Tuberculosis contact tracing yield and associated factors in Uganda

Joseph Baruch Baluku,Martin Nabwana,Felix Bongomin,Muttamba Winters

doi:10.1186/s12890-022-01860-z

Joseph Baruch Baluku, Martin Nabwana + Show 2 more

Open Access

https://doi.org/10.1186/s12890-022-01860-z

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Abstract

BackgroundThe yield of tuberculosis (TB) contact tracing is historically low in Uganda. We determined factors associated with a positive contact tracing yield at an urban public TB clinic in Kampala, Uganda.MethodsWe reviewed contact tracing registers of index TB cases registered between 2015 and 2020 at Kitebi Health Center, a primary level facility. Contacts who had symptoms of TB were designated as having presumptive TB. A contact investigation that yielded a new TB case was designated as a positive yield. We used logistic regression to determine factors associated with a positive yield of contact tracing.ResultsOf 778 index TB cases, 455 (58.5%) had a contact investigation conducted. Index cases with a telephone contact in the unit TB register (adjusted odds ratio (aOR) 1.66, 95% CI 1.02–1.97, p = 0.036) were more likely to have a contact investigation conducted than those who did not. Of 1350 contacts, 105 (7.8%) had presumptive TB. Of these, 73 (69.5%) were further evaluated for active TB and 29 contacts had active TB. The contact tracing yield for active TB was therefore 2.1% (29/1,350). The odds of a positive yield increased tenfold with each additional presumptive contact evaluated for active TB (aOR 10.1, 95% CI 2.95–34.66, p < 0.001). Also, retreatment index TB cases were more likely to yield a positive contact (aOR 7.69 95% CI 2.08–25.00, p = 0.002) than to new cases.ConclusionTB contact tracing should aim to evaluate all contacts with presumptive TB and contacts of retreatment cases to maximise the yield of contact tracing.

Highlights

The global burden of tuberculosis (TB) is falling at a slow rate
Among the 778 index cases, Factors associated with having a contact investigation conducted Index cases were more likely to have a contact investigation if they had a telephone contact in the register
We found that the odds of a positive yield increased with the number of contacts with presumptive TB that were evaluated for active TB

Summary

Introduction

The global burden of tuberculosis (TB) is falling at a slow rate. There was a 9% decline in the TB incidence between 2015 and 2019 against a 20% target that is required to achieve the 2020 milestones of the End TB strategy [1]. An estimated 2.9 million people who developed TB in 2019 were not notified either because they did not receive a TB diagnosis or Contact tracing is the systematic evaluation of household and close social contacts of an index TB case to identify additional TB cases [5]. In addition to identifying additional TB cases, contact tracing is associated with treatment success among index TB cases [6, 7]. The World Health Organisation (WHO) recommends contact tracing among household and close contacts of an index TB case who has any of sputum-positive. The yield of tuberculosis (TB) contact tracing is historically low in Uganda. We determined factors associated with a positive contact tracing yield at an urban public TB clinic in Kampala, Uganda

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