title: Follow-up of chronic coughers improves tuberculosis case finding: results from a community-based cohort study in southern Ethiopia.
abstract: BACKGROUND
  Untreated smear-positive tuberculosis (TB) patients are the primary source of infection; however, a large number of TB cases have not been identified and are untreated in many sub-Saharan African countries, including Ethiopia. This study determined whether or not a community-based follow-up of chronic coughers improves detection of TB cases and the risk factors for death among such cases.
  
  
  METHODS
  We conducted a census in six rural communities in Sidama, southern Ethiopia. Based on interview and sputum investigation, we identified 724 TB smear-negative chronic coughers, and did a cohort study of these chronic coughers and 1448 neighbourhood controls. For both chronic coughers and neighbourhood controls, we conducted a TB screening interview and performed sputum microscopy, as required, at 4, 7 and 10 months. Between September 2011 and June 2012, we followed chronic coughers and neighbourhood controls for 588 and 1,204 person-years of observation, respectively.
  
  
  RESULTS
  Of the chronic coughers, 23 developed smear-positive TB (incidence rate = 3912/105 person-years) compared to three neighbourhood controls who developed smear-positive TB (incidence rate = 249/105 person-years). The male-to-female ratio of smear-positive TB was 1:1. We demonstrated that chronic coughers (adjusted hazards ratio [aHR], 13.5; 95% CI, 4.0-45.7) and the poor (aHR, 2.6; 95% CI, 1.1-5.8) were at high-risk for smear-positive TB. Among the study cohort, 15 chronic coughers and two neighbourhood controls died (aHR, 14.0; 95% CI, 3.2-62.4).
  
  
  CONCLUSIONS
  A community-based follow-up of chronic coughers is helpful in improving smear-positive TB case detection, it benefits socioeconomically disadvantaged people in particular; in rural settings, chronic coughers had a higher risk of death.
authors.affiliation: Centre for International Health, University of Bergen, Bergen, Norway; School of Public and Environmental Health, Hawassa University, Hawassa, Ethiopia.
authors.forename: Endrias M
authors.initials: EM
authors.lastname: Woldesemayat
authors.affiliation: Liverpool School of Tropical Medicine, Liverpool, United Kingdom; TB REACH Project, Hawassa, Ethiopia.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Datiko
authors.affiliation: School of Public and Environmental Health, Hawassa University, Hawassa, Ethiopia.
authors.forename: Bernt
authors.initials: B
authors.lastname: Lindtjørn
mesh_terms: D000328:Adult; D002908:Chronic Disease / Q000453:epidemiology; D015331:Cohort Studies; D003371:Cough / Q000453:epidemiology* / Q000473:pathology; D003695:Delivery of Health Care; D005002:Ethiopia; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012424:Rural Population / Q000706:statistics & numerical data; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000453:epidemiology* / Q000473:pathology