Measuring TB incidence, prevalence and mortality: an overview of the recommendations of the WHO Global Task Force on TB Impact Measurement

Transcription

1 Measuring TB incidence, prevalence and mortality: an overview of the recommendations of the WHO Global Task Force on TB Impact Measurement Ana Bierrenbach WHO /STB / TME bierrenbacha@who.int Task Force web page

2 What are the global targets? 1. Outcome targets, DOTS (WHA*, Stop TB Partnership) Detect 70% of new sputum smearpositive (SS+) cases Successfully treat 85% of detected new SS+ cases 2. Impact targets (MDGs, Stop TB Partnership) Halt and reverse incidence by 2015 (MDG 6) Halve cases and deaths by 2015 vs baseline * World Health Assembly

3 Why is it important to measure TB impact? Scale up of financial investments TB Greater demand for health information Evidence based public health policy Accountability (Effectiveness and costeffectiveness of public health interventions)

4 The WHO Global Task Force on TB Impact Measurement 1. Mandate Produce robust, rigorous, widelyendorsed assessment of whether the 2015 impact targets are achieved Regularly report on progress towards impact targets in years leading up to 2015 Strengthen national capacity in monitoring and evaluation 2. Strategic approach three branched* Strengthened national surveillance "certification"/"validation" of notification data Development of vital registration systems Periodic updating of methods for producing estimates from surveillance and survey data Prevalence surveys in 21 global focus countries 3. Membership *See WHO Policy Paper to be published early 2009

5 Framework for assessment of TB surveillance data TB notification data Are data reliable and complete? Do notifications reflect trends in incidence? Does VR data reflect changes in TB mortality High coverage with no missing reports No duplications, no misclassifications Data internally and externally consistent Vital registration (VR) data Accurate and with high coverage Timechanges in notifications of cases and deaths Changes in casefinding, case definitions, ICD codes, coverage of surveillance systems, TB determinants IMPROVE surveillance system Evaluate trends and impact of TB control Do notifications include all incident cases? Does the VR system include all TB deaths? Apply "onion" model to identify where cases may be missing Inventory studies with existing or newly developed study registries Capture recapture studies notifications incidence VR mortality data deaths UPDATE estimates of TB incidence and mortality If appropriate, CERTIFY TB surveillance data as a direct measure of TB incidence and mortality

6 Strengthening surveillance (current status and road map) 1. Strengthening surveillance via: Increasing country capacity in the analysis of surveillance data using an innovative, systematic approach Making better use of available data Regional workshops and country missions 2. Certification/validation of surveillance data Surveillance data certified/validated as direct proxy of incidence for first wave of countries by 2010 or revised estimates of incidence Most countries to have implemented certification/validation process by 2015

7 The 21 global focus countries for TB disease prevalence surveys Asian countries on track, African countries not

8 Criteria used to identify 21 global focus countries Groups Estimated Prevalence SS+ TB (per 100,000 pop) Share of global burden SS+ TB Estimate HIV prevalence adults Baselines survey already done % % 1% % 4 yes

9 Methods to produce estimates (current status and road map) Strategy to review of existing methods Improving estimation of TB incidence and trends via systematic assessment of surveillance and programmatic data Systematic documentation of expert opinion Literature review of many assumptions New data for MDRTB and HIV prevalence among TB patients Simplification of models Global Burden of Disease Study

10 Key messages 1. Robust recording and reporting systems at national and global level 2. Strong basis for strengthening of surveillance and analysis of surveillance data at national level 3. Need for robust and widelyendorsed estimates of incidence, prevalence and mortality for measurement of impact of TB control 4. Comprehensive WHO Policy Package to measure impact by 2015 exists and needs to be implemented right away

11 Where to find more information about the Task Force recommendations Lancet review article published on methods for measuring TB incidence, prevalence and mortality (Jan '08) Policy paper building on Lancet review (Sep 08, finalized '09) Web site (Sep '09) ment_taskforce/en/index.html