How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia

Objective Many individuals with persistent cough and smear microscopy-negative sputum test for tuberculosis (TB) remain at risk of developing the disease. This study estimates the incidence of pulmonary TB (PTB) among initially smear-negative persistent coughers and its risk factors.Design A prospec...

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Main Authors: Brita Askeland Winje, Richard Aubrey White, Einar Heldal, Sven Gudmund Hinderaker, Abiot Bezabeh Banti, Daniel Gemechu Datiko, Mesay Hailu Dangisso, Gebeyehu Assefa Mitiku
Format: Article
Language:English
Published: BMJ Publishing Group 2022-05-01
Series:BMJ Open
Online Access:https://bmjopen.bmj.com/content/12/5/e058466.full
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author Brita Askeland Winje
Richard Aubrey White
Einar Heldal
Sven Gudmund Hinderaker
Abiot Bezabeh Banti
Daniel Gemechu Datiko
Mesay Hailu Dangisso
Gebeyehu Assefa Mitiku
author_facet Brita Askeland Winje
Richard Aubrey White
Einar Heldal
Sven Gudmund Hinderaker
Abiot Bezabeh Banti
Daniel Gemechu Datiko
Mesay Hailu Dangisso
Gebeyehu Assefa Mitiku
author_sort Brita Askeland Winje
collection DOAJ
description Objective Many individuals with persistent cough and smear microscopy-negative sputum test for tuberculosis (TB) remain at risk of developing the disease. This study estimates the incidence of pulmonary TB (PTB) among initially smear-negative persistent coughers and its risk factors.Design A prospective population-based follow-up study.Setting Health extension workers visited all households in Dale woreda three times at 4-month intervals in 2016–2017 to identify individuals with symptoms compatible with TB (presumptive TB) using pretested and semistructured questionnaires.Participants We followed 3484 presumptive TB cases (≥15 years) with an initial smear-negative TB (PTB) test.Outcome measures Bacteriologically confirmed PTB (PTB b+) and clinically diagnosed PTB (PTB c+).Results 3484 persons with initially smear-negative presumptive PTB were followed for 2155 person-years (median 0.8 years); 90 individuals had PTB b+ and 90 had PTB c+. The incidence rates for PTB b+ and PTB c+ were both 4176 (95% CI 3378 to 5109) per 100 000 person-years. We used penalised (lasso) and non-penalised proportional hazards Cox regression models containing all exposures and outcomes to explore associations between exposures and outcomes. In lasso regression, the risk of development of PTB b+ was 63% (HR 0.37) lower for people aged 35–64 years and 77% (HR 0.23) lower for those aged ≥65 years compared with 15–34 year-olds. Men had a 62% (HR 1.62) greater risk of PTB b+ development than women. The risk of PTB c+ was 39% (HR 0.61) lower for people aged 35–54 years than for those aged 15–34 years. Men had a 56% (HR 1.56) greater risk of PTB c+ development than women.Conclusions PTB incidence rate among persistent coughers was high, especially among men and young adults, the latter signifying sustained transmission. Awareness about this among healthcare workers may improve identification of more new TB cases.
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spelling doaj-art-a0fa5a7d5dab4e5684be18adf7a34dd72025-08-20T01:47:47ZengBMJ Publishing GroupBMJ Open2044-60552022-05-0112510.1136/bmjopen-2021-058466How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in EthiopiaBrita Askeland Winje0Richard Aubrey White1Einar Heldal2Sven Gudmund Hinderaker3Abiot Bezabeh Banti4Daniel Gemechu Datiko5Mesay Hailu Dangisso6Gebeyehu Assefa Mitiku74 Department of Infection Control and Vaccine, Norwegian Institute of Public Health, Oslo, Norway7 Department of Methods Development and Analytics, Norwegian Institute of Public Health, Oslo, NorwayDepartment of Infection Control and Vaccines, Norwegian Institute of Public Health, Oslo, NorwayCentre for International Health, University of Bergen, Bergen, NorwayREACH Ethiopia, Addis Ababa, Ethiopia2 Management Sciences for Health Ethiopia, Addis Ababa, EthiopiaEthiopian Public Health Institute, Addis Ababa, Ethiopia6 Armauer Hansen Research Institute, Addis Ababa, EthiopiaObjective Many individuals with persistent cough and smear microscopy-negative sputum test for tuberculosis (TB) remain at risk of developing the disease. This study estimates the incidence of pulmonary TB (PTB) among initially smear-negative persistent coughers and its risk factors.Design A prospective population-based follow-up study.Setting Health extension workers visited all households in Dale woreda three times at 4-month intervals in 2016–2017 to identify individuals with symptoms compatible with TB (presumptive TB) using pretested and semistructured questionnaires.Participants We followed 3484 presumptive TB cases (≥15 years) with an initial smear-negative TB (PTB) test.Outcome measures Bacteriologically confirmed PTB (PTB b+) and clinically diagnosed PTB (PTB c+).Results 3484 persons with initially smear-negative presumptive PTB were followed for 2155 person-years (median 0.8 years); 90 individuals had PTB b+ and 90 had PTB c+. The incidence rates for PTB b+ and PTB c+ were both 4176 (95% CI 3378 to 5109) per 100 000 person-years. We used penalised (lasso) and non-penalised proportional hazards Cox regression models containing all exposures and outcomes to explore associations between exposures and outcomes. In lasso regression, the risk of development of PTB b+ was 63% (HR 0.37) lower for people aged 35–64 years and 77% (HR 0.23) lower for those aged ≥65 years compared with 15–34 year-olds. Men had a 62% (HR 1.62) greater risk of PTB b+ development than women. The risk of PTB c+ was 39% (HR 0.61) lower for people aged 35–54 years than for those aged 15–34 years. Men had a 56% (HR 1.56) greater risk of PTB c+ development than women.Conclusions PTB incidence rate among persistent coughers was high, especially among men and young adults, the latter signifying sustained transmission. Awareness about this among healthcare workers may improve identification of more new TB cases.https://bmjopen.bmj.com/content/12/5/e058466.full
spellingShingle Brita Askeland Winje
Richard Aubrey White
Einar Heldal
Sven Gudmund Hinderaker
Abiot Bezabeh Banti
Daniel Gemechu Datiko
Mesay Hailu Dangisso
Gebeyehu Assefa Mitiku
How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
BMJ Open
title How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
title_full How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
title_fullStr How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
title_full_unstemmed How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
title_short How many of persistent coughers have pulmonary tuberculosis? Population-based cohort study in Ethiopia
title_sort how many of persistent coughers have pulmonary tuberculosis population based cohort study in ethiopia
url https://bmjopen.bmj.com/content/12/5/e058466.full
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