title: Effect of Diagnostic and Treatment Delay on the Risk of Tuberculosis Transmission in Shenzhen, China: An Observational Cohort Study, 1993-2010.
abstract: To understand better the risk of tuberculosis transmission with increasing delay in tuberculosis treatment, we undertook a retrospective cohort study in Shenzhen, China.
  
  
  
  All pulmonary tuberculosis cases in the Shenzhen tuberculosis surveillance database from 1993-2010 were included. Sputum smear positivity and presence of pulmonary cavity were used as proxies for risk of tuberculosis transmission.
  
  
  
  Among 48,441pulmonary tuberculosis cases, 70% presented with symptoms of pulmonary TB, 62% were sputum smear positive, and 21% had a pulmonary cavity on chest x-ray. 95.3% of patients self-presented for evaluation of illness after a median 58 days of delay after symptoms began. The proportion presenting sputum smear positive (p<0.001) and with a pulmonary cavity (p<0.001) increased significantly with increasing duration of delay.
  
  
  
  Delayed diagnosis and treatment of tuberculosis is associated with a significantly increased risk of pulmonary sputum smear positivity and pulmonary cavity. To decrease risk of transmission, treatment delay needs to be reduced further.
authors.affiliation: National Centre for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Shiming
authors.initials: S
authors.lastname: Cheng
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Yingzhou
authors.initials: Y
authors.lastname: Yang
authors.forename: Ping
authors.initials: P
authors.lastname: Chu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.forename: Meigui
authors.initials: M
authors.lastname: Zhao
authors.forename: Weiguo
authors.initials: W
authors.lastname: Tan
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Qingfang
authors.initials: Q
authors.lastname: Wu
authors.forename: Hongyun
authors.initials: H
authors.lastname: Guan
authors.forename: Jinhong
authors.initials: J
authors.lastname: Liu
authors.forename: Haitao
authors.initials: H
authors.lastname: Liu
authors.forename: Ray Y
authors.initials: RY
authors.lastname: Chen
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Jia
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D002681:China; D057210:Delayed Diagnosis; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity*; D012189:Retrospective Studies; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology*; D061665:Time-to-Treatment; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology / Q000635:transmission*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents