Extended treatment duration and recurrence in successfully treated drug-susceptible pulmonary tuberculosis with cavity on chest radiograph

Abstract

Cavity on chest radiograph is recognized as an independent risk factor for recurrence in pulmonary tuberculosis (TB), but evidence supporting extended treatment in these patients remains limited, particularly in real-world data from Korea.

Introduction

Pulmonary tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis and transmitted via inhalation of airborne droplet nuclei generated by patients with infectious pulmonary TB. It is a preventable and treatable disease, with treatment success rates approach 95% in drug-susceptible (DS) TB when managed with the standard 6-month regimen. However, advanced TB can lead to significant lung destruction and the development of cavitary lesions. The prevalence of cavitary TB has been reported to range from 29% to 87%.

Methods

Data collection

For the selected patients, baseline demographic data such as age, sex, and comorbidities were recorded at the time of diagnosis. Comorbidities were defined based on documented diagnoses, relevant medication use, or available clinical information in the medical records. Diabetes mellitus and hypertension were defined by documented diagnoses or use of glucose-lowering or antihypertensive medications

Statistical analysis

Continuous variables are presented as means ± standard deviations, and categorical variables are presented as counts (%). When comparing the two groups, t-tests were used to compare the means of continuous variables, while Pearson’s chi-square test or Fisher’s exact test were used to analyze the associations between categorical variables.

Results

Of the 1,204 patients in the cohort, 135 with multidrug-resistant or rifampin-resistant TB, 49 with isoniazid mono-resistant TB, and 13 with other mono-resistant TB were excluded. Additional exclusions included patients who did not receive the HRZE regimen (n = 36), experienced treatment failure (n = 4), died (n = 53), transferred to other clinics (n = 41), were lost to follow-up (n = 8), or discontinued treatment because of consent withdrawal or changes in diagnosis (n = 11). Consequently, 854 pan-susceptible DS TB patients who achieved treatment success with the standard HRZE regimen were identified

Conclusion

In this cohort of DS pulmonary TB patients with cavity on chest radiograph who successfully completed treatment, the small number of recurrence events limited our ability to definitively determine whether extending therapy beyond 200 days reduces bacteriologically confirmed recurrence. Although the adjusted estimate favored extended treatment, it was imprecise and should be interpreted as exploratory. 

Citation: Yoon C-S, Kim T-O, Shin H-J, Kim JS, Kim HW, Lee EG, et al. (2026) Extended treatment duration and recurrence in successfully treated drug-susceptible pulmonary tuberculosis with cavity on chest radiograph. PLoS One 21(9): e0357772. https://doi.org/10.1371/journal.pone.0357772

Editor: Jung Yeon Heo, Ajou University School of Medicine, KOREA, REPUBLIC OF

Received: February 11, 2026; Accepted: August 22, 2026; Published: September 10, 2026

Copyright: © 2026 Yoon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The ownership of the primary datasets lies with the Korea Disease Control and Prevention Agency (KDCA) and the Korea National Institute of Health (KNIH). The de-identified datasets generated and/or analysed during the current study can be made available for replication purposes upon reasonable request. Interested researchers should first contact the corresponding author, who will provide detailed instructions for submitting a request to the KDCA/KNIH (https://www.kdca.go.kr/kdca/index.do), including required documents such as a brief study proposal, institutional review board (IRB) approval, and a data use agreement. Access will be granted only with permission from the KDCA/KNIH and will be limited to the scope of the approved research.

Funding: This work was supported by the Research Program funded by a grant (BCRI24033) from Chonnam National University Hospital Biomedical Research Institute. The funders had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.