3.4 2.1 2.0 1.3 0.6 0.380 11.2 8.8 7.4 5.1 4.0 2.6 1.2 1.2 0.8 -0.1 0.290 9.6 7.9 6.2 3.9 2.7 1.8 0.6 0.6 0.2 -0.2 -0.1
100 8.5 7.0 5.3 3.2 2.2 0.8 0.3 0.2 0.3 -0.2 0.0
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ResultsPercent change in CSMF accuracy when adding VA
% of out-of-facility deaths with death certificates 0 10 20 30 40 50 60 70 80 90 100
% of in-facility deaths with
death certificates
0 27.5 24.3 20.1 17.4 14.5 11.4 10.4 8.9 7.2 6.010 29.1 24.7 21.7 18.0 15.4 12.3 9.6 9.0 7.9 5.7 5.320 26.3 21.8 19.1 15.9 13.7 10.9 8.4 7.8 6.8 5.1 4.330 23.1 19.5 16.6 13.8 11.8 9.5 6.9 6.1 5.3 3.8 3.640 20.2 17.1 14.3 11.7 9.8 7.5 5.2 4.7 4.0 2.6 2.350 17.5 14.9 12.4 10.0 8.0 6.0 4.1 3.9 2.9 1.9 1.760 15.5 12.7 10.3 7.9 6.7 5.0 3.3 3.1 2.3 1.0 0.870 13.3 10.5 8.3 6.2 4.9 3.4 2.1 2.0 1.3 0.6 0.380 11.2 8.8 7.4 5.1 4.0 2.6 1.2 1.2 0.8 -0.1 0.290 9.6 7.9 6.2 3.9 2.7 1.8 0.6 0.6 0.2 -0.2 -0.1
100 8.5 7.0 5.3 3.2 2.2 0.8 0.3 0.2 0.3 -0.2 0.0
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Conclusion
In this preliminary simulation environment, adding VA estimates to incomplete VR scenarios improved CSMF accuracy much of the time.
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Future directions
• Update simulation environment to better reflect specific VR coverage scenarios
• Re-analyze the VAs assigned to “out of facility,” dropping questions determined to be related to “health care experience”
