Purpose: We analyzed the trends and predictors of multidrug-resistant (MDR) or rifampicin-resistant (RR) tuberculosis (TB) in culture-positive cases in Shenzhen during 2012– 2020, after the implementation of improved strategies (scale-up molecular drug susceptibility testing [mDST], expansion of DST eligibility, and generous reimbursement of MDR-TB outpatient care costs).
Materials and Methods: We retrospectively extracted and analyzed data from the TB Information System on drug-resistant pulmonary tuberculosis diagnosed in Shenzhen during the 2012– 2020 period. We analyzed trends in RR- and MDR-TB rates in new cases during 2012– 2018 and 2018– 2020 periods, and among previously-treated cases during 2012– 2017 and 2017– 2020 periods, using Cochran-Armitage tests. We generated multivariate logistic regression models to analyze demographic predictors of MDR/RR-TB rates.
Results: We found 21,367 positive mycobacterial cultures in Shenzhen during the 2012– 2020 period, and 19,951 (93.4%) were identified as Mycobacterium tuberculosis  and had DST results (92.0% of those were mDST-based). Of these patients with DST results, 1630 (8.2%) were RR-TB, and 1142 (5.7%) were MDR-TB. Of the RR-TB, 70% were MDR-TB. The MDR/RR-TB rate in new TB cases increased significantly during the 2012– 2018 period (P _trend < 0.05), but it decreased in the 2018– 2020 period (P _trend > 0.05, with a significant trend for MDR-TB). Among previously treated cases, the temporal MDR/RR-TB rate trends did not differ significantly (P _trend > 0.05). Our multivariate analysis showed that age younger than 30 years, housework service/unemployment, local residency, and previous TB treatment were all predictors of MDR/RR-TB. The percentage of patients with MDR-TB on treatment increased from 49.4% in 2012 to 70.5% in 2020. The treatment success rate of patients with MDR-TB during the 2012– 2018 period was 71%.
Conclusion: During the study period in Shenzhen, the cases of MDR/RR-TB were detected, and the treatment enrollment increased and the MDR-TB rates decreased gradually after 2017. Decreasing trends may reflect the efficacy of improved strategies; however, their long-term impact on the MDR-TB burden remains to be investigated. The predictors of MDR-TB identified in our study should be considered when developing targeted MDR-TB control strategies.
Keywords: MDR/RR-TB, trend, predictors, Shenzhen, 2012– 2020