Trends in drug-resistant tuberculosis after the implementation of the DOTS strategy in Shenzhen, China, 2000-2013.

ABSTRACT

SETTING: The DOTS strategy has been regarded as the most cost-effective way to stop the spread of tuberculosis (TB) since its launch by the World Health Organization. OBJECTIVE: To estimate the effects of DOTS by tracking long-term trends in multidrug-resistant TB (MDR-TB). DESIGN: A retrospective cohort study was conducted from 2000 to 2013 to analyse trends in resistance to anti-tuberculosis drugs and the effect of DOTS-based treatment in Shenzhen, China, using the χ2 test. RESULTS: An overall MDR-TB rate of 4.2% was observed between 2000 and 2013, with an annual reduction of 0.16%. From 2000 to 2013, trends in resistance to isoniazid (INH), rifampicin (RMP) and MDR-TB declined significantly in new TB patients (P < 0.01), but not in retreatment cases. Sputum smear conversion rates after 2 months of treatment decreased significantly, in particular after 2007, in new and retreatment cases. CONCLUSION: INH and RMP resistance and MDR-TB rates declined significantly, suggesting that DOTS-based programmes were successful in reducing drug resistance in new cases but not in retreatment cases. The decreasing sputum smear conversion rates may have been due to an increase in the number of migrants. These two findings suggest that TB is unlikely to be completely eliminated by 2050 in Shenzhen.