RELAPSE OF TUBERCULOSIS AMONG PATIENTS COMPLETING TREATMENT IN VIETNAM: A NESTED CASE-CONTROL STUDY

Background: In Japan, recommended treatment durations are 6 or 9 months for patients with isoniazidand rifampin-susceptible tuberculosis (TB) and, following culture conversion, 18 months for patients with multidrug resistant TB (MDR-TB). However, Japan does not report nationwide data of treatment duration of MDR-TB. Aims: To examine treatment duration of MDR-TB patients registered in TB surveillance in Japan between 2011 and 2012. Methods: We analysed routinely collected data of newly notified MDR-TB patients from national TB surveillance system in Japan, in terms of treatment duration and co-morbidities. Treatment duration was calculated by subtracting the therapy start date from the therapy end date. Results: Between 2011 and 2012, a total of 147 MDR-TB patients were newly notified to TB surveillance. 85 (57.8%) had completed treatment at the end of 2015. Duration of treatment was calculated for 80 (94.1%) patients. Mean of treatment duration was 724 days. Median was 761 days and interquartile range was 563-859 days. Mean of treatment duration by age group 0-29, 30-39, 40-49, 50-59, 60-69, 70+ was 663 days, 803 days, 813 days, 831 days, 747 days and 601 days, respectively. Mean of treatment duration by male and female was 737 days and 701 days. Mean of treatment duration by diabetes and nondiabetes was 837 days and 709 days. There were no HIV-positive patients. Conclusions: On average, the treatment duration of MDR-TB patients in Japan exceeded 24 months, and of those with DM was 28 months. The treatment duration was the longest among those aged 50-59. Further clinical study may be necessary to investigate the possible risk factors for prolonged treatment.