Efficacy of Extended Treatment in Drug-Susceptible Pulmonary Tuberculosis with Cavitary Lesions or Positive Culture at 2 Months

Extended treatment is recommended for patients with pulmonary tuberculosis (TB) and cavitary lesions or positive culture at 2 months, but evidence remains limited. A retrospective analysis across 18 Korean institutions compared recurrence between standard (≤ 200 days) and extended treatment (> 200 days) in patients with drug-susceptible TB and cavitary lesions on chest radiography or positive sputum cultures at 2 months. Among 173 patients, 65 (37.6%) received standard and 108 (62.4%) extended treatment. Recurrence rates were similar (3.1% vs. 1.9%, p = 0.60), even after propensity score matching (4.7% vs. 2.3%, p = 0.56). Logistic regression analysis of all 854 patients with drug-susceptible TB with treatment success revealed chronic lung disease (OR 6.49, CI: 2.21–19.10, p < 0.01) and medication interruption exceeding 7 days (OR 4.43, CI: 1.63–12.03, p < 0.01) as significant predictors of recurrence. Positive culture at 2 months (OR 0.85, CI: 0.11–6.87, p = 0.88), cavitary lesions (OR 0.94, CI: 0.31–2.83, p = 0.91), either factors (OR 0.98, CI: 0.39–2.47, p = 0.99), and extended treatment (OR 1.17, CI: 0.49–2.81, p = 0.72) were not significant. Extended treatment did not reduce recurrence in patients with drug-susceptible TB and cavitary lesion or positive culture at 2 months.