Virtual Implementation Evaluation of Tuberculosis diagnostics in Tanzania Ivor Langley, Liverpool School of Tropical Medicine 3rd sector OR and developing countries 27th March 2013, London School of Economics
Outline Background - TB diagnostic tools in Tanzania Method - Virtual implementation Results - Example output What next?
TB diagnostic tools in Tanzania New TB diagnostic tools in Tanzania have the potential to make a real difference to the lives of many, particularly those living in poverty e.g. Ziehl Neelsen Microscopy LED Fluorescence Microscopy / Same Day? GeneXpert MTB/RIF Point of Care? Sensitivity 35-75% Specificity 99-100% Turnaround 48hrs Cost per test $1.50 Time per test ~60mins Extra Investment nil Sensitivity 40-80% Specificity 99-100% Turnaround 24-48hrs Cost per test $1.50 Time per test ~55mins Extra Investment $1,250 Sensitivity 80-95% Specificity 98-99% Turnaround <12hrs Cost per test $10-$17 Time per test ~2hrs Extra Investment $9k-18k Sensitivity? Specificity? Turnaround <1hr Cost per test? Time per test? Extra Investment?
TB diagnostic tools in Tanzania today ZN microscopy being replaced by LED fluorescence Spot and Morning sputum samples ~11% of pulmonary TB suspects are smear +ve ~45,000 pulmonary TB cases per year (<100 MDR-TB) ~38% of TB cases are HIV positive ~46% of pulmonary TB cases are smear -ve 76% TB case detection (WHO, 2011)
TB diagnostic tools in Tanzania - future? Current and planned trials of GeneXpert in Tanzania: There remain many questions including those around sustainability and the diagnostic algorithm
Method Modelling to project impacts Available data on current diagnostics in Context A Impacts of new diagnostics in Context A Trial data on new diagnostics in Contexts B, C, Patients Health System Community
Virtual implementation - what is it? OPERATIONAL MODEL Patient & Health System Effects TRANSMISSION MODEL Community & Disease Transmission Impacts WITNESS simulation tool Berkeley Madonna
Virtual implementation - what is it? Output Time to start treatment Diagnostic default rate Incremental Costs Input OPERATIONAL MODEL Patient & Health System Effects TRANSMISSION MODEL Community & Disease Transmission Impacts Input TB Incidence rate Incremental DALY s averted Output Combining the outputs to calculate the Incremental Cost Effectiveness Ratio (ICER) Lin HH, Langley I, et al. (2011), A modelling framework to support the selection and implementation of new tuberculosis diagnostic tools. Int J Tuberc Lung Dis 15(8):996 1004, doi:10.5588/ijtld.11.0062
Virtual implementation - outputs Projecting Impacts Operational Modelling Transmission Modelling Patients Health System Community Number tested, smear +ve, smear -ve, retreatment, treated, cured, MDR-TB, failed Time to complete diagnosis and start treatment Number of visits to diagnostic facilities required Number of samples collected, microscopy tests, X-rays, Xpert tests, cartridges Number of staff of each skill type required Number of treatments required of each type Incremental costs TB incidence TB prevalence TB mortality DALY s averted Incremental Cost Effectiveness Ratio (ICER)
Virtual implementation - what is it?
Virtual implementation - what is it?
Results example output Impact on number of TB cases cured ZN Microscopy LED Fluorescence LED Same Day New TB Cures Xpert for Sm- HIV+ & Retreat Xpert for Sm- HIV+ Known & Retreat Xpert for HIV+ and retreat Retreat TB Cures MDR-TB Treatment Fail Xpert for HIV+ known and retreat Xpert full roll-out 0 10000 20000 30000 40000 50000 Number of patients with active pulmonary TB that are cured There s a great benefit, but is it sustainable?
Results example output Impact on number and type of TB treatments required ZN Microscopy LED Fluorescence LED Same Day Xpert for Sm- HIV+ & Retreat Xpert for Sm- HIV+ Known & Retreat Test+ve TB Test-ve TB MDR-TB Xpert for HIV+ and retreat Xpert for HIV+ known and retreat Xpert full roll-out 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 Annual number of TB treatments
Results - example output Impact on TB epidemiology Decline in TB incidence Decline in TB prevalence * 2.4% * 4.0% * 7.6% * 9.3% Decline in TB mortality * 5.8% * 6.8%
Incremental annual health system costs Results - example output Impact on the costs to the TB programme over time $4,500,000 $4,000,000 $3,500,000 $3,000,000 $2,500,000 $2,000,000 $1,500,000 MDR Drugs First Line Drugs Diagnostic Tests Maintenance Equipment $1,000,000 $500,000 $0 1 2 3 4 5 6 7 8 9 10 Year
Results - example output Impact on HIV prevalence Incremental increase in HIV prevalence
Cumulative person-years on ART Results - example output Impact on HIV prevalence and ART requirements over time 16000 14000 12000 10000 8000 6000 4000 2000 0 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
Results - example output Supporting sustainable policy decisions Is the new tool Cost Effective? e.g. ICER relative to a threshold What are the Benefits of the new tool? e.g. DALY s averted Is the new tool Sustainable? e.g. can the additional annual cost to health service be afforded
Incremental Cost Effectiveness Ratio (Cost Effective?) Results - example output - projecting incremental cost effectiveness and affordability $225 $175 25720 Xpert for Smknown HIV+ NOTE: The size of the circle and the number in the circle represent the benefits measured in DALY's averted per year of the new tool relative to LED fluorescence microscopy (Benefit) LED $125 $75 $25 Same Day LED Xpert for known HIV+ 32426 Xpert Sm- & HIV+ 46970 72098 Xpert All HIV+ Xpert for all suspects 161622 60445 -$500,000 LED $500,000 $1,500,000 $2,500,000 $3,500,000 $4,500,000 -$25 Additional Annual Cost to Health Service (Sustainable?)
Incremental Cost Effectiveness Ratio (Cost Effective?) Results - example output - sensitivity to Xpert MTB/RIF cartridge price $200 $150 25720 NOTE: The size of the circle and the number in the circle represent the benefits measured in DALY's averted per year of the new tool relative to LED fluorescence microscopy (Benefit) LED $100 $50 LED $0 60445 32426 Xpert for all suspects $5 test 46970 72098 Xpert for all suspects $10 test 161622 Xpert for all suspects $17 test -$500,000 $500,000 $1,500,000 $2,500,000 $3,500,000 $4,500,000 $5,500,000 $6,500,000 -$50 Additional Annual Cost to Health Service (Sustainable?)
What Next? Tanzania and beyond o o o o Guiding where and how to implement Xpert MTB/RIF Guiding which alternatives to Xpert to use in districts where Xpert rollout is unsustainable Being implemented as a tool to be used by the national TB programme Other programmes considering making use of approach i.e. Kenya, Ethiopia, DR Congo, Sudan, Malawi and Brazil Multi drug resistant Tuberculosis (MDR-TB) o o Developing models to assist in impact assessment of alternative tools for MDR-TB in Brazil and South Africa (PhD research) Feasibility of application in China (Student project) Applications of approach in other disease areas o o Blood transfusion services in Kenya and Zimbabwe (Student project) Neglected tropical disease (NTD s) diagnostics Langley I, Doulla B, et al (2012). Modelling the impacts of new diagnostic tools for tuberculosis in developing countries to enhance policy decisions. Health Care Manag Sci DOI 10.1007/s10729-012-9201-3
Acknowledgements USAID YaDiul Mukadi Tanzania NTLP Dr Saidi Egwaga Basra Doulla Raymond Shirima Dr Riziki Kisonga The Union (Treat-TB) I.D. Rusen Anne Detjen Liverpool School of Tropical Medicine Bertie Squire Kerry Millington Russell Dacombe Harvard School of Public Health Ted Cohen Megan Murray National Taiwan University Hsien-Ho Lin Lanner Group Geoff Hook