Sputum acid-fast bacilli smear positivity and cavitary pulmonary disease across COVID-19 pandemic phases in Taiwan

Changes in tuberculosis (TB) characteristics across COVID-19 response periods remain unclear. To examine changes in sputum acid-fast bacilli (AFB) smear positivity and cavitary pulmonary disease among patients with pulmonary TB in Taiwan. This retrospective cross-sectional study included consecutive adults newly diagnosed with pulmonary TB at a medical center in southern Taiwan from 2017 to 2024. Patients were categorized into pre-pandemic (2017–2019), pandemic (2020–2022), and COVID-19 transition (2023–2024) periods. Multivariable logistic regression was used to identify factors associated with smear positivity and cavitary disease. Among 789 patients, 341 were diagnosed in the pre-pandemic period, 270 during the pandemic, and 178 during the COVID-19 transition. Sputum smear results were available for 738 patients (93.5%). Smear positivity was 34.4%, 32.0%, and 48.6%, respectively ( p = 0.001). The COVID-19 transition period was independently associated with smear positivity (adjusted odds ratio [aOR], 1.92; 95% confidence interval [CI], 1.28–2.87; p = 0.002). Cavitary disease prevalence was 10.3%, 12.6%, and 14.0%, respectively ( p = 0.412), and neither period was independently associated with cavitation. Diabetes mellitus and recurrent TB were independently associated with cavitary disease. Sputum AFB smear positivity was higher during the COVID-19 transition period than before the pandemic, without a corresponding difference in cavitary disease. These findings indicate that temporal differences in sputum AFB smear positivity were not accompanied by a corresponding increase in radiographically documented cavitary disease.