Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Mar 22;12(4):ofaf176.
doi: 10.1093/ofid/ofaf176. eCollection 2025 Apr.

Unrecognized Tuberculosis: Risk Factors for Smear-Positive/Cavitary Asymptomatic Cases

Jee Youn Oh  1 , Timothy C Rodwell  2 , Rehan R Syed  3 , Yousang Ko  4 , Jinsoo Min  5 , Hyung Woo Kim  6 , Hyeon-Kyoung Koo  7 , Yun-Jeong Jeong  8 , Eun Hye Lee  9 , Bumhee Yang  10 , Ganghee Chae  11 , Ju Sang Kim  6 , Sung-Soon Lee  7 , Hun-Gyu Hwang  12 , Jaehee Lee  13 , Heung Bum Lee  14 , Juock Na  15 , Jae Seuk Park  16
Affiliations

Unrecognized Tuberculosis: Risk Factors for Smear-Positive/Cavitary Asymptomatic Cases

Jee Youn Oh et al. Open Forum Infect Dis. .

Abstract

Background: Screening patients with asymptomatic active tuberculosis (TB) is crucial as they can transmit the disease. Identifying the risk factors for transmission is essential for targeted screening. Understanding how the infectiousness of asymptomatic patients with TB affects disease outcomes is crucial for developing strategies to control TB spread.

Methods: We analyzed the national Korean TB cohort data to determine the factors associated with transmission risk and clinical outcomes in patients with asymptomatic pulmonary TB. The primary outcome was the factors associated with a risk factor for transmission, while the secondary outcome was mortality in asymptomatic patients with pulmonary TB stratified by transmission risk.

Results: Among 20 455 patients with pulmonary TB, 7434 (36.4%) were asymptomatic, while 1520 (25.5%) had potential transmission risks, indicated by a positive sputum acid-fast bacillus smear test or cavitation on chest radiographs. The factors associated with a higher transmission risk included male sex (odds ratio [OR], 1.385; 95% CI, 1.172-1.636; P < .001), low body mass index (BMI; OR, 1.687; 95% CI, 1.420-2.004; P < .001), current smoking (OR, 1.443; 95% CI, 1.213-1.716; P < .001), diabetes (OR, 1.399; 95% CI, 1.201-1.629; P < .001), and autoimmune disease (OR, 2.233; 95% CI, 1.295-3.850; P = .004). The mortality rate was higher in patients with a risk factor for transmission risk than in those without (9.3 vs 7.1%; P = .008).

Conclusions: Lean, smoking men with asymptomatic TB who have DM and/or autoimmune diseases have higher transmission and mortality risk. Asymptomatic populations with these risk factors warrant targeted screening.

Keywords: asymptomatic; cohort studies; pulmonary; transmission; tuberculosis.

PubMed Disclaimer

Conflict of interest statement

Potential conflicts of interest. T.C.R. receives funding support from FIND through a service contract with UC San Diego. T.C.R. receives grant funding from the National Institutes of Health and US Dept of Defense to develop and evaluate TB diagnostics. T.C.R. is a co-founder, board member, and unpaid shareholder of Verus Diagnostics Inc. Verus Diagnostics had no role in the design or implementation of the study. T.C.R. is a co-inventor on patents pertaining to drug-resistant TB. The terms of this arrangement were reviewed and approved by the University of California, San Diego, in accordance with its conflict of interest policies. All authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1.
Figure 1.
Flowchart. aInitial sputum study: sputum smear, polymerase chain reaction, culture all done. Flowchart depicting the inclusion process of patients with asymptomatic tuberculosis who were smear-positive or cavitary in the study. Abbreviations: AFB, acid-fast bacilli; TB, tuberculosis.
See this image and copyright information in PMC

References

    1. Cheng J, Wang L, Zhang H, Xia Y. Diagnostic value of symptom screening for pulmonary tuberculosis in China. PLoS One 2015; 10:e0127725. - PMC - PubMed
    1. Cavaco MJ, et al. Determinants of tuberculosis diagnosis delay. Eur Respir J 2023; 62:PA1057.
    1. Zhang L, et al. Analysis of care-seeking and diagnosis delay among pulmonary tuberculosis patients in Beijing, China. Front Public Health 2024; 12:1369541. - PMC - PubMed
    1. Menzies D. Screening for latent tuberculosis infection. JAMA Netw Open 2023; 6:e2312114. - PubMed
    1. Tan Q, Huang CC, Becerra MC, et al. Chest radiograph screening for detecting subclinical tuberculosis in asymptomatic household contacts, Peru. Emerg Infect Dis 2024; 30:1115–24. - PMC - PubMed