Number needed to screen for TB in clinical, structural or occupational risk groups

Area of Science:

• Public Health
• Epidemiology
• Infectious Disease Control

Background:

• Active case-finding (ACF) aims to reduce tuberculosis (TB) incidence, prevalence, and mortality.
• The effectiveness of ACF interventions, measured by yield, varies considerably across different populations.
• Systematic review to calculate the number needed to screen (NNS) for TB in high-risk adult groups.

Purpose of the Study:

• To systematically review studies on ACF for active TB in adults.
• To calculate the number needed to screen (NNS) for various high-risk groups.
• To stratify NNS by screening strategy, risk group, and country-level TB incidence.

Main Methods:

• Literature search for ACF studies in adults (November 2010 - February 2020).
• Included 90 studies, analyzing active TB prevalence detected by different screening strategies.
• Calculated crude and weighted mean NNS, stratified by risk group, screening strategy, and TB incidence.

Main Results:

• NNS varied widely across and within different TB incidence settings.
• High-risk groups included inpatients, outpatients, people living with diabetes, migrants, prison inmates, persons experiencing homelessness, healthcare workers, and miners.
• Screening tools with higher sensitivity, such as Xpert MTB/RIF and chest X-ray, were associated with lower NNS.

Conclusions:

• The number needed to screen (NNS) for active TB using ACF strategies differs substantially among adult risk groups.
• Screening interventions should be customized based on local TB epidemiology and cost-effectiveness.
• Tailoring ACF strategies can optimize resource allocation and improve TB control outcomes.