Treatment Outcome of Multidrug-resistant Tuberculosis in Japan - the First Cross-sectional Study of Japan Tuberculosis Surveillance Data

Background: Multidrug resistant-tuberculosis (MDR-TB) is a major global health concern. Its treatment requires toxic medications, is longer and costlier than drug-susceptible TB, and often results in productivity losses and poor outcomes. In Japan, a TB middle-burden country, reports on treatment outcome of MDR-TB patients have only been institution-based. We thus sought to shed some light on the nationwide treatment status and outcome of MDR-TB patients in Japan.

Methods: Characteristics and treatment status and outcome of MDR-TB patients notified between 2011 and 2013 were evaluated using the data from the Japan TB Surveillance (JTBS) system. Since the treatment outcome from the surveillance data was not directly linked to any clinical records or drug susceptible test results, we also analyzed the treatment duration of MDR-TB cases in an attempt to validate our results.

Results: Between 2011 and 2013, a total of 172 MDR-TB patients had been notified to the JTBS as MDR-TB. 68.6% (118/172) were males and 70.9% (122/172) were Japan-born - however, over the study period, the proportions of foreign-born, of those in the age group 15-64 years old and of new cases have increased. The overall treatment completion rate was 57.0%, however, when restricted to patients aged 64 years old and below, the rate improved to 71.6%. Treatment duration of 29.2% of those patients who had been recorded as "treatment completed" in fact fell short of the 540 days, the minimum duration as recommended by the Japanese guideline.

Conclusions: Increasing proportion of new cases, and of younger age groups among the MDR-TB patients indicate new transmissions. Better strategies for early detection and containment of MDR-TB are urgently needed. The overall treatment completion rate was 57.0% over the three-year study period. However, when restricting the result to those aged 64 years old and below, the rate improved to 71.6%, which was comparable to similarly industrialized countries. Due to the limitations of the JTBS data, a comprehensive survey of all MDR-TB patients may be necessary to provide more concrete evidence for decision-making.