Directly Observed Therapy Short Course-Plus Versus DOTS for Retreatment of Relapsed Pulmonary Tuberculosis in Guangzhou

This is a prospective, randomized, parallel, controlled study comparing the efficacy and outcomes in the retreatment of pulmonary Tuberculosis (TB) in Guangzhou in a group using pretreatment susceptibility tests in selection of chemotherapy regimens and that in another group without using pretreatment susceptibility test results. The investigators hypothesize that selecting drug treatment on the basis of known susceptibility tests would lead to improved outcome compared with empiric treatment.

The aims are:1) To evaluate the efficacy and outcomes in the retreatment of pulmonary TB in Guangzhou by the use of pretreatment susceptibility tests in selection of chemotherapy regimens \& 2) To study the predictive factors of unfavourable outcomes in the retreatment of pulmonary TB in Guangzhou, where unfavourable outcomes include treatment failures and relapses.

The patients will be randomized into either a) The DOTS strategy consisting of the following measures: political commitment, case detection through bacteriologic evaluation, standardized treatment with supervision and patient support, an effective drug supply system, and a reporting and recording system that allows assessment of treatment; or b) The DOTS-Plus strategy includes additional measures including continuous drug resistance surveillance, culture, drug susceptibility testing for TB patients, and tailoring of individual drug regimen through the use of first and second-line drugs.

The Primary end point is the 18-month combined treatment failure/ relapse (unfavourable outcome) among rifampicin resistant group. Secondary endpoints include the 30-month combined treatment failure/ relapse (unfavourable outcome) among rifampicin resistant group, multidrug resistant tuberculosis (MDR-TB) cases and all retreatment cases; Sputum smear/conversion rate at 2m, 3m, 8m, 12m, 18m, and 24m; Drug resistance rates to various drugs in particular rifampicin, and rate of MDR-TB. The predictive factors of unfavourable treatment outcomes (including failure and relapse) will be analysed.

The management of retreatment cases by DOTS alone is often problematic, especially when there is resistance to rifampicin, and treatment failure / relapse with further resistances might result. With implementation of the "DOTS-plus" strategy, Hong Kong (HK) has achieved a low MDR-TB prevalence of around 1%. This study will provide important data on the predictors of treatment failure/ relapse of retreatment cases and whether the DOTS-plus strategy can effectively reduce the failure/relapse rate and the prevalence rate of MDR-TB in Guangzhou. The project will provide useful data on the surveillance, epidemiology and public health control of TB with a regional (cross-border) significance.