Effect of Diagnostic and Treatment Delay on the Risk of Tuberculosis Transmission in Shenzhen, China: An Observational Cohort Study, 1993-2010. e67516

• Published in: PloS one Vol. 8; no. 6
• Main Authors: Cheng, Shiming, Chen, Wei, Yang, Yingzhou, Chu, Ping, Liu, Xiaoli, Zhao, Meigui, Tan, Weiguo, Xu, Li, Wu, Qingfang, Guan, Hongyun
• Format: Journal Article
• Language: English
• Published: 01.06.2013
• Subjects: Cavities; Mycobacterium; China, People's Rep
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0067516

Introduction To understand better the risk of tuberculosis transmission with increasing delay in tuberculosis treatment, we undertook a retrospective cohort study in Shenzhen, China. Methods 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. Results 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. Conclusions 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.