Multidrug-resistant tuberculosis in South Korea: a retrospective analysis of national registry data in 2011-2015

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) poses a threat to public health as a result of high treatment costs and unsatisfactory outcomes. OBJECTIVE: To elucidate trend, demographic and clinical characteristics and treatment outcomes of patients with MDR-TB between 2011 and 2015 in South Korea. METHOD: Data of patients with MDR-TB diagnosed between 1 January 2011 and 31 December 2015 were retrieved from the nationwide Internet-based TB notification system and analysed retrospectively. RESULTS: During the study period, 5192 MDR-TB patients were notified. We identified an increasing number of MDR-TB patients among foreign populations (from 1.3% to 7.7%), decreasing resistance rates to other anti-TB drugs (e.g., resistance to pyrazinamide, from 40.9% to 28.2%), a decreasing interval from treatment initiation to negative conversion of sputum culture (from 165.7 to 103.7 days) and shortening of treatment duration (719.7 to 613.2 days). However, treatment success rates did not change, and had an average of 65.7%. CONCLUSION: Despite decreasing resistance rates to other drugs and faster treatment responses, treatment outcomes did not improve during the study period. Strict management of MDR-TB patients on treatment should be adopted to improve treatment outcomes.