title: Assessment of latent tuberculosis infection in psychiatric inpatients: A survey after tuberculosis outbreaks.
abstract: OBJECTIVE
  To investigate risk factors of latent tuberculosis infection (LTBI) among inpatients of chronic psychiatric wards with tuberculosis (TB) outbreaks.
  
  
  METHODS
  In April 2013, inpatients of four all-male wards with TB outbreaks were tested for LTBI using the QuantiFERON-TB Gold in Tube (QFT) method. Based on this investigation, a retrospective study was conducted to assess risk factors for LTBI. Inpatients exposed to cluster-A or cluster-B TB cases were defined as contacts of cluster-A or cluster-B, and others, as nonclustered contacts.
  
  
  RESULTS
  Among 355 inpatients with TB exposure, 134 (38%) were QFT-positive for LTBI. Univariate analysis showed that significant predictors for QFT-positivity were age, case-days of exposure to all TB cases (TB-all) and to sputum smear positive cases, number of source cases with cough, and exposure to cluster-A TB cases. Independent risk factors for LTBI were higher age [adjusted odds ratio (OR) 1.03, 95% confidence intervals (CI: 1.01-1.05)], TB-all exposure case-days ≥ 200 [adjusted OR 2.04 (1.06-3.92)] and exposure to cluster-A TB cases [adjusted OR 2.82 (1.30-6.12)] after adjustment for the sputum smear positivity, and cough variables of the source cases. The contacts of cluster-A had a greater risk of LTBI than did those of cluster-B, especially in the younger population (≤50 years) after adjustment [adjusted OR 2.64 (1.03-6.76)].
  
  
  CONCLUSIONS
  After TB outbreaks, more than one third of inpatients were QFT-positive for LTBI. Our findings suggest that, beside the infectiousness of source cases, intensity of exposure, and age of contacts, exposure to TB cases in potential genotyping clusters may be predictive for LTBI in this male psychiatric population.
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Internal Medicine, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Physiology, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Sheng-Wei
authors.initials: SW
authors.lastname: Pan
authors.affiliation: Institute of Physiology, National Yang-Ming University, Taipei, Taiwan; Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yu Ru
authors.initials: YR
authors.lastname: Kou
authors.affiliation: Department of Psychiatry, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan.
authors.forename: Tsung-Ming
authors.initials: TM
authors.lastname: Hu
authors.affiliation: Department of Internal Medicine, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan.
authors.forename: Yen-Chih
authors.initials: YC
authors.lastname: Wu
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yu-Chin
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Jia-Yih
authors.initials: JY
authors.lastname: Feng
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan. Electronic address: wjsu@vghtpe.gov.tw.
authors.forename: Wei-Juin
authors.initials: WJ
authors.lastname: Su
mesh_terms: D000328:Adult; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D006801:Humans; D007297:Inpatients / Q000523:psychology / Q000706:statistics & numerical data; D055985:Latent Tuberculosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011567:Psychiatric Department, Hospital / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013183:Sputum; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission
keywords: contact investigation; genotype; latent TB infection; prevalence; risk factor