Systematic screening for active TB operational manual and tool to help prioritization Wolfheze 2015 Knut Lönnroth, Global TB Programme, 1
Strong recommendations = Should be screened in all settings 1. Household contacts and other close contacts should be systematically screened for active TB. 2. People living with HIV should be systematically screened for active TB at each visit to a health facility. 3. Systematic screening for active TB should be done in current and former workers in workplaces with silica exposure 2
Conditional recommendations = prioritization needed 4. Systematic screening for active TB should be considered in prisons and other penitentiary institutions. (including staff) 5. Systematic screening for active TB should be considered in people with untreated fibrotic CXR lesion. 6. In settings where the TB prevalence is 100/100,000 in the general population, systematic screening for active TB should be considered among people who are seeking care or who are in care and belong to selected risk groups (see remarks, including staff) 3
Conditional recommendations, cont. 7. A. Systematic screening may be considered for geographically defined sub-populations with extremely high levels of undetected TB (>1% prevalence) B. Systematic screening may be considered also for other subpopulations with very poor health care access, such as urban slum dwellers, homeless people, people living remote areas with poor access, indigenous populations, migrants, and other vulnerable groups. 4
Operational guide
Planning & implementation cycle 1. Situation assessment / 6. Monitoring and evaluation 5. Planning, budgeting, implementation 2. (Re-)Define goals and specific objectives 4. Choose screening and diagnostic algorithms 3. (Re-) prioritization of risk-groups
Tool for prioritization of risk groups (slides from Cecily Miller, UCSF) Estimates the following for each risk group and each algorithm: Case-finding yield (true and false positive) Number needed to screen to detect one true case Total cost Cost per true case detected Allows for comparison of estimates Across risk groups Across screening algorithms
Step 1 Select the country User begins by selecting the country for exploration: Cambodia Country selection auto-populates data on: Total population size TB prevalence per 100,000 HIV prevalence Household size (when available)
Step 2 Select risk groups Contacts Miners PLHIV Diabetics
Step 3 Estimating risk group size Miners Contacts PLHIV Diabetics 2 ways to specify population size of selected risk groups: 1. Estimate size of risk group as % of country population (default) 2. Estimate absolute size of risk group
Step 4 Estimating TB prevalence in each risk group Miners Contacts PLHIV Diabetics 2 ways to specify TB prevalence within risk groups: 1. Enter or estimate relative risk of TB in risk group compared to general population (default) 2. Enter or estimate absolute TB prevalence per 100k
Step 5 Reachability & acceptability Miners Contacts PLHIV Diabetics Enter the % of the risk group expected to be reachable Enter the % of the risk group expected to accept screening Findings from acceptability systematic review pre-filled as suggested values
Algorithms (default, with changeable values for sensitivity and specificity) 1a. Cough screen Sputum smear microscopy 1b. Cough screen Xpert 1c. Cough screen CXR Sputum smear microscopy 1d. Cough screen CXR Xpert 2a. Any symptom screen Sputum smear microscopy 2b. Any symptom screen Xpert 2c. Any symptom screen CXR Sputum smear microscopy 2d. Any symptom screen CXR Xpert 3a. CXR Sputum smear microscopy 3b. CXR Xpert Note: - Clinical diagnosis / empirical treatment considered for persons negative on diagnostic test for all algorithms - Culture can be included, by replacing Xpert assumptions
Step 6 costs User estimates cost of per person screened: 1. Test cost 2. Operational cost
https://wpro.shinyapps.io/screen_tb/ Developed by Knut Lönnroth, Cecily Miller and Nobu Nishikiori Programmed in RStudio by Nobu Nishikiori
Total yield
Algorithm No. of true and false positive cases CXR Xpert Cough CXR Xpert Cough smear microscopy CXR Xpert Cough CXR Xpert Cough smear microscopy
Costs per true case, across algorithms:
Incremental cost-effectiveness
Tool considerations & limitations Focus on pulmonary TB (bacteriologically confirmable) The tool is exploratory, not for detailed planning purposes Tool estimates are based on several assumptions The uncertainty of each estimate compounds the uncertainty of the overall estimates Does not model the impact on transmission and TB incidence Does not estimate patient cost (only provider) Algorithm options developed mostly for low- and middleincome countries
Acknowledgements Cecily Miller Nobu Nishikiori Screening operational guide review committee Thank you