Comparative yield of different active TB case finding interventions in a large urban TB project in central Uganda: a descriptive study.

Andrew Kazibwe,Fred Twinomugisha,Debora B Freitas Lopez,Seyoum Dejene,Disan Lukanga,Abel Nkolo,Nicholas Sebuliba Kirirabwa,Florence Nakaggwa,Joseph Musaazi,Stella Zawedde-Muyanja,Timothy Kiyemba,Estella Birabwa,Phillip Aleu

doi:10.4314/ahs.v21i3.3

Abstract

Systematic screening for TB among patients presenting to care and among high risk populations is recommended to improve TB case finding. We aimed to describe the comparative yield of three TB screening approaches implemented by a large urban TB project in central Uganda. We abstracted data on the screening cascade from 65 health facilities and their surrounding communities (numbers screened, with presumptive TB, receiving a diagnostic test and diagnosed with TB) from the different clinic and community TB registers. From January 2018 to December 2019, 93,378 (24%) of all patients screened at health facilities had presumptive TB; 77,381 (82.9%) received a diagnostic test and 14,305 (18.5%) were diagnosed with TB. The screening yield (the number of patients diagnosed with TB out of all patients screened) was 0.3% and was three times higher among men than women (0.6% vs 0.2% p<0.01). During targeted community screening interventions, 9874 (21.1%) of all patients screened had presumptive TB; 7034 (71.2%) of these received a diagnostic test and 1699 (24.2%) were diagnosed with TB. The screening yield was higher among men, (3.7% vs 3.3% p<0.01) and highest among children 0-14 (4.8% vs 3.2% p<0.01). Targeted community TB screening interventions improve access to TB diagnosis for men and children 0-14 years.

Highlights

Systematic screening for TB among patients presenting to care and among high risk populations is recommended to improve TB case finding
We found that the TB screening yield from targeted community interventions, e.g., household contact tracing contributed significantly to TB case finding with high screening yields
We found that the TB screening yield was higher among men than women but that this ratio decreased as case finding interventions moved from the health facility to the community and to the household

Summary

Introduction

Systematic screening for TB among patients presenting to care and among high risk populations is recommended to improve TB case finding. The WHO defines systematic screening as the regular identification of people with suspected active TB, in predetermined target groups, using tests or procedures that can be applied rapidly Among those with active TB, diagnosis is made using diagnostic tests with high specificity[3,4]. In this context, systematic screening is predominantly provider-initiated and may target people in the community who have not yet sought healthcare services or people who have presented to public health facilities but do not have or do not recognize TB signs and symptoms. Compared to passive TB case-finding, which looks for TB among people actively seeking care due to symptoms compatible with TB5, systematic screening increases the number of patients initiated on TB treatment and results in earlier case-finding. Studies comparing delays to treatment initiation or extent of disease at presentation between those identified through systematic screening and those identified through passive case finding found that patients identified through systematic screening had shorter duration of symptoms[8,9], lower grades of smear positivity[8] and were less likely to have severe chest X-ray features such as cavitation[10]

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